Why should someone replace ALL the capacitors on old Tube equipment?

[olds...@tubes.com]

Why should someone replace ALL the capacitors on old Tube equipment?

It seems that some people advocate that.

I understand that the electrolytic caps contain chemicals which decay
over time, from the chemicals corroding the metal parts. So,
electrolytic caps should always be replaced. But why replace the old
paper caps coated with wax? All they are, is metal foil and paper rolled
up, and as long as the wax is sealing them to keep out moisture, why
should they become defective?

And for that matter, what are the new ones made from? Aside from being
sealed inside of some sort of plastic (instead of wax), are they not the
exact same thing inside?

While this is not part of my original intent for this message, I want to
ask if anyone remembers the old oil filled electrolytic caps in the
1930's and 40's radios? I never understood what the oil did inside of
them. But what I do remember is having one of them "blow". *SCARY SHIT*.
I plugged in some ancient chassis with those old oil filled caps, and
all of a sudden there was hot oil spraying all over me, from the tiny
hole in the top of it. After that, I always put a tin can over those
caps before plugging the device in. (or just replaced them). Those
seemed to almost always be bad. (Probably why they were not used to too
many years).

[ohg...@gmail.com]

If you remove every paper and foil capacitor from an old tube anything and check them on a quality checker, you'll find most if not all showing some sort of defect. They may read OK value wise, but run a few hundred volts through them and you'll find most have a lot of internal leakage. The fact is that moisture does eventually penetrate the capacitors and causes problems.

I've heard that old Radiolas use large banks of paper and foil capacitors instead of electrolytics and most do just fine with their original caps. Supposedly it's because of the particularly fine rice paper imported from Japan used to construct these capacitors during the 1920s. These rice paper caps might escape degradation over the decades. Perhaps those who've restored a bunch of these can comment if they actually did dynamic testing of the capacitors.

[Foxs Mercantile]

On 2/2/2017 2:53 PM, olds...@tubes.com wrote:
> Why should someone replace ALL the capacitors on old Tube equipment?
>
> It seems that some people advocate that.

Most "old" radios are from 1930-1960.
That makes them 87-57 years old.

Manufacturing has changed a lot.

I change all the caps simply because I don't waste my time
"troubleshooting" bad caps.
Bad caps can cause collateral damage.
Why risk it for the cost (low) of replacement parts?

Old electrolytic filter caps dry out.
It's a fools game to waste time trying to reform them.
Paper dielectric capacitor absorb moisture and that
combines with the acids in the paper and cause them to fail.

For the most part, mica, silver dipped mica and ceramic
capacitors are very reliable. The band ones, you can find
AFTER you've replaced the usual suspects and can actually
trouble shoot the radio rather than running around in circles
chasing known bad parts.

Yes, I've had to replace the occasional vacuum tube, or found
an open coil, but for the most part 99% of the radios I've
worked on, worked to a fashion by just replacing known bad
parts. I.e. Paper and electrolytic capacitors.



--
Jeff-1.0
wa6fwi
http://www.foxsmercantile.com

[olds...@tubes.com]

On Thu, 2 Feb 2017 15:38:45 -0600, Foxs Mercantile <jda...@att.net>
wrote:

I'm 66 years old. According to my doctor, I dont have any bad
capacitors, (just arthritis). :)

Seriously, I wonder what the life expectancy is for the new caps
(meaning the replacements for the wax coated paper caps. ???)

And what are these newer ones made from?

I know the mica and ceramic caps are reliable and last almost forever.

A for electrolytic caps, it seems that the newer ones have a much
shorter life than the old ones did. You'd think that it would be the
other way around with modern technology, but today the name of the game
to to make stuff as cheaply as possible, for profit, not long life.
After all, today's electronics, cars, even homes are disposible. That's
why those old radios still work after 60 or 80 years, while most stuff
made today is in a landfill in less than 10 years.

One other thing that most people dont know, is that if we have a nuclear
blast, all of the semiconductors will cease to work. That means all
modern electronics, radios, tvs, cpmputers, cars, and darn near
everything around us, will stop working. The only stuff that will still
work are tube based electronics and vehicles made which still have
ignition points in their distributors.

Most likely WE wont survive either, but if we do, all we will have is
the old stuff from the 1960s and earlier, to rely on. The internet will
be gone, since it's all run with silicon. Most radio transmissions will
also be gone, except those still powered with tubes. This day is coming
soon, and we will be tossed back into the early 1900s. Thats why we need
to keep this old technology alive. The gear we relied on during WW2 is
the gear we will rely on once again during the upcoming WW3.

[Jim Mueller]

Actually, the electrolytic capacitors are more likely to be good than the
paper capacitors. Almost all of the paper capacitors I have from the
"old days" are bad, even if they were never used while a small number of
the electrolytics are still functional.

The paper capacitors were made of sheets of foil separated by paper,
"sealed" in wax. Unfortunately, wax isn't a very good seal; moisture can
penetrate it. These capacitors were a know failure point 10 years after
a set was made. There just wasn't anything better to replace them with
(at a reasonable price). Modern capacitors are made from plastic film
that is much less affected by moisture and is a better insulator in the
first place.

The old electrolytic capacitors you are talking about don't sound like
the oil filled variety. Indeed, if they are electrolytic, they aren't
oil filled. Oil filled capacitors aren't polarized and many of them are
good today. They were the high quality capacitors used in military and
premium industrial equipment; you seldom find them in consumer gear
unless someone has repaired it with surplus parts. The capacitors you
talk about are more likely wet electrolytics. They aren't filled with
oil but with an acid. They are indeed all bad; don't power a set that
has them. Sometimes they leak if you turn them upside down (the vent
hole you mentioned). And be careful not to puncture them while you are
removing them. If there is still any acid inside, it will corrode any
metal it gets on.

You can still get high quality electrolytic capacitors from authorized
distributors like Mouser or Digi-Key. No-name ones from Amazon or Ebay
are likely to be junk. Name brand ones from these latter sources may be
counterfeit.

While tube electronics may survive a nuclear war, it is irrelevant.
There won't be any electricity to run them. The power plants are
controlled by computers. Likewise, having your own generator won't help
either. Many of the new ones are also semiconductor based, and you won't
be able to get gas to run them since the pumps at the gas station are run
by electricity which won't be available. Solar cells are also
semiconductors and the inverters used with them also use semiconductors.
So, if there is a WW3, don't count on ANYTHING electrical working.

--
Jim Mueller wron...@nospam.com

To get my real email address, replace wrongname with dadoheadman.
Then replace nospam with fastmail. Lastly, replace com with us.

[Jeff Liebermann]

On Thu, 02 Feb 2017 16:44:53 -0600, olds...@tubes.com wrote:

>I'm 66 years old. According to my doctor, I dont have any bad
>capacitors, (just arthritis). :)

I'm 69 years old. My body mechanic says I have pump and inside
plumbing problems. Perhaps I should replace him with a plumber?

>Seriously, I wonder what the life expectancy is for the new caps
>(meaning the replacements for the wax coated paper caps. ???)

There are online lifetime calculators for electrolytic and other types
of capacitors. For example:
<http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx>
<http://www.chemi-con.com/education> (click on Capacitor Life)
The major culprit is internal heating from high ripple current
resulting the electrolyte leaking or evaporating. Temperature also
has a big effect. There are graphs on the capacitor data sheets that
approximate the lifetime characteristics.

>And what are these newer ones made from?

For electrolytics, try polymer caps:
<https://en.wikipedia.org/wiki/Polymer_capacitor#Lifetime.2C_service_life>
<http://www.mouser.com/pdfdocs/Panasonic_Capacitors_WP_final.PDF>

>I know the mica and ceramic caps are reliable and last almost forever.

Not all ceramics are that reliable. MLCC (multi-layer ceramic caps)
are rather fragile and microphonic.

>A for electrolytic caps, it seems that the newer ones have a much
>shorter life than the old ones did.

Nope. The old ones filtered at 120 Hz. The new caps filter at 100 to
300 KHz. Internal dissipation follows frequency.

>That's
>why those old radios still work after 60 or 80 years, while most stuff
>made today is in a landfill in less than 10 years.

Todays products are intentionally designed to be difficult to repair
and to only last as long as the warranty period. With the proper
design tools and models, it is possible to predict the life of an
electronic (or mechanical) product. Anything that lasts longer than
the warranty period is deemed to be "over-designed". It is then
redesigned using lower rating or cost components so that everything
blows up at the same time. I've seen it happen.

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Adrian Tuddenham]

<olds...@tubes.com> wrote:

> Why should someone replace ALL the capacitors on old Tube equipment?
>
> It seems that some people advocate that.

One of the factors that is often overlooked is the tolerance of the
circuit to the various types of wear-out mechanism.

If a cathode by-pass capacitor on the sound output valve goes leaky, it
would have to leak very badly indeed (and measure only a few hundred
ohms) before it upset the operating conditions of the valve. On the
other hand, if an inter-stage coupling capacitor begin to leak and puts
even a small proportion of the anode voltage of the first valve across
the grid leak of the second, it will upset the second valve very badly
and may even destroy it.

Electrolytic smoothing capacitors in the HT line will leak even when
brand new, but the leakage is usually fairly small once they have
settled down. If they later begin to leak badly, this will cause
internal heating and damage which may not be obvious - the set will
appear to carry on working as normal. Eventually, when the leakage
increases even more, something in the power supply will fail due to
overloading or the capacitor itself bursts; but until that point, there
may be no hint that things are going wrong because the circuit is
reasonably tolerant of that sort of leakage.

I have repaired QuadII amplifiers which almost met specification even
though the internal voltages were all over the place, most of the
capacitors were leaking and some of the resistors had changed value too.
The initial design was intended to be tolerant of a wide range of
component values (close-tolerance components were very expensive) so it
wasn't badly upset by drift due to ageing.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[Phil Hobbs]

Oliver Wendell Holmes wrote a very funny poem about that, "The Deacon's
Masterpiece, Or, The Wonderful One-Hoss Shay".

Here it is, read by Eddie Albert.

https://www.youtube.com/watch?v=wiOHhhwnK6k

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

[pf...@aol.com]

On Thursday, February 2, 2017 at 4:33:51 PM UTC-5, ohg...@gmail.com wrote:

Perhaps those who've restored a bunch of these can comment if they actually did dynamic testing of the capacitors.

I have done a fair number of AK55s and their Radiola and other-brand contemporaries, using potted 1 & 2 uF paper caps. I will typically test them at 500VAC on a proper full-voltage cap tester.

I have never, repeat, never found a bad potted paper cap in an undamaged device. The secret, in my opinion, is that the caps are massive (I have unpotted a couple for the sake of curiosity from rusted-out hulks), with wide clearances. The potting tar makes for an excellent seal as well.

Peter Wieck
Melrose Park, PA

[Tom Biasi]

On 2/3/2017 10:12 AM, Phil Hobbs wrote:
> On 02/02/2017 09:36 PM, Jeff Liebermann wrote:
>> On Thu, 02 Feb 2017 16:44:53 -0600, olds...@tubes.com wrote:

...

>>
>
> Oliver Wendell Holmes wrote a very funny poem about that, "The Deacon's
> Masterpiece, Or, The Wonderful One-Hoss Shay".
>
> Here it is, read by Eddie Albert.
>
> https://www.youtube.com/watch?v=wiOHhhwnK6k
>
> Cheers
>
> Phil Hobbs
>

A wonderful poem and read very well.

[Jeff Liebermann]

Thanks, that was good and quite appropriate.

While attending college, I lived for a time in a large old house aptly
named "the fire trap". I could hear termites chewing away in the
walls. About 3 years after graduating, I returned to visit the
school, and drove by house. It looked much the same as when I lived
there. The next day, on my way out of town, I drove by again and
found that the house had collapsed in a heap. No wall was left
standing. According to the news, it had fallen down by itself and
without warning, injuring a few students in the process. It's much
like the medieval cathedrals, bridges, and other structures, where the
failure of one tiny arch, will cause the entire structure to collapse.


In a previous life, I tried to design a "warranty timer" into a
product. Actually, it was suppose to accumulate and display the
amount of time that the unit had been powered on to help establish
maintenance intervals. In previous products, a mechanical
counter-timer was used, but for this version, it was deemed too big
and expensive.
<http://www.alliedelec.com/images/products/Small/70132720.jpg>
I found a company that made an electrochemical equivalent. It was
housed in a glass cylinder, similar to a common 3AG glass fuse. Inside
was some chemical solution. When a few volts of DC was applied,
electrolytic action caused one end to slowly turn dark, thus
indicating the amount of time that the DC was applied. Sorry, but I
couldn't find the vendor or an equivalent online. When the required
maintenance was performed, the indicator would be replaced as it could
not be reset.

During the design phase, I liked to joke about installing a 2nd timer
in the product, which would blow it up after a specified operating
life. I even designed a place for it on one of PCB's. I stopped
joking after I found that management was taking me seriously and
discussing such things was how to handle extended warranties. The
device was later removed in a cost reduction exercise, but the
component outline remained in the printed manual, resulting in
numerous embarrassing questions because someone had labeled the part
as a "warranty timer".

[cl...@snyder.on.ca]

On Fri, 03 Feb 2017 09:32:07 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

Something like a coulometer???

