Consumer electronics "war stories"

[Mark Zacharias]

OK, so it appears there is very little to discuss on this group in areas
like repairing audio components, amps, receivers, power supplies, etc these
days.

I "tune in" here almost daily and rarely find anything of interest to me.

Maybe we could share some "war stories" of cool repairs we have done in the
past.

Re-live some past glories?

The first time you traced down a bad reset line for a microprocessor?

That integrated amp that blew a channel about once a year until you caught
that bias diode occasionally opening up?

Sansui 5000A's? (yuck)

Crappy Euro caps in Tandberg tape decks?

Those times you sweated whether you could even get this thing put back
together?

Any more recent successs stories to brag about?

C'mon, don't we all enjoy patting ourselves on the back, really?


Mark Z.

[N_Cook]

My favourite was the car audio cassette player, ie no record function.
It recorded vinyl record clicks on to any prerecorded tape played in there.
Answer at end of spoiler defeat, run of +








+













+










+













+



























The pinch wheel had a tiny piece of magnet fragment embedded in it

[Cydrome Leader]

Mark Zacharias <mark_za...@sbcglobal.net> wrote:
> OK, so it appears there is very little to discuss on this group in areas
> like repairing audio components, amps, receivers, power supplies, etc these
> days.
>
> I "tune in" here almost daily and rarely find anything of interest to me.
>
> Maybe we could share some "war stories" of cool repairs we have done in the
> past.
>
> Re-live some past glories?
>
> The first time you traced down a bad reset line for a microprocessor?

My first computer was a Franklin Ace 1000 that was give to me broken. It
had complete schematics so I was able to trace out what was in fact a bad
reset signal going to the CPU. Pretty sure it was a 74S161 (something that
ran hot and wasn't LS series) that had to be swapped out and it was fine
again. Donor chip came from an arcade machine board. Looking that part up
I see it's a 4 bit counter- if that's correct it may have someting to do
with the video timing signals which were a weird hack in the Apple ][
which this machine was an improved clone of.

[Trevor Wilson]

**I recall the first time (1980-ish) I discovered those fusible
resistors that go high after a few years. With no obvious signs of
distress. Now I just head straight for the buggers.

Then there's those low value (</=47 Ohms), 1/4W cracked carbon resistors
that go O/C when subjected to ca. 60+ Volts with no signs of burning
(Marantz 1200b, 240, 250M, 500 models). Over the years, I learned to
suspect any resistor over the value of 100k, if the circuit is
displaying some kind of mysterious fault that cannot be explained by a
semiconductor failure or cap leakage.

--
Trevor Wilson
www.rageaudio.com.au

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

[et...@whidbey.com]

That resistor story is interesting. About two years ago I had a linear
power supply fail in one of my CNC machines. I did the troubleshooting
bit and discovered a bad -15 volt regulator. So I replaced it and then
a few weeks later something else went bad and I couldn't find it. I
took it to a friend who is an electronics engineer and he discovered
an open resistor. I asked why he checked it because there was no
visual reason for it to be bad. It wasn't cracked or discolored. He
said that's what he usually did first, check for open resistors. He
said it was a common fault. Since then the power supply has been
operating fine.
Eric

[Mark Zacharias]

<et...@whidbey.com> wrote in message
news:e5l16bt7rbnma2osr...@4ax.com...

Yeah - when "the usual suspects" don't pan out, I start looking for bad high
value resistors.

Had a bad 150K 1/8 watt carbon on a late model Pioneer surround receiver the
other day.


Mark Z.

[amdx]

On 12/3/2015 6:34 AM, Mark Zacharias wrote:

>
> C'mon, don't we all enjoy patting ourselves on the back, really?
>
>
> Mark Z.

I posted this an hour ago, but it hasn't shown up, so I'll do it again.

Back 30 years ago I stopped at a consumer electronics/TV repair shop
and presented my resume. I had been to many manufacturer service
training seminars and had a hand full of certificates of completion. The
owner looked it over and said, "I just hired a guy, I wish you came in
earlier." So I went home and about 45 minutes later he called and said,
"I see you have a lot of Sony training, I have this projection TV in
here that nobody can fix, I'd be happy to pay you for looking at it."
So I drove down and got the manual, noted the problem was, no output
from the 3 tubes. I started poking around in the HV section, and within
minutes the owner said, hey you got it working! I didn't know it was
working ;-} I put my head out front and it had an output.
Hmm, I unhooked my scope probe and the picture went with it.
From there, we, more he, figured out one of the other techs replaced a
cap with 1/10 the proper value, the scope probe hanging on the test
point had enough capacitance to make the set work.
He hired me that day, it was good, within two blocks of my house.
So, I got a job by accident.
Mikek

[mako...@yahoo.com]

One of my favorite stories is from electronics lab in college.