[Nick Danger]

On 2/2/2017 9:13 PM, Jim Mueller wrote:

> While tube electronics may survive a nuclear war, it is irrelevant.
> There won't be any electricity to run them. The power plants are
> controlled by computers. Likewise, having your own generator won't help
> either. Many of the new ones are also semiconductor based, and you won't
> be able to get gas to run them since the pumps at the gas station are run
> by electricity which won't be available. Solar cells are also
> semiconductors and the inverters used with them also use semiconductors.
> So, if there is a WW3, don't count on ANYTHING electrical working.

Seeing as you brought up WW3, for those of you that may not know it, a
new president singlehandedly advanced the Doomsday Clock by 30 seconds
just last week. Heck of a job!

[ohg...@gmail.com]

You probably don't know this, but it's not a *real clock*. It's one of those cardboard affairs that we used to teach our children how to tell time. Some snowflakes have one that they labelled "Doomsday" on it in crayon and they move the hands one way or the other depending on how *they* feel about things.

If there were no Muslims and Communists, this would be a pretty peaceful world actually. And speaking of Communists, it was lovely of the outgoing U.S. president to throw the cold war back decades before he left.

That's a heck of a job!

[pf...@aol.com]

Lemme See:

Austria in 1936.
Chamberlain: Peace in our Time.

And we all know how that turned out.

Crimea in 2016.
Ukraine in 2017? It is a shooting war to this day, and Ukraine is losing.
tRump: Peace in our time, and let's go to bed.

Expect any different? Only this time with Nukes.

On some great and glorious day the plain folks of the land will reach their heart's desire at last, and the White House will be adorned by a downright moron.

In this world of sin and sorrow there is always something to be thankful for; as for me, I rejoice that I am not a Republican.

H. L. Mencken

[Jim Mueller]

On Fri, 03 Feb 2017 13:50:22 +0000, Adrian Tuddenham wrote:

> <olds...@tubes.com> wrote:
>
>> Why should someone replace ALL the capacitors on old Tube equipment?
>>
>> It seems that some people advocate that.
>
> One of the factors that is often overlooked is the tolerance of the
> circuit to the various types of wear-out mechanism.
>

>snip

True. But the reason to replace them ALL is that if you only replace the
one(s) causing a problem, another will fail later, then another still
later. It is much easier to do them all at once than to have to repair
the same unit over and over as they fail one after another. Been there,
done that.

[Benderthe.evilrobot]

<olds...@tubes.com> wrote in message
news:32779ctsu0qa604ak...@4ax.com...

> Why should someone replace ALL the capacitors on old Tube equipment?
>
> It seems that some people advocate that.
>
> I understand that the electrolytic caps contain chemicals which decay
> over time, from the chemicals corroding the metal parts. So,
> electrolytic caps should always be replaced. But why replace the old
> paper caps coated with wax? All they are, is metal foil and paper rolled
> up, and as long as the wax is sealing them to keep out moisture, why
> should they become defective?

Waxed paper capacitors are notorious for moisture absorbtion and becoming
leaky.

There are plenty of other types of dry capacitors that don't last forever in
the high temperature around tubes.

[Benderthe.evilrobot]

<olds...@tubes.com> wrote in message
news:nua79chv7ato1hdgi...@4ax.com...

I've seen loads of ceramic caps fail - but mostly in TV horizontal scan
sections where the frequency is over 15kHz and high voltage pulse
conditions.

This got worse with ever increasing PC monitor resolutions.

AFAICR; mica caps were pretty reliable - in most of the places I found them,
they were used for precision and a specific tempco.

[Tom Biasi]

Get off of it. You lost.

[Ralph Mowery]

In article <5894f007$0$55577$b1db1813$796...@news.astraweb.com>,
wron...@nospam.com says...

>
> On Fri, 03 Feb 2017 13:50:22 +0000, Adrian Tuddenham wrote:
>
> > <olds...@tubes.com> wrote:
> >
> >> Why should someone replace ALL the capacitors on old Tube equipment?
> >>
> >> It seems that some people advocate that.
> >
> > One of the factors that is often overlooked is the tolerance of the
> > circuit to the various types of wear-out mechanism.
> >
> >snip
>
> True. But the reason to replace them ALL is that if you only replace the
> one(s) causing a problem, another will fail later, then another still
> later. It is much easier to do them all at once than to have to repair
> the same unit over and over as they fail one after another. Been there,
> done that.

I believe in replacing most all the components that are similar when one
fails in older equipment. I worked at a large plant and when a 200 HP
motor speed control went bad a factory man was called in. He found two
power diodes bad. As this was a 3 phase motor and had one more, I asked
him to replace it. He told me they were about $ 100 each. I said go
ahead. The down time was costing us much more than that an hour,and to
get him back in would cost a lot more if the 3 rd one failed, it would
be just good insurance. The diode may or may not have been weakened in
some way. $ 100 is a small part of over $ 50,000 or more.

[Michael Black]

On Fri, 3 Feb 2017, Jim Mueller wrote:

> On Fri, 03 Feb 2017 13:50:22 +0000, Adrian Tuddenham wrote:
>
>> <olds...@tubes.com> wrote:
>>
>>> Why should someone replace ALL the capacitors on old Tube equipment?
>>>
>>> It seems that some people advocate that.
>>
>> One of the factors that is often overlooked is the tolerance of the
>> circuit to the various types of wear-out mechanism.
>>
>> snip
>
> True. But the reason to replace them ALL is that if you only replace the
> one(s) causing a problem, another will fail later, then another still
> later. It is much easier to do them all at once than to have to repair
> the same unit over and over as they fail one after another. Been there,
> done that.
>

And that brings in another issue. A lot of that old equipment is really
hard to disassemble. So the effort to take it apart is greater than
changing all the capacitors, so one might as well while the thing is
apart.

Low value capacitors don't cost much, so replacing them all won't kill
most people. Electrolytics can be more expensive, but in consumer type
tube equipment, there are only a few, in the power supply and bypassing
the cathode in the audio stages, maybe a few more.

It shifts with solid state equipment, a whole lot more electrolytics since
transistors are low voltage low current (ie low impedance) rather than
tube's high impedance. And then with switching supplies, electrolytics
see much harder service since they are expected to filter AC frequencies
above audio, while previously electrolytics only saw 120Hz or audio
frequencies.

That's another issue. The time tracking down one bad capacitor can be
costly, if you just replace all the capacitors that may be as fast or
faster than figuring out which one is bad (and then another capacitor of
the same vintage may go bad the next week).

Michael

[Benderthe.evilrobot]

"Jim Mueller" <wron...@nospam.com> wrote in message
news:5894f007$0$55577$b1db1813$796...@news.astraweb.com...

> On Fri, 03 Feb 2017 13:50:22 +0000, Adrian Tuddenham wrote:
>
>> <olds...@tubes.com> wrote:
>>
>>> Why should someone replace ALL the capacitors on old Tube equipment?
>>>
>>> It seems that some people advocate that.
>>
>> One of the factors that is often overlooked is the tolerance of the
>> circuit to the various types of wear-out mechanism.
>>
>>snip
>
> True. But the reason to replace them ALL is that if you only replace the
> one(s) causing a problem, another will fail later, then another still
> later. It is much easier to do them all at once than to have to repair
> the same unit over and over as they fail one after another. Been there,
> done that.

So have I.

[olds...@tubes.com]

On Fri, 3 Feb 2017 14:08:37 -0500, Nick Danger <ni...@third.eye.net>
wrote:

Yes, precisely why I feel WW3 is a lot closer and more likely than
before. This has nothing to do with my own political party preferences,
or anything else, just the "person" himself (president). However, lets
NOT get into a political discussion on here. Seems like everywhere on
the internet has turned to politics lately. But I still do not feel
safe, with the current state of the world and the current US president.
It seemed a lot safer before, even though the world in general seems a
lot worse than it was in the last few decades.

[Benderthe.evilrobot]

<olds...@tubes.com> wrote in message
news:1pv99cptj879dqmtm...@4ax.com...

Trump is using executive orders for everything, that's basically ruling by
decree - I don't know how that's any different to a dictatorship.

[olds...@tubes.com]

On Thu, 02 Feb 2017 18:36:08 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

>On Thu, 02 Feb 2017 16:44:53 -0600, olds...@tubes.com wrote:
>
>>I'm 66 years old. According to my doctor, I dont have any bad
>>capacitors, (just arthritis). :)
>
>I'm 69 years old. My body mechanic says I have pump and inside
>plumbing problems. Perhaps I should replace him with a plumber?
>

Definitely sounds like you need a plumber :)

>>Seriously, I wonder what the life expectancy is for the new caps
>>(meaning the replacements for the wax coated paper caps. ???)
>
>There are online lifetime calculators for electrolytic and other types
>of capacitors. For example:
><http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx>
><http://www.chemi-con.com/education> (click on Capacitor Life)
>The major culprit is internal heating from high ripple current
>resulting the electrolyte leaking or evaporating. Temperature also
>has a big effect. There are graphs on the capacitor data sheets that
>approximate the lifetime characteristics.

OK

>
>>And what are these newer ones made from?
>
>For electrolytics, try polymer caps:
><https://en.wikipedia.org/wiki/Polymer_capacitor#Lifetime.2C_service_life>
><http://www.mouser.com/pdfdocs/Panasonic_Capacitors_WP_final.PDF>
>

So, what are the BEST ones? For example, I am getting a Hallicrafters
sx-99 radio, to recap it, what should I use for the small caps (not
electrolytics)? Should I use the "orange drops", or is there something
better? I'd rather spend a few bucks more and get the best.

By the way, why are all the caps now rated at some oddball figure.
For example, instead of .05, it's ,047? or instead of .003 it's .0033.

Same for the 'lytics instead of 30mf, they are 33mf and so on.....

>>I know the mica and ceramic caps are reliable and last almost forever.
>
>Not all ceramics are that reliable. MLCC (multi-layer ceramic caps)
>are rather fragile and microphonic.

What do those look like? Are they the ones with colored dots that look
like dominos? (But I think those are mica caps, if I'm not mistaken).

I remember those squarish brown ones with the leads on the bottom, those
were supposed to be superior. (Silver mica, maybe?)

And the round ceramics were said to be good too.

>
>>A for electrolytic caps, it seems that the newer ones have a much
>>shorter life than the old ones did.
>
>Nope. The old ones filtered at 120 Hz. The new caps filter at 100 to
>300 KHz. Internal dissipation follows frequency.
>

Can you explain that. I dont understand...
(I would think that a 'lytic in a power supply would only need to filter
at 120hz, or would some filter at 60hz also, depending on the
configuration?

>>That's
>>why those old radios still work after 60 or 80 years, while most stuff
>>made today is in a landfill in less than 10 years.
>
>Todays products are intentionally designed to be difficult to repair
>and to only last as long as the warranty period. With the proper
>design tools and models, it is possible to predict the life of an
>electronic (or mechanical) product. Anything that lasts longer than
>the warranty period is deemed to be "over-designed". It is then
>redesigned using lower rating or cost components so that everything
>blows up at the same time. I've seen it happen.

I totally agree. You cant identify parts anymore and if you can, you
cant get them. Especially ICs.

In the 60s and 70s, I loved to work on electronics. Mostly tube stuff.
The early transistor stuff was not too bad, but as soon as they began
using ICs, I lost interest in working on it.

Now, 40+ years later, I am gtting back into it, but only working on
antique tube stuff, which is what i enjoy. Modern stuff is far too
complicated, far too small (hard to see with my aging eyes too), and
does nothing but frustrate me.

Sure, I have built every computer I have owned (or rebuilt from parts of
thrown away ones). But with computers you just change boards, not
individual components.

I guess going back to the tube stuff makes me feel young again!

[Tom Biasi]

It's a very complex issue. Your feelings are just that, yours.

[Look165]

They call it "preventive maintainance".

olds...@tubes.com a écrit :

> Why should someone replace ALL the capacitors on old Tube equipment?
>
> It seems that some people advocate that.
>

> I understand that the electrolytic caps contain chemicals which decay
> over time, from the chemicals corroding the metal parts. So,
> electrolytic caps should always be replaced. But why replace the old
> paper caps coated with wax? All they are, is metal foil and paper rolled
> up, and as long as the wax is sealing them to keep out moisture, why
> should they become defective?
>

[olds...@tubes.com]

I have been reading alot of websites about caps. One of them said the
wax coated ones were less leaky (for moisture), than the old plastic
coated ones. I am referring to the ones called "black beauties", that
have color code bands on them.Yet, back in the early 70's, I knew a guy
who was a retired radio-tv repairman as well as a Ham operator, and he
used to say those "black beauties" were far better than the wax ones.
(as well as the other plastic encased ones with the numbers on them
instead of the color bands).

That's conflicting info. Yet I know that all of them are paper caps.

[olds...@tubes.com]

On Fri, 3 Feb 2017 16:18:02 -0500, Tom Biasi <tomb...@optonline.net>
wrote:

Lets NOT go there.....

In all honesty, I think WE ALL LOST. But we would have lost with either
of the lousy candidates we had to pick from.

Enough politics..... Lets stick to electronics. A lot more fun, and
likely a lot safer too....
I'd rather get zapped by a high voltage power supply than a president
with his fingers on the nuclear botton.