We had to build a small two stage transistor audio amp in the lab with parts from the stock room, onto a protoboard like breadboard.

My lab partners and I were experienced hams and got ours working in no time , no problems.

The PHD proffesor called me over to help him troubleshoot another groups that they could not get to work.

The design had a 10uf cap between the two stages.

I looked at the other groups breadboard and immediatly saw a tiny ceramic cap with a 10 printed on it between the two stages.

I pointed to the cap and said, that doesn't look right.

Got an A in that lab.

=========================

Oh another one.

I worked for a company that made CATV settop boxes.
I wandered into the lab where a group of young engineers were stuck troubleshooting a new box design. The picture was black and white and they could not figure out why there was no color. Looking into the box I saw a crystal marked 3.579545.

On a total whim, I put my fingers on the crystal.

The picture immediatly snapped into color!!!!

I was amazed myself but didn't let it show....I just cooly said, there is your problem and walked away. :-)



And lastly, in the same vein
you will all enjoy this story

http://www.rfcafe.com/references/popular-electronics/me-technician-you-engineer-february-1963-popular-electronics.htm

Have fun

Mark







Mark...
====================

[sound....@btconnect.com]

My favourite - I was working for a Pro PA hire compoany in London. They had supplied a monitor system for a BBC recording of Public Image Ltd at Maida Vale Studios, London. The system was buzzing like crazy and none of the Sound Company or BBC engineers could work out why. They were about to pull the whole gig.
They sent me down as a last faint hope.

It was obviously some kind of mains problem, but everything seemed to check out fine on multimeters. Earths, Neutrals were all at 0v.
Eventually I decided to plug in my scope, to discover that instead of a nice straight line accross the display, it was massively modulated.
Clearly the scope's Earth wasn't a proper Earth but had some mains on it.
I then was able to track down the fault - one multi-way extension cable attatched to the many, many pieces of equipment had Earth and Neutral reversed, thus connecting all Earths and Neutrals in the middle of the studio as well as back at the mains Intake.

Ripped the offending extension out, the buzzing ceased immediately, and the BBC and Public Image Limited got their recording and the Sound Company didn't lose the gig or it's reputation.



Gareth.

[Chuck]

The receiver tech was flummoxed by one of those large 1970s Pioneer
receivers. It had a problem none of us had seen before and we were a
high volume audio chain. There was slight audio distortion on both
channels, only on FM. We all worked commission only so I was the only
one to volunteer to help him out. To cut to the chase, the receiver
had an over designed mute circuit that was 3 or 4 stages deep, At the
deepest stage there was one of the Sanyo electrolytics that became a
common failure item many years later which was slightly leaky.

I've got another one. In the early 80s there were these 19" Hitachi
tvs that ghosted. It looked exactly like a bad delay line. By that
time I ran the TV service department for the same company. We had
just switched over to the big box store concept and I was inundated
with broken tvs. Out of desperation, I switched out the CRT and the
ghosting disappeared. We sold 1000s of these sets and I saw the
problem 3 more times.

And another. Kenwood sold these Funai made cd changers that never
worked properly. All of them would come back with skipping or not
playing discs problems. Kenwood came out with 3 or 4 mods, none which
worked. Sometimes they would work for months before they came back.
Somehow I found out if the mechanism retaining springs were stretched
so the mechanism didn't sag at all, the problem disappeared. Called
up Kenwood and they put out a mod kit that included strong springs
which also didn't allow any downward movement of the mechanism.

Last one. There were these very expensive ADS cd players which would
play any disc except a ,very popular at the time, Jimi Hendrix Ryko
disc. Couldn't find any electronic or mechanical problems. I slightly
moved the CD turntable slightly down on the spindle and this disc and
all other discs would play.

[John-Del]

The one pops to mind took couple of years off my life. It was an old Hitachi built RCA projection TV (circa 1981) that had blown fuses in the power supply, but nothing showed a short resistance wise. I replaced the fuses and it powered up, only the geometry didn't look right. When I went to connect the cable back on to it to see exactly what the picture was like a blinding flash and arc appeared at the RF connector and it blew the fuses again. Working pretty much on my stomach in a cramped house, I traced a hot side/cold side short all the way back to the end of the line, which was a leaky deflection yoke (vert winding to horiz winding). It seems the horiz winding was on the hot side of the chassis and the vert winding was on the cold side. How it didn't blow the vert IC or horiz deflection output is a mystery.

[Ralph Mowery]

"Chuck" <c...@dejanews.net> wrote in message
news:vrj36blm2d6ad0cti...@4ax.com...