[olds...@tubes.com]

On Fri, 3 Feb 2017 21:12:30 -0000, "Benderthe.evilrobot"

<Benderthe...@virginmedia.com> wrote:

>
><olds...@tubes.com> wrote in message


>>

>> And what are these newer ones made from?
>>
>> I know the mica and ceramic caps are reliable and last almost forever.
>
>I've seen loads of ceramic caps fail - but mostly in TV horizontal scan
>sections where the frequency is over 15kHz and high voltage pulse
>conditions.
>
>This got worse with ever increasing PC monitor resolutions.
>
>AFAICR; mica caps were pretty reliable - in most of the places I found them,
>they were used for precision and a specific tempco.

I could see them failing in the HV sections of ol CRT televisions and
monitors. Alot of stuff seemed to fail at those high voltages.

But in radios and audio amps, they seem darn near fail proof....

[Ralph Mowery]

In article <4a0a9cli8rpk4puap...@4ax.com>,
olds...@tubes.com says...

>
>
>
> By the way, why are all the caps now rated at some oddball figure.
> For example, instead of .05, it's ,047? or instead of .003 it's .0033.
>
> Same for the 'lytics instead of 30mf, they are 33mf and so on.....
>
>

Capacitors such as .047 have been around a long time. I don't know why
it is such an odd value as I doubt the extra .003 would be noticable in
the circuits most of them are used in. As the tollorance on most of the
electrolytics are very broad I don't understand the odd values either.

The capacitors operating at 100 KHz and over are in the switching
supplies that are most often used now. That puts a lot of strain on
them that the old 60 Hz didn't.

I have started working on some of the surface mounted devices. It does
take different equipment, but not hard to replace the bad components in
most cases. You just have to invest in a stereo mcroscope
for about $ 200 and a hot air rework station. For just the hobbiest
there are some that have the hot air bun and soldering iron for less
than $ 100. Tweezers instead of needle nose and very small solder and
liquid flux. Lots of good info and how to on youtube.

I only started doing the SMD after I retired at 62.

I did put together my computers up to about 10 years ago. Then found I
could get a used one off ebay for almost nothing that will do what I
want. That is almost less than MS wants for some of the operating
systems and the used ones have the operating system on them.

[Jeff Liebermann]

On Fri, 03 Feb 2017 13:39:02 -0500, cl...@snyder.on.ca wrote:

>On Fri, 03 Feb 2017 09:32:07 -0800, Jeff Liebermann <je...@cruzio.com>
>wrote:

>>In a previous life, I tried to design a "warranty timer" into a
>>product. Actually, it was suppose to accumulate and display the
>>amount of time that the unit had been powered on to help establish
>>maintenance intervals. In previous products, a mechanical
>>counter-timer was used, but for this version, it was deemed too big
>>and expensive.
>><http://www.alliedelec.com/images/products/Small/70132720.jpg>
>>I found a company that made an electrochemical equivalent. It was
>>housed in a glass cylinder, similar to a common 3AG glass fuse. Inside
>>was some chemical solution. When a few volts of DC was applied,
>>electrolytic action caused one end to slowly turn dark, thus
>>indicating the amount of time that the DC was applied. Sorry, but I
>>couldn't find the vendor or an equivalent online. When the required
>>maintenance was performed, the indicator would be replaced as it could
>>not be reset.

> Something like a coulometer???

Sorta. The timer was basically a miniature electroplating bath, which
used a the current flow to move ions of something, from one end of a
glass cylinder to the other. A coulomb is 1 amp for 1 second and can
count both electrons and ions, as in the bath.
<http://www.electrolytics.org/faradaysLaw.html>
I have a box buried somewhere with the project notes which might have
the data sheet. Meanwhile, I think I may have found the patent, or
rather a later patent as the one I used was in about 1976:
<https://www.google.com/patents/US6198701>
I'll dig through the citations later...

[Dave Platt]

In article <MPG.32fed7a04...@news.east.earthlink.net>,

Ralph Mowery <rmower...@earthlink.net> wrote:

>Capacitors such as .047 have been around a long time. I don't know why
>it is such an odd value as I doubt the extra .003 would be noticable in
>the circuits most of them are used in. As the tollorance on most of the
>electrolytics are very broad I don't understand the odd values either.

If you look at the standard values used for resistors and capacitors
and inductors, you can see that they tend to be spaced in a way which
creates something approximating a geometric ratio - that is, each
value in the series is 1-point-something times the previous value.
The higher-precision value "kit" has a total of 24 values over each
decade. The common lower-precision value kit has six values (every
fourth, from the 24-value higher-precision range).

The relationships aren't exact - 0.047 would be 0.046415... and
some of the other "traditional" values are even further off of the
geometric curve. But, that's the basics of it.

I imagine that when picking the values which would go in the
lower-precision set, it was easier to just choose the same nominal
values as were used in the higher-precision set, and specify a lower
tolerance (e.g. +/- 10% for a cheap film cap, or +100/-20 for a
'lytic).

[Jeff Liebermann]

On Fri, 03 Feb 2017 16:38:26 -0600, olds...@tubes.com wrote:

>On Thu, 02 Feb 2017 18:36:08 -0800, Jeff Liebermann <je...@cruzio.com>
>wrote:

>>>And what are these newer ones made from?
>>
>>For electrolytics, try polymer caps:
>><https://en.wikipedia.org/wiki/Polymer_capacitor#Lifetime.2C_service_life>
>><http://www.mouser.com/pdfdocs/Panasonic_Capacitors_WP_final.PDF>

>So, what are the BEST ones? For example, I am getting a Hallicrafters
>sx-99 radio, to recap it, what should I use for the small caps (not
>electrolytics)? Should I use the "orange drops", or is there something
>better? I'd rather spend a few bucks more and get the best.

I'll defer to the those from the antique radio forum, who have more
experience with this than me.

I have helped various friends rebuild old HF radios. I tend to
replace parts involving RF with parts that have the same temperature
coefficient. So, mica caps get replaced with silver mica caps.
Ceramics get replaced by ceramics of approximately the same value,
voltage, and tempco. Film caps are potentially a problem, but I've
seen few of those in old tube radios. Bumble bee, black beauty, and
orange drop caps are junk. There's no temperature coefficient
involved with those, so just whatever I can find that has similar
values in polycarbonate or polypropylene. This should help:
<http://www.audioasylum.com/forums/set/messages/7/75075.html>

>By the way, why are all the caps now rated at some oddball figure.
>For example, instead of .05, it's ,047? or instead of .003 it's .0033.

Get out your calculator and estimate the acceptable range of values
based on the tolerance. For example, a 0.047uF +/- 10% cap can vary
between 0.042 and 0.052uF. Therefore, a 0.050uF is just fine.
Actually, if you measure the caps involved with an LRC meter, you'll
find that they vary well outside of the original specifications. Just
because a capacitor is marked +/-10% doesn't mean that the circuit
requires the same tolerance range.

>Same for the 'lytics instead of 30mf, they are 33mf and so on.....

Most cheapo electrolytics are +100% -20%. So for 30uF, anything
between 60uF and 24uF should work. Again, electrolytics are not that
critical (or very accurate). Occasionally, there will be an
electrolytic in some kind of audio filter that has to be fairly
accurate. You can use the schematic to find those. The rest (power
supply, decoupling, interstage audio coupling, cathode bypass, etc),
can be fairly loose with the tolerances.

>>Not all ceramics are that reliable. MLCC (multi-layer ceramic caps)
>>are rather fragile and microphonic.
>
>What do those look like? Are they the ones with colored dots that look
>like dominos? (But I think those are mica caps, if I'm not mistaken).

You won't find any MLCC caps in tube radios. You'll find them in
computah equipment in the form of large SMT chip caps, sometimes with
leads and dipped in epoxy:
<https://www.google.com/search?q=mlcc+capacitor&tbm=isch>
The caps are evil and fragile. They vary in capacitance with
mechanical pressure and make a tolerable capacitance microphone. Touch
one end, but not the other, with a soldering iron, and the temperature
differential will cause internal cracking and eventually a short.

>I remember those squarish brown ones with the leads on the bottom, those
>were supposed to be superior. (Silver mica, maybe?)

Silver mica. They're very good parts and rarely die unless you cram
too much power through them as in a transmitter.
<https://www.google.com/search?tbm=isch&q=silver+mica+capacitors>
Watch out for the tempco on those. It's printed on the case as NPO,
N750, N1500, Y5V, Y5P, etc.

>And the round ceramics were said to be good too.

Those are called "disc ceramic" capacitors:
<https://www.google.com/search?tbm=isch&q=disc+ceramic+capacitor>
Same warnings are silver mica.

>>>A for electrolytic caps, it seems that the newer ones have a much
>>>shorter life than the old ones did.
>>
>>Nope. The old ones filtered at 120 Hz. The new caps filter at 100 to
>>300 KHz. Internal dissipation follows frequency.

>Can you explain that. I dont understand...
>(I would think that a 'lytic in a power supply would only need to filter
>at 120hz, or would some filter at 60hz also, depending on the
>configuration?

Well, ok. I don't know of any tube radios that use switching power
supplies, so yes, the highest frequency a tube radio power supply will
see is 120 Hz. However, you comment was "for electrolytic caps, it

seems that the newer ones have a much shorter life than the old ones

did". By "newer one's", I assumed newer capacitors in newer circuits,
namely switching power supplies. My guess(tm) is that newer
capacitors will have the same long life as the originals (20+ years)
when used as a replacement in a 120 Hz power supply.

>I guess going back to the tube stuff makes me feel young again!

Sigh. My collection of test equipment looks more like a museum than a
working test bench. I also find myself fixing 40+ years old test
equipment as I do fixing radios etc. Looking at the old stuff, all it
does is make me feel old and tired.

Good luck.

[Jeff Liebermann]

On Fri, 03 Feb 2017 16:50:33 -0600, olds...@tubes.com wrote:

>I have been reading alot of websites about caps. One of them said the
>wax coated ones were less leaky (for moisture), than the old plastic
>coated ones. I am referring to the ones called "black beauties", that
>have color code bands on them.Yet, back in the early 70's, I knew a guy
>who was a retired radio-tv repairman as well as a Ham operator, and he
>used to say those "black beauties" were far better than the wax ones.
>(as well as the other plastic encased ones with the numbers on them
>instead of the color bands).
>
>That's conflicting info. Yet I know that all of them are paper caps.

Nope. The black beauty caps are di film dielectric, which is a
sandwich of mylar and paper. I think they might have been injected
with oil after assembly, but I'm not certain. You must have missed
something in your youth as everyone I knew that was fixing TV's would
break one open to see what was inside.

The preceding caps were bumble bee caps, which were oiled paper
dielectric. The succeeding caps were orange drop caps which are
metalized mylar dielectric.

[Ralph Mowery]

In article <vnhfmd-...@coop.radagast.org>, dpl...@coop.radagast.org
says...

I had forgotten that the resistors were valued at some math function.
Did not know the capacitors and inductors were the same, but seems
reasonable.
As pointed out, almost nothing in electronic components is exact for
normal circuits.

[Nick Danger]

On 2/3/2017 4:18 PM, Tom Biasi wrote:

> Get off of it. You lost.

Sorry that you totally missed the point. Losing has NOTHING to do with
it. The current president would be just as great of a danger to the
country and world if he were a Democrat. Creating an additional nuclear
threat in today's unstable world was not the smartest thing to do.

You won -- but what did you win?

A vindictive, vengeful, thin-skinned, unstable*, erratic* person with
his finger on the nuclear button. Sounds like a "win" to me.

NOT!

* BTW, these two words were used by the Wall Street Journal when
describing the current president.

[Carter]

On 2/3/2017 5:45 PM, Tom Biasi wrote:

> It's a very complex issue. Your feelings are just that, yours.

Sorry, personal, individual "feelings" has NOTHING to do with moving the
Doomsday Clock ahead. The whole world might take exception, do ya think?

[analogdial]

olds...@tubes.com wrote:


>
> I have been reading alot of websites about caps. One of them said the
> wax coated ones were less leaky (for moisture), than the old plastic
> coated ones. I am referring to the ones called "black beauties", that
> have color code bands on them.Yet, back in the early 70's, I knew a guy
> who was a retired radio-tv repairman as well as a Ham operator, and he
> used to say those "black beauties" were far better than the wax ones.
> (as well as the other plastic encased ones with the numbers on them
> instead of the color bands).
>
> That's conflicting info. Yet I know that all of them are paper caps.

In my opinion, the Black Beauties with color bands on them are bad news.
Worse than wax dipped paper caps. They crack, leak oil and sometimes
fail hard -- short circuit. As far as I know, all the Black Beauties
with bands are oil filled.

I've seen old 50s magazines with full page ads claiming wonderful things
for the oil filled Black Beauties and it sure seemed like a good idea.
Steel can paper in oil caps are much more reliable than wax dipped
paper caps, why not paper in oil in a plastic tube? Didn't work out
that way, I don't know why. Maybe the plastic outgassed something nasty
into the cap. Some of the paper in oil Black Beauties had standard
numeric marking rather than bands. The paper in oil Black Beauties can
be identified by a soldered lead on one side of the cap.

The second generation Black Beauties were actually OK. They used a
mylar-paper dielectric which held up about as well as all the
advertising promised for the first gen Black Beauties.

But the damage to the reputation of the Black Beauty had been done and
the Orange Drop became Sprague's high end film cap.

[Phil Allison]

Jeff Liebermann wrote:

>
> >A for electrolytic caps, it seems that the newer ones have a much
> >shorter life than the old ones did.
>
> Nope. The old ones filtered at 120 Hz. The new caps filter at 100 to
> 300 KHz. Internal dissipation follows frequency.
>
>

** Complete bollocks.

Electro cap dissipation is lower at high frequencies cos the ESR is lower at such frequencies.

The no 1 reason for short lifspan is being sited next to heat sources, like power resistors and heatsinks.

The no 2 reason is bad manufacture by no name brands in China etc.


..... Phil

[olds...@tubes.com]

On Fri, 03 Feb 2017 16:40:48 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

>On Fri, 03 Feb 2017 16:50:33 -0600, olds...@tubes.com wrote:
>
>>I have been reading alot of websites about caps. One of them said the
>>wax coated ones were less leaky (for moisture), than the old plastic
>>coated ones. I am referring to the ones called "black beauties", that
>>have color code bands on them.Yet, back in the early 70's, I knew a guy
>>who was a retired radio-tv repairman as well as a Ham operator, and he
>>used to say those "black beauties" were far better than the wax ones.
>>(as well as the other plastic encased ones with the numbers on them
>>instead of the color bands).
>>
>>That's conflicting info. Yet I know that all of them are paper caps.
>
>Nope. The black beauty caps are di film dielectric, which is a
>sandwich of mylar and paper. I think they might have been injected
>with oil after assembly, but I'm not certain. You must have missed
>something in your youth as everyone I knew that was fixing TV's would
>break one open to see what was inside.
>
>The preceding caps were bumble bee caps, which were oiled paper
>dielectric. The succeeding caps were orange drop caps which are
>metalized mylar dielectric.

In my youth, the most common caps I replaced were 'lytics. Next in line
were wax coated tubular paper caps. Only once do I remember replacing a
"black beauty". That was because it had a crack down on side of it,
which tells me that it was likely bad, and if it wasn't, I knew it
needed to be replaced anyhow, before it did absorb moisture and fail.
I did replace a few ceramic disks, but that was bcause I broke them
while unsoldering other stuff.

[olds...@tubes.com]

On Fri, 3 Feb 2017 22:05:48 -0000, "Benderthe.evilrobot"
<Benderthe...@virginmedia.com> wrote:

>>
>> True. But the reason to replace them ALL is that if you only replace the
>> one(s) causing a problem, another will fail later, then another still
>> later. It is much easier to do them all at once than to have to repair
>> the same unit over and over as they fail one after another. Been there,
>> done that.
>
>So have I.
>

I can totally understand what you are saying. However, I am not so sure
about whether I would want to replace all of them in certain parts of a
radio or tv. Here are my thoughts on this.

Lets take my Hallicrafters SX-99 (which I paid for but dont have yet).
That radio is 62 years old. (made in 1955). The seller said it works
fine, (and I was sent a video of it working. I did detect a very slight
hum. (But the video's audio is not the greatest).

So, as soon as I get it and play around with it, I will replace the
electrolytics in the power supply and any other 'lytics (if there are
others). Even if there is no hum, I'd replace them, just based on age.

However, this is a working radio. I ask myself if I really want to
replace all the other (small) caps. [Then I say to myself.... if it
works, dont fix it].

But, I know there are caps in specific circuits more likely to fail,
than in other circuits. Those would be caps connected to the high plate
voltages, especially at the audio output tubes and in the power supply.
I also know that if those short out, they can damage other parts, such
as tubes, resistors, and more. So, I would likely consider replacing
those. I might even consider replacing ALL the caps in the power supply,
and all audio stages, and feel safe doing that, since those caps are not
real critical as far as affecting the overall performance of the radio,
even if the new caps are a little different in their capacitance.

Where I do NOT feel comfortable changing them, are in all RF and IF
stages. The reason is that I know that a cap/coil circuit plays a big
part in the inductance, which affects the radio alignment. I am not
equipped to align the radio coils, and would prefer to leave them alone,
as long as the radio is getting good reception.

I also know that those RF and IF stages do not operate on as high
voltages as do the audio output stages. So, once again, I ask myself,
"Do I really want to risk throwing this radio out of alignment, when
it's working fine, and knowing those caps are not as likely to fail".

I answer myself "Probably not".... (As long as the radio is working
well, dont screw up a good thing.... Then too, if the caps in those
circuits are .05 or .003, I WANT a .05, not a .047. (And it seems that
.05 is no longer made).

So, if I'm satisfied with the performance of this radio, I will replace
the 'lytics regardless. I may also replace all caps AFTER the volume
control, as well as all caps in the power supply. But I will likely NOT
touch any caps in the RF and IF stages.

That's my thinking on all of this right now. Not just for this radio,
but anything..... Now, if it were simply an audio amplifier, I'd likely
replace all the caps, because audio is not all that critical.

[Foxs Mercantile]

On 2/4/2017 4:28 AM, olds...@tubes.com wrote:
> Lets take my Hallicrafters SX-99 (which I paid for but don't have

> yet). That radio is 62 years old. (made in 1955). The seller said
> it works fine, (and I was sent a video of it working. I did detect
> a very slight hum. (But the video's audio is not the greatest).
>

> However, this is a working radio. I ask myself if I really want to
> replace all the other (small) caps. [Then I say to myself.... if it
> works, dont fix it].

To quote a good friend of mine, "There are only two kinds of paper
dielectric capacitors. Those that are bad, and those that are going
to be bad."

> Where I do NOT feel comfortable changing them, are in all RF and IF
> stages.

The paper caps in the RF and IF stages are bypassing and coupling
capacitors. They need to be changed as well.

> I answer myself "Probably not".... (As long as the radio is working

> well, don't screw up a good thing.... Then too, if the caps in those

> circuits are .05 or .003, I WANT a .05, not a .047. (And it seems
> that .05 is no longer made).

"Working" is a subjective thing. Known failure prone parts are just
a time bomb waiting to convert working to not working. And possibly
causing collateral damage when they fail.

Back then, they liked "round numbers." Then the industry standardized
on incremental changes.
As a matter of course, .02 now is .022, .03 is .033 and .05 is .047.
Unless you're playing with tuned audio filters, the difference is
statistically zero.







--
Jeff-1.0
wa6fwi
http://www.foxsmercantile.com

[Tom Biasi]

No

[jurb...@gmail.com]

>"I found a company that made an electrochemical equivalent. It was
housed in a glass cylinder, similar to a common 3AG glass fuse. Inside
was some chemical solution. When a few volts of DC was applied,
electrolytic action caused one end to slowly turn dark, thus
indicating the amount of time that the DC was applied. Sorry, but I
couldn't find the vendor or an equivalent online. When the required
maintenance was performed, the indicator would be replaced as it could
not be reset. "

They used something similar in time lapse video recorders. When those links or whatever went, you are required to replace the video head.

[Michael Black]

On Sat, 4 Feb 2017, olds...@tubes.com wrote:

> On Fri, 3 Feb 2017 22:05:48 -0000, "Benderthe.evilrobot"
> <Benderthe...@virginmedia.com> wrote:
>
>>>
>>> True. But the reason to replace them ALL is that if you only replace the
>>> one(s) causing a problem, another will fail later, then another still
>>> later. It is much easier to do them all at once than to have to repair
>>> the same unit over and over as they fail one after another. Been there,
>>> done that.
>>
>> So have I.
>>
>
> I can totally understand what you are saying. However, I am not so sure
> about whether I would want to replace all of them in certain parts of a
> radio or tv. Here are my thoughts on this.
>
> Lets take my Hallicrafters SX-99 (which I paid for but dont have yet).
> That radio is 62 years old. (made in 1955). The seller said it works
> fine, (and I was sent a video of it working. I did detect a very slight
> hum. (But the video's audio is not the greatest).
>
> So, as soon as I get it and play around with it, I will replace the
> electrolytics in the power supply and any other 'lytics (if there are
> others). Even if there is no hum, I'd replace them, just based on age.
>
> However, this is a working radio. I ask myself if I really want to
> replace all the other (small) caps. [Then I say to myself.... if it
> works, dont fix it].
>

YOU ask around about the radio. There's a point where capacitors got
better, so the bypass capacitors may not need replacing. With some old
radios, it even happened during the production run, so the specific radio
early in the run may need the capacitors replaced, while later the
capacitors were better and don't need replacing.

SOme specific radios may have some problem that is common, so there'll be
warnings "change this capacitor right away, or else it may take other
things with it". Those may not be that the capacitor is likely to fail,
but that if the capacitor fails, it can do damage.

SOme vintage and/or models of radios suffer because the capacitors inside
the IF transformers go bad over time. Asking about the radio will uncover
that sort of thing.

There were periods when a brand of capacitor came along and got heavy use,
only later it's discovered that they don't have long life. It's those
that are the issue, not "all capacitors".

>
> Where I do NOT feel comfortable changing them, are in all RF and IF
> stages. The reason is that I know that a cap/coil circuit plays a big
> part in the inductance, which affects the radio alignment. I am not
> equipped to align the radio coils, and would prefer to leave them alone,
> as long as the radio is getting good reception.
>

But those low value capacitors are the ones least likely to go bad. Any
capacitor can go bad, but generally this is about old types of capacitors.
Nobody uses paper capacitors anymore, but those were used for audio
coupling and bypass capacitors decades ago, and not only can go bad, but
have limitations based on how paper capacitors are made.

Small value capacitors (like below .001uF) are much more likely to be
ceramic or mica, which generally are okay, at least after a certain point
in time. I don't think those are included in the "change all the
capacitors" except if the radio is really old, or a specific model has
some known problem. Yes, if you change the low value capacitors, you risk
upsetting alignment or calibration, and you may inadvertently shift wiring
that needs to stay where it is.

Any component can go bad. This is about doing most of it all at the same
time because once the radio is apart most of the work is done. And some
capacitors are way more likely to give trouble.

Michael

[Michael Black]

And with names like "Black Beauty" and "Orange Drop", who would question
at the time that they weren't good products?

Michael

[olds...@tubes.com]

On Sat, 4 Feb 2017 12:10:54 -0500, Michael Black <et...@ncf.ca> wrote:

>> However, this is a working radio. I ask myself if I really want to
>> replace all the other (small) caps. [Then I say to myself.... if it
>> works, dont fix it].
>>
>YOU ask around about the radio. There's a point where capacitors got
>better, so the bypass capacitors may not need replacing. With some old
>radios, it even happened during the production run, so the specific radio
>early in the run may need the capacitors replaced, while later the
>capacitors were better and don't need replacing.
>
>SOme specific radios may have some problem that is common, so there'll be
>warnings "change this capacitor right away, or else it may take other
>things with it". Those may not be that the capacitor is likely to fail,
>but that if the capacitor fails, it can do damage.
>

What you are saying here is true for almost everything produced. All
cars have certain common problems specific to the brand/model. Same for
other machinery, and for electronics and even plumbing faucets and so
on...

I would like to find out what problems are specific to the Hallicrafters
SX-99. Where is a good place to look?

>SOme vintage and/or models of radios suffer because the capacitors inside
>the IF transformers go bad over time. Asking about the radio will uncover
>that sort of thing.
>
>There were periods when a brand of capacitor came along and got heavy use,
>only later it's discovered that they don't have long life. It's those
>that are the issue, not "all capacitors".
>

I'd be interested in which of the old caps were known to have "issues".
or to fail. Sure, they are all old (in any tube equipmnent), and they
are paper caps, which are no longer made, but I'm sure some brands were
better or worse than others.
And just because newer caps are made from plastics rather than paper,
does not necessarily make them better. Plastics can have issues too. Not
to mention that everything made today is made for a short lifespan.
Considering that, if most of the old paper caps still work, 50, 60, or
70 years later, they obviuosly were not poorly made or a poor design.
I always say, "New does not necessarily mean Better". Today, this is
quite apparent in a lot of things. Old cars far outlast the new ones,
old homes were built better than new ones, and while many will disagree,
I'll take Windows XP, or even Windows 98, (I use both) any day over
Windows 8.x or 10. So, often times, new is NOT better and sometimes it's
worse.

>> Where I do NOT feel comfortable changing them, are in all RF and IF
>> stages. The reason is that I know that a cap/coil circuit plays a big
>> part in the inductance, which affects the radio alignment. I am not
>> equipped to align the radio coils, and would prefer to leave them alone,
>> as long as the radio is getting good reception.
>>
>But those low value capacitors are the ones least likely to go bad. Any
>capacitor can go bad, but generally this is about old types of capacitors.
>Nobody uses paper capacitors anymore, but those were used for audio
>coupling and bypass capacitors decades ago, and not only can go bad, but
>have limitations based on how paper capacitors are made.
>

One thing I've noticed is that all caps seem to be a lot smaller these
days. (For the same value and voltage). I'm taking a wild guess, when I
figure this is because paper was thicker than the plastic materials used
today. But is this really better? Thinner means that high voltages have
a shorter distance to arc across, causing a short. And which of these
plastics will still be good in 5 years, or 20 or 50 years? Paper caps
seem to have passed the test of time. We wont know if these newer
materials pass the test of time or not, until we get there.

I'm not saying any material is better or worse, because I am only
guessing, but it does appear that old technology, made from things like
steel, wood, brick and other natural materials, are lasting longer than
most plastics. It's like when Chevy started using plastic timing gears
in their engines, which soon proved to fail much sooner than the old
steel ones.