>> The receiver tech was flummoxed by one of those large 1970s Pioneer
> receivers. It had a problem none of us had seen before and we were a
> high volume audio chain. There was slight audio distortion on both
> channels, only on FM. We all worked commission only so I was the only
> one to volunteer to help him out. To cut to the chase, the receiver
> had an over designed mute circuit that was 3 or 4 stages deep, At the
> deepest stage there was one of the Sanyo electrolytics that became a
> common failure item many years later which was slightly leaky.
>

Many electronic devices will have a common problem. It may take a while to
find it,but once found, the first thing to look for.

I worked for a large company and we had a new building built and equipment
installed. All was fine for a while, the some heaters for the process got
where they would not come on if cut off. I was the first one to get a call
about this. Took about 2 or 3 hours to troubleshoot this as it was the
first time anyone had worked on it. Found a bad plug in time delay relay
was bad. After that a simple one point voltage check would usually tell the
relay was bad. Next time it only took seconds to change out the relay and
was usually done any time they would not come on. 99.9% of the time that
was the problem. As that place operated 24 hours a day, the peopel in
production was told about it and told the electrician that showed up to
change it out if they did not know what the problem might be. Saved lots of
late night phone calls.

[amdx]

On 12/3/2015 6:34 AM, Mark Zacharias wrote:

In the late 80s early 90's I worked on VCR's. The Fisher FVH 906,
had a tuner that went defective, no schematic, a replacement part only.
That's ok under warranty, but after that, the part cost was to high to
get a repair ok. So one day, I decided to see if I could find out what
the cause of the failure was. I started spraying parts with freeze mist
and found when I hit a 1uf 35V cap the picture came back. I made a lot
of repairs, replacing that same cap on a whole bunch of tuners.
I'd do the same thing every time, dribble 2 or 3 drops of freeze mist
on the cap and the picture came in.

I had a customer bring in a remote for repair, it checked out fine.
He took it home and called saying it didn't work. I talked to him a bit
and found he had just install new CFL lights. I suggested he shield that
light and try it. It worked, I had just read about that in a trade
magazine two days previous.
Mikek

I got in early on the VCR curve, they were expensive, commanding high
service rates, then when prices dropped we had a high volume of repairs,
rode it down until the price was close to $200, then I moved to Florida.
A year later the tech that took my place said he came in a couple days
a week to repair the few that came in. I repaired a little over 11,000
vcr's in ten years, it was a good time.

[Phil Allison]

sound....@btconnect.com wrote:
>
>
> I then was able to track down the fault - one multi-way extension
> cable attatched to the many, many pieces of equipment had Earth
> and Neutral reversed, thus connecting all Earths and Neutrals
> in the middle of the studio as well as back at the mains Intake.
>
> Ripped the offending extension out, the buzzing ceased immediately,
> and the BBC and Public Image Limited got their recording and the
> Sound Company didn't lose the gig or it's reputation.
>
>

** I know of a similar example involving a 30kW, 3 phase lighting system for live entertainment here in Sydney. Was back when lighting consoles communicated
with triac dimmer racks via 0-10V analogue signals.

The system seemed to have a mind of its own, lights came up and varied about with all faders set to zero. Bringing one fader up affected many others.

After hours of fruitless searching, the culprit was identified as the AC plug on the lighting console itself which had neutral & earth reversed.

Seems a roadie had fitted a new plug after accidentally damaging the original and told nobody.


.... Phil

[Dave M]

One of my first chances to stick my chest out and strut was shortly after I
checked aboard my first duty ship during my stint in the Navy in mid-1964.
Barely 20 years old, I was assigned to overhaul & repair of UHF shipboard
radio transmitters.

The ship had a small calibration lab, which was staffed by a PO1, a PO2s and
a couple PO3s (POs are Petty Officers... enlisted men) who had all been to
the elite Air Force PMEL calibration school in Colorado. One day, after all
the cal lab techs had a shot at it and several of the other bench techs had
also been called in to try fixing it,, I was called in to take a shot at
repairing a new HP 524D 10MC digital counter from another ship. It just
wouldn't show any indication of trying to count... all the displays just
sat at zero no matter what the input signal looked like.

I sat down and took a look at the schematic, hooked a scope probe to the
output of the gate tube, a 6AL5. No pulses. Hooked the probe to the gate
input to the gate tube. Good gate pulses. Hooked the probe to the signal
input of the gate tube. Good squared pulses that followed the frequency of
the input signal.
I asked for a 6AL5 tube, plugged it in, and Voila! everything came to life.