So, are the newer caps really better? I dont know... I can only go with
the advice of those in the repair end of the business, and that is all
based on time. The manufacturers always claim they have a better
product, because they want to make sales, so their words mean nothing.

When I finally do get to recapping this radio, I am still clueless what
type of modern caps to use. In the old days, they were all paper caps,
and it just came down to knowing which manufacturer had a better
reputation. But now there are multiple different plastics in use, which
makes it a lot harder to know what to use.

[olds...@tubes.com]

On Sat, 4 Feb 2017 08:56:42 -0600, Foxs Mercantile <jda...@att.net>
wrote:

>> However, this is a working radio. I ask myself if I really want to
>> replace all the other (small) caps. [Then I say to myself.... if it
>> works, dont fix it].
>
>To quote a good friend of mine, "There are only two kinds of paper
>dielectric capacitors. Those that are bad, and those that are going
>to be bad."

Everything will fail some time in the future..... It dont matter what it
is. But will it be tomorrow, or 100 years from now?
So, somtime in the future, every paper cap, as well as every modern cap
is going to fail. But at my age, I only have to think 2 or maybe 3
decades at most into the future. After that, it's someone else's
problem.

[Nick Danger]

On 2/4/2017 12:13 PM, Michael Black wrote:

> And with names like "Black Beauty" and "Orange Drop", who would question
> at the time that they weren't good products?
>
> Michael

I know from years of personal experience that "Black Beauties" were
*notoriously* bad. However, I always thought the Orange Drops were
pretty good. Not so?

[olds...@tubes.com]

On Sat, 4 Feb 2017 12:13:30 -0500, Michael Black <et...@ncf.ca> wrote:

>And with names like "Black Beauty" and "Orange Drop", who would question
>at the time that they weren't good products?
>
> Michael

It could have been PURPLE HAZE! <LOL>

[olds...@tubes.com]

On Sat, 4 Feb 2017 14:39:13 -0500, Nick Danger <ni...@third.eye.net>
wrote:

Back in the mid 60's into the 70s, I was told the black beauties were
one of the better caps made. But after reading a lot of websites about
caps, it now appears they have proven to be bad.

On the other hand, back then, and still now, it appears that the orange
drops were highly rated, as well as being some of the most costly.
Except for one poster in this thread, I have never heard anything bad
about them. One of the websites I was reading said they are one of the
brands to consider for recapping, but went on to say that there are
cheaper caps which work just as well.

Back then, I used a lot of orange drops as replacements and I never had
problems with them. I will say that I did not always like the fact that
their wires come out of the bottom, since for non-circuit board
applications, they were a little clumbsy to fit into some places, versus
the tubular caps with wires on the ends.

[Benderthe.evilrobot]

"Ralph Mowery" <rmower...@earthlink.net> wrote in message
news:MPG.32fed7a04...@news.east.earthlink.net...

The preferred values were worked out so you can fill the spaces between them
with series/parallel combinations.

[Benderthe.evilrobot]

<olds...@tubes.com> wrote in message
news:1o2a9cp0ormk0jqmm...@4ax.com...

I've never seen mica in TV or monitor HV sections - and I can't think of any
advantage from using them for that.

[Benderthe.evilrobot]

<olds...@tubes.com> wrote in message
news:k09b9cd4005htcn0h...@4ax.com...

> On Fri, 3 Feb 2017 22:05:48 -0000, "Benderthe.evilrobot"
> <Benderthe...@virginmedia.com> wrote:
>
>>>
>>> True. But the reason to replace them ALL is that if you only replace
>>> the
>>> one(s) causing a problem, another will fail later, then another still
>>> later. It is much easier to do them all at once than to have to repair
>>> the same unit over and over as they fail one after another. Been there,
>>> done that.
>>
>>So have I.
>>
>
> I can totally understand what you are saying. However, I am not so sure
> about whether I would want to replace all of them in certain parts of a
> radio or tv. Here are my thoughts on this.
>
> Lets take my Hallicrafters SX-99 (which I paid for but dont have yet).
> That radio is 62 years old. (made in 1955). The seller said it works
> fine, (and I was sent a video of it working. I did detect a very slight
> hum. (But the video's audio is not the greatest).

The whole thread is based on a bit of a generalisation - you have to apply a
bit of common sense.

Generally; coupling and decoupling caps close to tubes that run hot are good
candidates.

Caps that may affect tuned circuits tend to be close to small signal tubes
that run much cooler.

[olds...@tubes.com]

On 03 Feb 2017 02:13:07 GMT, Jim Mueller <wron...@nospam.com> wrote:

>The old electrolytic capacitors you are talking about don't sound like
>the oil filled variety. Indeed, if they are electrolytic, they aren't
>oil filled. Oil filled capacitors aren't polarized and many of them are
>good today. They were the high quality capacitors used in military and
>

I always thought those were oil filled, but I see I was wrong. I looked
on the web too, and it appears that most of them were filled with a
boric acid solution, which is not really harmful. They all had the tiny
vent hole in the top, and had a large threaded mounting on the bottom,
which required a sizable nut.

It's been years since I touched one of them. I only remember (vividly)
getting sprayed by one of them many years ago. It was boiling hot and it
hurt like hell. After that incident, I just replaced them before I even
pluggd in anyting that had that type of cap. (Or put a soup can over
them temporarily) They were probably the worst caps ever made.

Here is a pic I found online.
https://antiqueradio.org/art/Midwest18-3621.jpg

[olds...@tubes.com]

On Fri, 03 Feb 2017 16:26:47 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

>Sigh. My collection of test equipment looks more like a museum than a
>working test bench. I also find myself fixing 40+ years old test
>equipment as I do fixing radios etc. Looking at the old stuff, all it
>does is make me feel old and tired.

Thats all I have too, and some of it has not been used in years and may
likely no longer work. I'm not looking to get heavily into this stuff
anymore. My eyes are not that good anymore either. I just want a project
or two so I have something useful to do indoors during these long cold
midwest winters. In the warm weather I am mostly outdoors working on
building stuff and fixing antique machinery. But in winter it's either
stare at the lousy programming on tv, waste a lot of time reading (a lot
of crap) on the internet, or do something with rewards, which means
restoring some ancient electronics. I'll never fit in with the current
cellphone/facebook crowd.....

---
I overheard a young guy bragging about his new Iphone. I walked up and
told him I had something better, AN EARPHONE! :)

[Nick Danger]

>
>
>> On 2/4/2017 12:13 PM, Michael Black wrote:
>>
>>> And with names like "Black Beauty" and "Orange Drop", who would question
>>> at the time that they weren't good products?
>>>
>>> Michael

On Sat, 4 Feb 2017 14:39:13 -0500, Nick Danger <ni...@third.eye.net>
wrote:

>> I know from years of personal experience that "Black Beauties" were
>> *notoriously* bad. However, I always thought the Orange Drops were
>> pretty good. Not so?

On 2/4/2017 2:49 PM, olds...@tubes.com wrote:

> Back in the mid 60's into the 70s, I was told the black beauties were
> one of the better caps made. But after reading a lot of websites about
> caps, it now appears they have proven to be bad.

I discovered that from experience. BBs were notoriously leaky, both
electrically and physically.

> On the other hand, back then, and still now, it appears that the orange
> drops were highly rated, as well as being some of the most costly.

I never worried about the cost -- I always figured the labor to put in a
good one or to put in junk was the same.

> Except for one poster in this thread, I have never heard anything bad
> about them.

Ditto and thus the reason for my original question.

> One of the websites I was reading said they are one of the
> brands to consider for recapping, but went on to say that there are
> cheaper caps which work just as well.
>
> Back then, I used a lot of orange drops as replacements and I never had
> problems with them.

True in my case too. I also used them along with 88 mh toroidal
telephone loading coils to make Mark / Space filters for radio teletype
decoders --and the orange drops were very stable. (I know, I'm dating
myself in this day and age of software/sound card RTTY decoders). :-)

[Foxs Mercantile]

On 2/4/2017 4:58 PM, Nick Danger wrote:
> True in my case too. I also used them along with 88 mh toroidal
> telephone loading coils to make Mark / Space filters for radio
> teletype decoders --and the orange drops were very stable. (I
> know, I'm dating myself in this day and age of software/sound
> card RTTY decoders). :-)

You and me brother. You and me. ;-)
As a side note, I'm still playing with RTTY and using a real
machine. A Lorenz Lo-15c. ;-)

[Foxs Mercantile]

On 2/4/2017 1:49 PM, olds...@tubes.com wrote:
> Back then, I used a lot of orange drops as replacements and
> I never had problems with them. I will say that I did not
> always like the fact that their wires come out of the bottom,
> since for non-circuit board applications, they were a little

> clumsy to fit into some places, versus the tubular caps with
> wires on the ends.

They are good parts. A bit over priced however. And yes, radial
leads instead of axial. Can be an issue when you're replacing
axial lead parts.

[Jim Mueller]

Progress is incremental. Those capacitors had major advantages over what
came before. The "dry" electrolytics that followed them had further
advantages. That's how things go.

--
Jim Mueller wron...@nospam.com

To get my real email address, replace wrongname with dadoheadman.
Then replace nospam with fastmail. Lastly, replace com with us.

[Jim Mueller]

I think that there is a misunderstanding here. The statement to replace
all the capacitors actually means all the electrolytic and paper
capacitors. Usually ceramic and mica capacitors are still good and
nobody replaces those unless they are proven to be bad.

The paper capacitors in the IF and RF stages need to be replaced even if
the radio "works". Leaky capacitors change the voltages on the tubes
causing them to work at less than their best performance. Also, these
capacitors are used as supply bypasses and AVC filter capacitors. They
do not affect the alignment of the set; the ceramic and mica capacitors
may. Their value is not particularly critical; pick the closest modern
value.

Consider the value issue. If the radio has a .05 uF, 20% capacitor in
it, its actual value can be anywhere from 0.04 uF to 0.06 uF. A modern
0.047 uF 10% capacitor can be between .0423 uF and 0.0517 uF. So the
0.047 uF capacitor can be closer to 0.05 uF than the old one marked with
that value.

As for life expectancy, there was a time in the late '50s and early '60s
when both paper and plastic film capacitors were used. The paper
capacitors I have from that period are universally bad while the plastic
film ones are almost always good. Plastic film has passed the test of
time.

As for what type of plastic film to use, polyester (AKA Mylar) is the
cheapest and has the poorest performance. But it is still better than
the paper capacitors of old so it is suitable for use just about anywhere
a paper capacitor was formerly used. Polycarbonate (no longer made) and
polypropylene are better but more expensive. Polystyrene capacitors are
also very good and inexpensive but are usually seen only in small values
and are frequently not seen at all. They also have the problem that they
melt at lower temperatures than other plastic capacitors and solvents
dissolve them. Still, within their limitations, they are excellent.

[Jim Mueller]

Wow, this thread has really taken off. It's almost like the old days of
Usenet!

[olds...@tubes.com]

On 04 Feb 2017 23:46:23 GMT, Jim Mueller <wron...@nospam.com> wrote:

>On Sat, 04 Feb 2017 15:26:31 -0600, oldschool wrote:
>
>> On 03 Feb 2017 02:13:07 GMT, Jim Mueller <wron...@nospam.com> wrote:
>>
>>>The old electrolytic capacitors you are talking about don't sound like
>>>the oil filled variety. Indeed, if they are electrolytic, they aren't
>>>oil filled. Oil filled capacitors aren't polarized and many of them are
>>>good today. They were the high quality capacitors used in military and
>>>
>>>
>> I always thought those were oil filled, but I see I was wrong. I looked
>> on the web too, and it appears that most of them were filled with a
>> boric acid solution, which is not really harmful. They all had the tiny
>> vent hole in the top, and had a large threaded mounting on the bottom,
>> which required a sizable nut.
>>
>> It's been years since I touched one of them. I only remember (vividly)
>> getting sprayed by one of them many years ago. It was boiling hot and it
>> hurt like hell. After that incident, I just replaced them before I even
>> pluggd in anyting that had that type of cap. (Or put a soup can over
>> them temporarily) They were probably the worst caps ever made.
>>
>> Here is a pic I found online.
>> https://antiqueradio.org/art/Midwest18-3621.jpg
>
>Progress is incremental. Those capacitors had major advantages over what
>came before. The "dry" electrolytics that followed them had further
>advantages. That's how things go.

I know the dry 'lytics were better, I have to ask what came before these
wet ones with the vent hole? I really dont know...

One thing I liked about those wet ones was the threaded nut on the
bottom. Very easy to install and remove! Those twist tabs on the dry
caps in the metal cans tended to break off quite easily, if the cap was
being removed to be reused elsewhere, and if one was soldered, it was
even harder. (generally one was soldered).

[olds...@tubes.com]

On Sat, 4 Feb 2017 17:05:43 -0600, Foxs Mercantile <jda...@att.net>
wrote:

I wonder why they dont make them both radial and axial? I'd think that
it's just a matter of rerouting the wires from the same innards.

[olds...@tubes.com]

On 05 Feb 2017 00:21:42 GMT, Jim Mueller <wron...@nospam.com> wrote:

>I think that there is a misunderstanding here. The statement to replace
>all the capacitors actually means all the electrolytic and paper
>capacitors. Usually ceramic and mica capacitors are still good and
>nobody replaces those unless they are proven to be bad.
>
>The paper capacitors in the IF and RF stages need to be replaced even if
>the radio "works". Leaky capacitors change the voltages on the tubes
>causing them to work at less than their best performance. Also, these
>capacitors are used as supply bypasses and AVC filter capacitors. They
>do not affect the alignment of the set; the ceramic and mica capacitors
>may. Their value is not particularly critical; pick the closest modern
>value.
>

I hear you.....

>Consider the value issue. If the radio has a .05 uF, 20% capacitor in
>it, its actual value can be anywhere from 0.04 uF to 0.06 uF. A modern
>0.047 uF 10% capacitor can be between .0423 uF and 0.0517 uF. So the
>0.047 uF capacitor can be closer to 0.05 uF than the old one marked with
>that value.
>

OK. That makes sense...

>As for life expectancy, there was a time in the late '50s and early '60s
>when both paper and plastic film capacitors were used. The paper
>capacitors I have from that period are universally bad while the plastic
>film ones are almost always good. Plastic film has passed the test of
>time.
>
>As for what type of plastic film to use, polyester (AKA Mylar) is the
>cheapest and has the poorest performance. But it is still better than
>the paper capacitors of old so it is suitable for use just about anywhere
>a paper capacitor was formerly used. Polycarbonate (no longer made) and
>polypropylene are better but more expensive. Polystyrene capacitors are
>also very good and inexpensive but are usually seen only in small values

I see where this can get confusing. I'll consider the polyester (AKA
Mylar), but for the small cost difference, I'd probably prefer the best.
It looks like polypropylene would be that choice.

Do you have any brand names to recommend for these types?
(I will be buying online, there are no electronics stores around here).

>and are frequently not seen at all. They also have the problem that they
>melt at lower temperatures than other plastic capacitors and solvents
>dissolve them. Still, within their limitations, they are excellent.
>

Dont you mean they melt at a *HIGHER* temperature? I cant imagine how
something could melt at a low temp?

Upon reading a URL that somone posted on here, I see where the
audiophliles say that some caps have better sound quality, than others.
On a SW radio, I'm not really looking for "precision sound", but more so
for best performance from the signal coming from the antenna to the
speaker. And while some (or most) of these newer types of caps are made
to be used with modern gear, containing semiconductors, which are the
best choice for old tube stuff. I would think that the caps should mimic
the old paper caps, because that is what these circuits were designed to
use. I know the values of caps are the capcitance (in MF or MMF) and the
voltage. But I know there are other factors that I know nothing about.
Someone mentioned tempco (is that what I read?) in another message in
this thread. What the heck is that?

Either way, I do believe the caps should be similar to the original ones
to work properly. Just made from better materials.


>--
>Jim Mueller wron...@nospam.com

[olds...@tubes.com]

On 05 Feb 2017 00:42:19 GMT, Jim Mueller <wron...@nospam.com> wrote:

>Wow, this thread has really taken off. It's almost like the old days of
>Usenet!

I miss those days. The majority of newsgroups are either dead or filled
with morons or off topic political based fighting and name calling these
days. There were many worthwhile newsgroups that I used to enjoy, and I
wont even go there anymore.

I cant understand where everyone went. I know almost everyon has an
account with that miserable facebook these days (except me), but I cant
say I have ever seen any useful discussions on FB. For the brief time I
did connect to FB, what I saw was just a lot of links to websites
dealing with world affairs, and lots of rude comments about them. Or
pictures of people when they were drunk, with more rude comments.... Not
to mention the 20 or more ads on each page. The day when FB becomes the
entire internet, is the day I pull the plug. (And actually I cant even
use FB if I did want to. My only affordable internet access is still
dialup, because that's all there is in this rural area where I live, and
bloated websites like FB and most of the news media sites wont even load
anymore).

[Foxs Mercantile]

On 2/4/2017 7:25 PM, olds...@tubes.com wrote:
> Do you have any brand names to recommend for these types?
> (I will be buying online, there are no electronics stores
> around here).

I get mine from here:
<http://www.tuberadios.com/capacitors/>

[Bill Burns]

On 2/4/2017 8:49 PM, olds...@tubes.com wrote:
> On 05 Feb 2017 00:42:19 GMT, Jim Mueller <wron...@nospam.com> wrote:
>
>> Wow, this thread has really taken off. It's almost like the old days of
>> Usenet!
>
> I miss those days. The majority of newsgroups are either dead or filled
> with morons or off topic political based fighting and name calling these
> days. There were many worthwhile newsgroups that I used to enjoy, and I
> wont even go there anymore.

Hard to believe r.a.r+p dates back to September 1994. I was one of the
founding members under my email address at the time, bi...@savvy.com

http://fmamradios.com/RESULT-rar+p.txt

-- Bill

[Nick Danger]

> On 2/4/2017 4:58 PM, Nick Danger wrote:
>> True in my case too. I also used them along with 88 mh toroidal
>> telephone loading coils to make Mark / Space filters for radio
>> teletype decoders --and the orange drops were very stable. (I
>> know, I'm dating myself in this day and age of software/sound
>> card RTTY decoders). :-)

On 2/4/2017 6:03 PM, Foxs Mercantile wrote:

> You and me brother. You and me. ;-)
> As a side note, I'm still playing with RTTY and using a real
> machine. A Lorenz Lo-15c. ;-)

Interesting...but I never had what I presume to be a European machine.

Started with a Model 15 KSR, then a Model 32 ASR and finally a Model 28
KSR -- with a home brew digital/electronic replacement for the paper
tape. Today it's all pixels.

[Benderthe.evilrobot]

<olds...@tubes.com> wrote in message
news:52tc9c5c5kjmkfbna...@4ax.com...

> On 04 Feb 2017 23:46:23 GMT, Jim Mueller <wron...@nospam.com> wrote:
>
>>On Sat, 04 Feb 2017 15:26:31 -0600, oldschool wrote:
>>
>>> On 03 Feb 2017 02:13:07 GMT, Jim Mueller <wron...@nospam.com> wrote:
>>>
>>>>The old electrolytic capacitors you are talking about don't sound like
>>>>the oil filled variety. Indeed, if they are electrolytic, they aren't
>>>>oil filled. Oil filled capacitors aren't polarized and many of them are
>>>>good today. They were the high quality capacitors used in military and
>>>>
>>>>
>>> I always thought those were oil filled, but I see I was wrong. I looked
>>> on the web too, and it appears that most of them were filled with a
>>> boric acid solution, which is not really harmful. They all had the tiny
>>> vent hole in the top, and had a large threaded mounting on the bottom,
>>> which required a sizable nut.
>>>
>>> It's been years since I touched one of them. I only remember (vividly)
>>> getting sprayed by one of them many years ago. It was boiling hot and it
>>> hurt like hell. After that incident, I just replaced them before I even
>>> pluggd in anyting that had that type of cap. (Or put a soup can over
>>> them temporarily) They were probably the worst caps ever made.
>>>
>>> Here is a pic I found online.
>>> https://antiqueradio.org/art/Midwest18-3621.jpg
>>
>>Progress is incremental. Those capacitors had major advantages over what
>>came before. The "dry" electrolytics that followed them had further
>>advantages. That's how things go.
>
> I know the dry 'lytics were better, I have to ask what came before these
> wet ones with the vent hole? I really dont know...

When I was a kid, I liked taking old radios to bits. A mains reservoir
electrolytic I "autopsied" had a centre electrode that was sort of like a
curvy column (for maximum surface area) up the middle, the can was the other
electrode, it was completely filled with electrolyte. Another old radio had
a compartment under the one that housed the chassis, it contained a huge
slab flat wound paper capacitor - it must've weighed at least 7lb.

[Benderthe.evilrobot]

"Jim Mueller" <wron...@nospam.com> wrote in message
news:58967016$0$54323$c3e8da3$12bc...@news.astraweb.com...

That's not far different to what I said - certain types of cap you learn
from experience should be regarded as suspect. More reliable types can
deteriorate if they're close to the heat from power tubes. Anything that can
affect RF/IF tuning shouldn't be disturbed unless you know its faulty.

[Foxs Mercantile]

On 2/5/2017 9:36 AM, Nick Danger wrote:
> Interesting...but I never had what I presume to be a European machine.
>
> Started with a Model 15 KSR, then a Model 32 ASR and finally a Model 28
> KSR -- with a home brew digital/electronic replacement for the paper
> tape. Today it's all pixels.

Lorenz Lo-15c
<http://old.fernschreibamt-hausneindorf.de/assets/images/Arbeitsplart_Lo15c.jpg>

I started with a Teletype Model 15 in 1972, then a Model 19 in 1974.
Then got my grubby little hooks into a Model 32. I acquired the
Lorenz in 2007. It used to be in the German Consulate in Los Angeles.

For the terminal units, I started with a used homebrew with the
classic 88 mH toroids. Then graduated to the HAL ST-6000, then the
ST-8000 and currently the ST-8000A.

I'm waiting for the last of the PK-232 boxes to finally die. Because
200 Hz shift is NOT equal to 170 Hz shift. Regardless of what their
manual says.

[Nick Danger]

> On 2/5/2017 9:36 AM, Nick Danger wrote:
>> Interesting...but I never had what I presume to be a European machine.
>>
>> Started with a Model 15 KSR, then a Model 32 ASR and finally a Model 28
>> KSR -- with a home brew digital/electronic replacement for the paper
>> tape. Today it's all pixels.

On 2/5/2017 2:31 PM, Foxs Mercantile wrote:

> Lorenz Lo-15c
> <http://old.fernschreibamt-hausneindorf.de/assets/images/Arbeitsplart_Lo15c.jpg>

quite impressive!

> I started with a Teletype Model 15 in 1972, then a Model 19 in 1974.
> Then got my grubby little hooks into a Model 32. I acquired the
> Lorenz in 2007. It used to be in the German Consulate in Los Angeles.
>
> For the terminal units, I started with a used homebrew with the
> classic 88 mH toroids. Then graduated to the HAL ST-6000, then the
> ST-8000 and currently the ST-8000A.

Wow! Big bucks. HAL made nice equipment -- that I couldn't afford. I had
a W6FFC (Irv Hoff?) ST-6 TU kit, a 3" home brew solid state scope from
73 magazine for a tuning indicator and a W6FFC AFSK unit (for 2 meter
RTTY) all built into a Drake 4-line cabinet to match my Drake 4B line,
Heathkit scope bezel, CRT, mu metal shield and Heath knobs. Was a
avionics guy in the Air National Guard at the time and was able to use
the Airframe sheet metal shop to create the chassis and front panel.

> I'm waiting for the last of the PK-232 boxes to finally die. Because
> 200 Hz shift is NOT equal to 170 Hz shift. Regardless of what their
> manual says.

A PK-232 you say? I used a KAM+ that allowed you to very easily change
speeds (and maybe shifts) on the fly on RTTY. As a matter of fact,
that's how I worked the guy from [Russian] Georgia who was operating in
NORTH Korea on rtty. Everybody was calling him using the US 60 wpm
speed, but I was able to realize he was using the European speed (forgot
what that was), but changed it on the fly, worked him and got the North
Korea QSL to prove it.

73

[Ralph Mowery]

In article <o781rk$ob3$1...@dont-email.me>, ni...@third.eye.net says...

>
>
> Wow! Big bucks. HAL made nice equipment -- that I couldn't afford. I had
> a W6FFC (Irv Hoff?) ST-6 TU kit, a 3" home brew solid state scope from
> 73 magazine for a tuning indicator and a W6FFC AFSK unit (for 2 meter
> RTTY) all built into a Drake 4-line cabinet to match my Drake 4B line,
> Heathkit scope bezel, CRT, mu metal shield and Heath knobs. Was a
> avionics guy in the Air National Guard at the time and was able to use
> the Airframe sheet metal shop to create the chassis and front panel.
>
>

YOu started withe the kit, I could not afford that in the 1980'S.
Wired up a version of the st-6 from a schematic in Ham Radio and the
matching tone generator from the RTTY Journal on a piece of pref board
by hand. I did have a Heathkit counter to adjust the tones. Stuff
looked like crap, but worked very well.

At that time there was about 20 local hams on the 220 FM band.
I still dabble with receiving rtty on the Mod 19 from time to time.

[Foxs Mercantile]

On 2/5/2017 3:17 PM, Ralph Mowery wrote:
> At that time there was about 20 local hams on the 220 FM band.

Heh, I hung out on 145.85 MHz on AM AFSK.

> I still dabble with receiving rtty on the Mod 19 from time to time.

That's a pretty big chunk of "e-waste" let me know when you need to
"properly" dispose of it. ;-)

[olds...@tubes.com]

On Sat, 4 Feb 2017 19:54:04 -0600, Foxs Mercantile <jda...@att.net>
wrote:

>On 2/4/2017 7:25 PM, olds...@tubes.com wrote:
>> Do you have any brand names to recommend for these types?
>> (I will be buying online, there are no electronics stores
>> around here).
>
>I get mine from here:
><http://www.tuberadios.com/capacitors/>

Although they did not list the shipping cost, the cost of the caps is
quite reasonable, and they do have a fairly good selection.
What I am not seeing is any brand name. Who makes them?
Are they US made?

If the shipping is reasonable, I'd likely order from them based on your
referral, but it would be nice to know a little more about them.

[olds...@tubes.com]

On Sun, 5 Feb 2017 19:14:06 -0000, "Benderthe.evilrobot"
<Benderthe...@virginmedia.com> wrote:

>>
>> I know the dry 'lytics were better, I have to ask what came before these
>> wet ones with the vent hole? I really dont know...
>
>When I was a kid, I liked taking old radios to bits. A mains reservoir
>electrolytic I "autopsied" had a centre electrode that was sort of like a
>curvy column (for maximum surface area) up the middle, the can was the other
>electrode, it was completely filled with electrolyte. Another old radio had
>a compartment under the one that housed the chassis, it contained a huge
>slab flat wound paper capacitor - it must've weighed at least 7lb.

That sort of thing I never encountered. That must have been REALLY old!
Most of the stuff I worked on, was mid 40s thru 60s. I had a few of
those old wooden radios that stood about 40" tall and had a round top.
Those were some of the harder ones I tried to work on, and the tubes
were unusual. I know those were the ones that had those wet caps with
the top vent hole. I also recall that the speaker magnet was an
electro-magnet and was also used as a choke for the power supply. Those
were some of the oldest things I worked on.

[Jeff Liebermann]

On Sat, 04 Feb 2017 19:49:33 -0600, olds...@tubes.com wrote:

>I miss those days. The majority of newsgroups are either dead or filled
>with morons or off topic political based fighting and name calling these
>days. There were many worthwhile newsgroups that I used to enjoy, and I
>wont even go there anymore.

The surest sign of success is abuse and pollution. Usenet is
obviously successful.

I wrote this rant on Usenet "personalities" maybe 20 years ago when
observed the same problems you've mentioned:
<http://802.11junk.com/jeffl/crud/genesis.txt>

>I cant understand where everyone went.

Probably Reddit:
<https://www.reddit.com/r/VintageRadios/>
<https://www.reddit.com/r/vintageaudio/>
<https://www.reddit.com/r/audiorepair/>

>I know almost everyon has an
>account with that miserable facebook these days (except me), but I cant
>say I have ever seen any useful discussions on FB.

I have a Facebook account and I'm not afraid to use it. Mostly, I
hang round two local groups that deal with the usual neighborhood
problems. It works fairly well, and much better than the old bulletin
board outside the post office or market. It might work better if I
take the time to learn how to navigate the Facebook maze.

>My only affordable internet access is still
>dialup, because that's all there is in this rural area where I live, and
>bloated websites like FB and most of the news media sites wont even load
>anymore).

Check into alternatives to cable and telco internet. There are plenty
of WISP's (wireless internet service providers).
<http://www.wispa.org/Directories/Find-a-WISP>
Maybe share a wireless backhaul connection with the neighbors. I
setup a few such systems using various backhauls (including
satellite). They were slow and clumsy, but sufficient as the
alternative would have been dialup or no internet.

Also, you can really cut down on the traffic by using the mobile URL's
instead of the usual URL. Try it:
<https://m.facebook.com>
<https://m.google.com>
etc... You may need to install a browser addon that fakes the user
agent string, so that the web pile thinks you're using a smartphone.
<http://www.howtogeek.com/113439/how-to-change-your-browsers-user-agent-without-installing-any-extensions/>
For example:
<https://addons.mozilla.org/en-US/firefox/addon/user-agent-switcher/>
There are others. There are also browser tweaks for dialup:
<http://lifehacker.com/140120/geek-to-live--how-to-survive-a-slow-internet-connection>
Or, you can switch to a text based browser.
<https://en.wikipedia.org/wiki/Text-based_web_browser>
However, I'm not sure it will work with Facebook.


--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[olds...@tubes.com]

On Sun, 05 Feb 2017 13:58:00 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

>On Sat, 04 Feb 2017 19:49:33 -0600, olds...@tubes.com wrote:
>
>>I miss those days. The majority of newsgroups are either dead or filled
>>with morons or off topic political based fighting and name calling these
>>days. There were many worthwhile newsgroups that I used to enjoy, and I
>>wont even go there anymore.
>
>The surest sign of success is abuse and pollution. Usenet is
>obviously successful.
>
>I wrote this rant on Usenet "personalities" maybe 20 years ago when
>observed the same problems you've mentioned:
><http://802.11junk.com/jeffl/crud/genesis.txt>
>
>>I cant understand where everyone went.
>
>Probably Reddit:
><https://www.reddit.com/r/VintageRadios/>
><https://www.reddit.com/r/vintageaudio/>
><https://www.reddit.com/r/audiorepair/>
>

I'll have to look at those. I personally hate web based forums, but that
is mostly bcause on dialup, it takes too long to load the pages. I used
to go ro some of those Yahoo Groups, years ago, but even them have been
taken over by spam trolls and abuse.

>>I know almost everyon has an
>>account with that miserable facebook these days (except me), but I cant
>>say I have ever seen any useful discussions on FB.
>
>I have a Facebook account and I'm not afraid to use it. Mostly, I
>hang round two local groups that deal with the usual neighborhood
>problems. It works fairly well, and much better than the old bulletin
>board outside the post office or market. It might work better if I
>take the time to learn how to navigate the Facebook maze.
>

Some people seem to like FB. I actually had an account for a very short
time. After spending many hours trying to understand how to use it, (and
it's not easy), I made a page for a small non-profit event that I run.
It took less than one week for idiots to ruin it. Nothing posted to it
had anything to do with the topic. It became a place for people to beg
for money, call other people names, discuss politics, and post photos of
themselves drunk. Since I could only work on it from the library or a
local restaurant (using the WIFI), I finally turned the page over to
another member of our group and said here is the group and the password,
FIX THIS. After a week or so, they said that I had not made it limited
enough, and it was beyond fixing. I told them to remove everyone from
the "friends list" except the actual members of our organization.
But even doing that did not seem to stop the abuse of the site (page).
Out of extreme frustration, I deleted the whole thing, and said I would
never touch FB again.

I am a lot more limited than you could imagine. My nearest neighbor is
over a mile away. The nearest small town is 5 miles, the nearest large
city is 55 miles. I can not get a reliable cell phone signal here. To
make a call, I have to either drive up the hill, or (in warm weather), I
may go up on the roof. Because of that, I MUST keep a landline (which
also takes care of my dialup needs). There is no cable. The only way
might be a satellite dish. And that would cost me at least $100 per
month. I dont want the tv part of it. I dont watch much tv and I only
watch ME-TV (oldies). My antenna on the 35 foot tower I made from pipe,
works pretty well for tv, but only gets stations from one direction,
since there's a hill on my other side.

I am going to check on some of these text based browsers and stuff like
that though. At one time, I used a browser called "Off By One", which
only displayed text and pics. But it will not work on any websites using
HTTPS (secured), and many of them are using that now, even wikipedia.

Thanks

[Jim Mueller]

No, polystyrene capacitors have LOWER maximum temperature capability than
most other capacitors; that is one of their limitations. But they have
very low leakage, last forever if not mistreated, and are cheap.

Tempco is shorthand for temperature coefficient. It describes how much
the capacitance changes as temperature changes. Some capacitors change
very little (for example C0G ceramics), others change a LOT (Z5U
ceramics).

[Jim Mueller]

On Sat, 04 Feb 2017 18:53:53 -0600, oldschool wrote:

> snip

> I wonder why they dont make them both radial and axial? I'd think that
> it's just a matter of rerouting the wires from the same innards.

No market. Everything now is built on PC boards and axial lead parts
take up too much room. Some axial lead parts are getting hard to get.

[Jeff Liebermann]

On Sun, 05 Feb 2017 16:47:14 -0600, olds...@tubes.com wrote:

>I am a lot more limited than you could imagine.

Agreed. You've given up before you've even started looking for a
solution. We have about 5 small and one large wireless ISP's in my
area that provide reliable service for your situation.

>My nearest neighbor is over a mile away.

Duz this neighbor have high speed internet? If so, a point to point
wireless link will get you internet.

>The nearest small town is 5 miles,

Can you "see" this small town from your rooftop? From a nearby
hilltop on your property? From the top of a tree or tower? If it has
high speed internet, as seems to be the case since the local coffee
shop does have it, you can establish a similar point to point wireless
link, or find a WISP to do it for you.

>the nearest large city is 55 miles.

That's a bit too far.

>I can not get a reliable cell phone signal here.

I live in a hilly area with lots of tall trees. Cellular coverage is
spotty in many places. So, I arrange to have someone install either a
nanocellular base station from the cellular provider, or a yagi
antenna on the roof pointed at the nearest cell site. (I gave up
tower and rooftop climbing about 15 years ago).

>There is no cable.

I've been mildly involved in several neighborhood campaigns to
"convince" the incumbent service provider to provide internet. If
they want a franchise from the city or county, they'll have to provide
service extension for those that are willing to pay for it. For
example:
<http://sccounty01.co.santa-cruz.ca.us/BDS/Govstream2/Bdsvdata/non_legacy_2.0/agendas/2007/20070626-386/PDF/068.pdf>
Get your neighborhood organized and be prepared to make some noises
when your local cable franchise is scheduled for renewal.

>The only way might be a satellite dish.

Only way? You're ignoring almost everything I previously suggested. I
suggest you do some research into wireless internet before declaring
your situation as hopeless. If you're lost, the email address in the
signature works. If you're desperate, so does the phone number. I
just hate to see anyone suffer with only dialup.

>And that would cost me at least $100 per month.

<http://www.exede.com>
$70/month after the teaser rate expires. No TV required. You can
possibly dump your phone service and switch to VoIP or use their phone
offering. You can get a similar prices from:
<https://www.hughesnet.com>
You'll need to buy satellite equipment and have an authorized
installer do the dish installation. Not sure of the prices.

[olds...@tubes.com]

On Sun, 05 Feb 2017 19:18:58 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

>On Sun, 05 Feb 2017 16:47:14 -0600, olds...@tubes.com wrote:
>
>>I am a lot more limited than you could imagine.
>
>Agreed. You've given up before you've even started looking for a
>solution. We have about 5 small and one large wireless ISP's in my
>area that provide reliable service for your situation.
>
>>My nearest neighbor is over a mile away.
>
>Duz this neighbor have high speed internet? If so, a point to point
>wireless link will get you internet.

No, they are Amish. Almost all my neighbors are Amish, except for one
very old retired farmer who I doubt even knows what the internet is.

>
>>The nearest small town is 5 miles,
>
>Can you "see" this small town from your rooftop? From a nearby
>hilltop on your property? From the top of a tree or tower? If it has
>high speed internet, as seems to be the case since the local coffee
>shop does have it, you can establish a similar point to point wireless
>link, or find a WISP to do it for you.
>

I can not see it from my rooftop. There is a woods between my house and
the road. But even without the trees, I could not see the town, unless I
drive to the top of the hill (I live in a valley). My land ends at
almost the top of the hill, and I can probably see the town if I was to
climb a tree, or even stand on top of a full hay wagon full of hay. But
if I go another 50 or 70 feet higher (up the private road), I can easily
see town. (If this is not making sense, my driveway is a shared private
road. Between the county road and my farm, there is cropland. The
driveway is shared by myself and the farmer who owns that land. (He does
not live there, it's just crops). This roadway (driveway) is 2/3 of a
mile from the county road to my house. [and, yea, I have to plow the
whole friggin thing when it snows].

Yes, that town has high speed internet, and has public WIFI at the
library and at a fast food restaurant. As well as a lot of secured WIFI
signals (at businesses) that I can see on my laptop, when I am in town.
I regularly sit in the parking lot at that restaurant and use the WIFI
from my car, even when they are closed.

You lost me, when you started talking about "point to point wireless
link, and WISP".

>>the nearest large city is 55 miles.
>
>That's a bit too far.
>
>>I can not get a reliable cell phone signal here.
>
>I live in a hilly area with lots of tall trees. Cellular coverage is
>spotty in many places. So, I arrange to have someone install either a
>nanocellular base station from the cellular provider, or a yagi
>antenna on the roof pointed at the nearest cell site. (I gave up
>tower and rooftop climbing about 15 years ago).
>

I was looking at those cellphone boosters on ebay. Since I can get a
semi-usable signal on the roof, I thought about putting a yagi antenna
on my tv antenna tower and running that into the house. Part of my
problem is having a house with metal siding and roof.

>>There is no cable.
>
>I've been mildly involved in several neighborhood campaigns to
>"convince" the incumbent service provider to provide internet. If
>they want a franchise from the city or county, they'll have to provide
>service extension for those that are willing to pay for it. For
>example:
><http://sccounty01.co.santa-cruz.ca.us/BDS/Govstream2/Bdsvdata/non_

>egacy_2.0/agendas/2007/20070626-386/PDF/068.pdf>
>Get your neighborhood organized and be prepared to make some noises
>when your local cable franchise is scheduled for renewal.

Getting my Amish neighbors involved is not gonna happen :)

But I did sign a petition to get better cell service, after I raised
hell with some of the law enforcement people in the area. This occurred
about 20 months ago, when I saw a building on fire in another small town
nearby. I had a vehicle breakdown, and I was unable to call anyone for
help, because there is no cell signal at all in that town. So, while I'm
trying to fix my truck in cold weather, I notice a building on fire a
block away, and I cant even call the fire dept. This was during the
night, that town consists of about 100 population and no one drives up
that town's roads during the night. I finally woke someone up by banging
on doors, but by the time they called the fire dept, that building was a
total loss.

After I bitched like hell to the fire dept and other law enforcement,
that petition was created. It was passed around that town and other
nearby small towns. It was at the bars and public buildings, and got
around 250 signatures. The cell company in the area said they were
planning to build a new tower. (But from what I have heard from the
locals, they said that same thing 10 years ago). Nothing has changed.

>
>>The only way might be a satellite dish.
>
>Only way? You're ignoring almost everything I previously suggested. I
>suggest you do some research into wireless internet before declaring
>your situation as hopeless. If you're lost, the email address in the
>signature works. If you're desperate, so does the phone number. I
>just hate to see anyone suffer with only dialup.
>

I hate having to cope with dialup, and worse yet, I can not establish a
decent connection using my US RObotics modem on any computer with
Windows XP. I can only connect using Window 98. I dont mind Win98, in
fact I like it, but the newest browser I can use if Firefox 3.x. At
least half the websites no longer work for me. So I mostly just use
usenet and email most of the time now, but some websites still work. If
they dont load after 10 minutes, I know they will never load.

I may be emailing you soon....

[Jeff Liebermann]

On Mon, 06 Feb 2017 04:21:27 -0600, olds...@tubes.com wrote:

>On Sun, 05 Feb 2017 19:18:58 -0800, Jeff Liebermann <je...@cruzio.com>
>wrote:

>>Duz this neighbor have high speed internet? If so, a point to point
>>wireless link will get you internet.
>
>No, they are Amish. Almost all my neighbors are Amish, except for one
>very old retired farmer who I doubt even knows what the internet is.

The modern equivalent of the Amish are people who claim to be
"electro-sensitive". A former lady friend was like that. I didn't
recognize the similarity until now. Thanks for the hint.

>I can not see it from my rooftop. There is a woods between my house and
>the road. But even without the trees, I could not see the town, unless I
>drive to the top of the hill (I live in a valley). My land ends at
>almost the top of the hill, and I can probably see the town if I was to
>climb a tree, or even stand on top of a full hay wagon full of hay. But
>if I go another 50 or 70 feet higher (up the private road), I can easily
>see town.

I suspect that the aesthetics of a 50ft radio tower would be a show
stopper with the local planning department. However, if you can get
past that, you would end up with a radio tower with one end of a 2.4
or 5GHz wireless bridge with the other end in town with someone who
has high speed internet. Ideally, the backhaul from the tower to your
house would be buried cable or fiber, but can also be wireless. More
commonly, there's a 2nd wireless radio on the tower to distribute
internet to the neighbors, but that doesn't seem to be a requirement
here.

>You lost me, when you started talking about "point to point wireless
>link, and WISP".

WISP is "Wireless Internet Service Provider". It's just like a
conventional cable or telco service providers, but without the wires.
Instead of you building the tower and negotiating for sharing
broadband, the WISP does this for you.

Point to point wireless is basically a wireless bridge. I'll spare
you the details, but here's an example:
<http://www.ebay.com/itm/122182834424>
Think of it as an ethernet network extension cord without wires.

>I was looking at those cellphone boosters on ebay. Since I can get a
>semi-usable signal on the roof, I thought about putting a yagi antenna
>on my tv antenna tower and running that into the house. Part of my
>problem is having a house with metal siding and roof.

The legality of some of those boosters are questionable. They're also
expensive. I have one made by zBoost. Of course, I couldn't resist
tearing it apart and looking inside:
<http://802.11junk.com/jeffl/zBoost/>

>The cell company in the area said they were
>planning to build a new tower. (But from what I have heard from the
>locals, they said that same thing 10 years ago). Nothing has changed.

I had a talk last year with the local Verizon engineer about new site
construction. He casually mentioned that they typically have about
2,000 new sites in progress at any time in Northern California. That
doesn't mean they're building these sites, just at some step in the
process, such as getting approvals from the local councils, boards,
and agencies. If they meet any resistance from citizens groups, that
site goes to the bottom of the list, and they continue working on
those where the locals want a cell site installed. He mentioned that
there were several sites where the locals offered to subsidize the
construction in order to get cellular service. I suspect your
cellular company meet some resistance from the local Amish, and just
walked away.

>I hate having to cope with dialup, and worse yet, I can not establish a
>decent connection using my US RObotics modem on any computer with
>Windows XP.

I used that combination for many years until I was able to get DSL. It
should work. I wrote this during that era to test phone lines using
USR modems:
<http://members.cruzio.com/~jeffl/aty11/aty11.htm>

>I may be emailing you soon....

I was afraid that might happen.

[Chuck]

The 470pf polystyrene capacitors used in the mpx circuits of many
receivers in the 1970s used to fail all the time.

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[Benderthe.evilrobot]

<olds...@tubes.com> wrote in message
news:957f9chh7874ipnge...@4ax.com...

AFAICR: the one with the paper reservoir cap was a regen.

[Benderthe.evilrobot]

"Jim Mueller" <wron...@nospam.com> wrote in message

news:5897ad0a$0$59611$c3e8da3$4605...@news.astraweb.com...

Apparently the tempco of polystyrene is a good match for pot cores.

I've seen polystyrene crack/craze with age - I didn't investigate whether
performance was impaired.

Polystyrene is pretty much the most vulnerable to solvents there is -
fortunately, most de fluxing solvents were banned to protect the ozone
layer.

[Spare Change]

On Feb 2, 2017, olds...@tubes.com wrote
(in article<32779ctsu0qa604ak...@4ax.com>):

> Why should someone replace ALL the capacitors on old Tube equipment?

<https://en.wikipedia.org/wiki/Glowing_plate#Common_Occurrences>

Several causes listed are caused by shorted or leaking capacitors. It’s a
tube killer.

[cl...@snyder.on.ca]

A;so the sinle largest killer of hard to replace power transformers.

[Benderthe.evilrobot]

<cl...@snyder.on.ca> wrote in message
news:th7k9cl63nqp5gaql...@4ax.com...

Not to mention a leaky grid coupling cap can pass a large DC voltage from
the plate of the previous stage. I've seen tubes that got so hot the glass
melted and the vacuum wrapped it round the internal structure like cling
film.

If it happens in Ham gear - the PA tubes are seriously expensive.

[olds...@tubes.com]

I have put fuses on the secondaries of the power transformer on some
high powered amplifiers. (On the high voltage leads). That protects the
xformer as well as other parts. Line fuses on the primary are not enough
in my opinion.

[Michael Black]

There are stories of Collins receivers, I forget which model, where the
capacitor feeding the mechanical filter can go bad, and the result is
a ruined mechanical filter, it can't handle the DC going through it.

SO that's the sort of thing knowledge that is out there for people coming
to an old receiver for the first time.

Michael

[olds...@tubes.com]

On Tue, 7 Feb 2017 16:11:28 -0500, Michael Black <et...@ncf.ca> wrote:

>There are stories of Collins receivers, I forget which model, where the
>capacitor feeding the mechanical filter can go bad, and the result is
>a ruined mechanical filter, it can't handle the DC going through it.
>
>SO that's the sort of thing knowledge that is out there for people coming
>to an old receiver for the first time.
>
> Michael

What is a " mechanical filter"?

[Benderthe.evilrobot]

<olds...@tubes.com> wrote in message
news:im3n9c5c1ogspq5fk...@4ax.com...

Pretty much what the name says it is.

Usually a row of disks with a mechanical resonant frequency, AFAIK: the
transducers at each end were usually inductive, but I believe there were
piezo types.

At one time they were the most common type of IF selectivity in Ham radio
and other communications gear.

[Michael Black]

It provide selectivity in the receiver. It goes in the IF, at 455KHz or
sometimes 500KHz or even I have one at 250KHz. Generally for narrow
selctivity, like for SSB or CW. Kind of expensive, but even more so
decades later when they are no longer being made, and finding a specific
model may not be so easy. So if the capacitor goes, it can be expensive
to remedy.

Michael

[Foxs Mercantile]

On 2/8/2017 3:34 PM, olds...@tubes.com wrote:
>
> What is a " mechanical filter"?

<http://www.wa3key.com/filters.html>

[Michael Black]

I think that's debateable.

For a long time IF transformers were "good enough" and a single crystal
filter was the step up. Those were common until the SSB age in the
mid-fifties, when mechanical filters became somewhat common, but
multi-crystal filters also came along at that point, and within a few
years the shift was to a crystal filter in the HF range.

Collins used mechanical filters in their receivers, but not all of them.
Some CB sets used them, helped in part because some company in Japan made
a cheaper mechanical filter, but that wsa sort of a blip, ceramic filters
ame along soon after and they were cheaper. Upper end equipment tended to
use mechanical filters right to the end, when Collins stopped making them
a few years ago, the implied move to software radios taking over.

Some ham SSB sets used them, and I had an RCA SSB Carphone that had a
250KHz mechanical filter.

But lots of other equipment used other things rather than mechanical
filters.

Michael

[Foxs Mercantile]

On 2/9/2017 2:08 PM, Michael Black wrote:
> Collins used mechanical filters in their receivers, but not all
> of them.

Collins introduced them in the 75A-4 and 51J-4 receivers back in
the early '50s.

Drake used a 50 KHz IF and tuned LC filters in their receivers up
until the mid '60s.

The alternative to Collins mechanical filters were multi-pole crystal
filters. Which was what everyone else was using.

One of the stranger things to come across was Henry Radio offered a
kit to install a Collins mechanical filter in the Drake 2B receiver.

Absolutely pointless, but it allowed you to win "dick waving" contests.

[jurb...@gmail.com]

>"I would like to find out what problems are specific to the Hallicrafters
SX-99. Where is a good place to look? "

Inside the Hallicrafters SX-99 would be my first guess.

>"
I'd be interested in which of the old caps were known to have "issues".
or to fail. Sure, they are all old (in any tube equipmnent), and they
are paper caps, which are no longer made, but I'm sure some brands were
better or worse than others. "

The bad caps in old tube radios have already lasted longer than any normal engineer would plan for. The people who made those caps, by default, made them to last forever. so much for that. Of course as you know some of them can be reformed. Not that I would trust that in a heart/lung machine, but maybe for a table radio.

>"(snipped the BS about older caps) Paper caps
seem to have passed the test of time. We wont know if these newer
materials pass the test of time or not, until we get there. "

We do know, and they don't. Newer capacitors have failure modes that'll put hair on your chest, curl it and take it off in one fell swoop.

I worked on bigscreen TVs, which were a fad here in the US and I made alot of money off of it because nobody else could understand it.

Well there were YEARS of Mitsubishi product out there with defective caps. someone (Rubycon ?) stole a formula for the electrolyte which was not yet perfected. but they made the caps and they had higher density, which means capacitance and voltage ratings in a smaller size. Thatis what determines the value of an electrolytic capacitor on the market. You got ESR, ESL, intolerance to heat as minus, microfarads and voltage are the plus. And the smaller the better.

You have to think outside the box to really understand this, electrolytes are not necessarily insulators. In fact when they leaked out on the board of $3,500 Mitsubishi TVs they caused leakage paths on the PC board.

Forget air and vacuum as an electrolyte, they are actually not. The electrolyte is more like the acid in your car battery.

Anyway, I have done alot of service and streamlined many the process. If you look at the damn schematic you can tell which caps are stressed worse and you know to replace them. New caps have hours before MTF based on ripple current. Well some do. Elcheapo ones do not give specs because they are so dismal, like the THD rating of a loudspeaker, they could never sell amps with 0.03 % distortion if people knew that actually good speakers usually have 5 % or more at normal listening levels. Of course some are lower, go have a look at the Martin Logan website for that, and if that doesn't make your wallet hurt go find some Quad ESL-63s.

In other words some things matter, others do not. Like I am about to work on a Pioneer SX-737. I am NOT replacing all the caps, and BTW, those big ones in the power supply, when they are bulging they are not necessarily bad. I am replacoing a bunch of PNP transistors because they were prone to failure ad could damage other components. there are a few caps I am going to change and I will (upon request) supply the schematic and my professional judgement as to why these caps get changed and why the others do not. If you understand the circuit you realize that some of these caps are nowhere near the audio path and do not affect the sound. If they pose a reliability problem that is different.

Now, you brought up old caps, and upon that I would like to expound a bit. A couple few years ago my sister's PC monitor crapped out. I had already been working on flatscrteen TVs so I knew the deal. I found a bank of caps, which is usually what they are, all bad. See, in business toward the end I did not replace all kinds of caps, I just bridged one in and when it worked I knew the caps would fix it. this was my job.

But this was far from professional. Her power supply of course worked up in the hundreds of KHz. I had no caps at the house but a thirty years old one. Originally in the circuit there was a bank of 1,000 uF @ I think 35 volts, I only had 25s.

I took and old 100 uF @ 160 volts and stuck it in there and it worked. Think about it, a good cap, 100 KHz ? /Of course it worked.

I told her I really did not have the right part right now so be ready for it to fail, and I will order the right part.

It has been running for over three years now.

These engineers are idiots, they use banks of caps of poor quality instead of just a few good ones. But then they need to design next year's product you are forced to buy because this one failed. Like the government, is it complicity or incompetence ? To me it does not matter, they need for some heads to roll. They are wrecking the fucking planet.

Guy on here talking about Taiwan or whatever dog country saying it is a dumping ground for our junk electronics. GOOD ! That is where the garbage came from in the first place ! Take it back. In fact take it all back. I want to go back to where I have only six channels on the TV. I shit you not.

And I want a table radio in the kitchen.

Know what ? Off to eBay, or better yet Craigslist.