Made me feel kinda good that it only took me about 10 minutes to fix what
had stumped 9 or 10 good techs for several days. From that day until now, I
have had an affinity for test instruments, especially those used for time &
frequency measurement.

Dave M

[Phil Allison]

Mark Zacharias wrote:
>
>
> OK, so it appears there is very little to discuss on this group in areas
> like repairing audio components, amps, receivers, power supplies, etc these
> days.
>
> I "tune in" here almost daily and rarely find anything of interest to me.
>
> Maybe we could share some "war stories" of cool repairs we have done in the
> past.
>
> Re-live some past glories?
>

** Ok, here is a wacky one:

I once had a customer who rented out DJ systems: turntable & mixer consoles, stereo amps and speakers. DJs back then owned a collection of LPs and generally rented audio gear on a daily basis.

So I got this TT console with the complaint while it started off OK, it was losing volume & changing tone after a while becoming duller and duller until full treble was needed to correct it.

The story sounded dubious, but I checked out the mixer thoroughly using hot air and an all day soak test - result negative, it worked fine all the time.

Handed it back to the hire business guy and a week later it was returned with the SAME complaint plus some hostility that I had clearly not fixed it. Naturally it passed all tests again.

I had a chat with the hire guy and he agreed to use the console himself at a gig and of course it worked fine all night. Next time it went out on hire, he got the same complaint from the same DJ - who was by now ropable that nothing had been done about the problem.

So my hire guy paid a visit to the venue where the gear was being used, his first. When he walked in, he was nearly deafened by the volume and the sound was absurdly shrill. On approaching the DJ and noticing that volume and treble controls were all maxed out - he was told:

" See what I mean ??

Sounds piss weak and there's no treble."



.... Phil

[jurb...@gmail.com]

Chances are he'll never hear his grandkids cry.

[c4urs11]

On Thu, 03 Dec 2015 06:34:55 -0600, Mark Zacharias wrote:

> Maybe we could share some "war stories" of cool repairs we have done
> in the past.

Somewhere in the eighties we installed a custom-built control system in
a 24/7 assembly line for SIL ceramic hybrid circuits.
Subcontractor of subcontractor job.

One night I was called in for an unexpected stop.
Inside the plant I was 'greeted' by the crowd of tech support people and
blaming managers gathered around our equipment.
On my way to the control system I came across one of the typical mushroom
emergency stops along the production line.
By habit I twisted the knob and felt the release spring.
I worked my way to the control panel and engaged the start.
Within seconds the crowd silenced and fled the scene: the line was up.

We were never again called in.

[Mark Zacharias]

"c4urs11" <c4u...@domain.hidden> wrote in message
news:14493106...@news.evonet.be...

About 1981 I was still in tech school and not even really a technician yet.

(I was SO green).

Third semester, servicing phase. There was an old GE tube chassis color set
with intermittent color sync. It was a "re-do" which the prior class had
failed to fix correctly.

I got to the burst gate amp and saw there was a much smaller signal at the
grid than called for.

Also, there was a neon lamp in the grid circuit which was supposed to drop
75 or so volts and the drop was much higher than expected, plus the lamp
glowed somewhat faintly at it's base instead of lighting fully.

I couldn't get the instructor to order a miserable 75 cent neon lamp. He
kept me running around checking this cap or this resistor, etc.

Finally I went around him to another instructor, explained my logic and got
the lamp ordered.

Fixed the tv. My instructor never really forgave me for that.


Mark Z.

[Mark Zacharias]

Things that are second nature to us now were "learning experiences" back
then, yes?

At my first job as a tech, about the second piece I ever worked on was a
Pioneer SX-828.

Yup - the infamous "blue Sanyo cap" scenario.

Except I had never heard of that and had no tech support or even a more
experienced tech along side me.

I was totally on my own, as I usually was during the first 15 or 20 years of
my career.

Symptom: one channel gone, just a low hiss. Preamp issue.

Tracing signal - got it, don't got it, and so on.

In the tone amp, DC voltage low at collector of one transistor.

1.5uF Sanyo coupling cap to base was leaky, driving that stage into
saturation.

Felt really good about that one.


Mark Z.

[mog...@hotmail.com]

On Friday, December 4, 2015 at 1:53:47 PM UTC-5, Ralph Mowery wrote:
> "Chuck" <c...@dejanews.net> wrote in in sci.electronics.repair in message

> news:vrj36blm2d6ad0cti...@4ax.com...
> >> The receiver tech was flummoxed by one of those large 1970s Pioneer
> > receivers. It had a problem none of us had seen before and we were a
> > high volume audio chain. There was slight audio distortion on both
> > channels, only on FM. We all worked commission only so I was the only
> > one to volunteer to help him out. To cut to the chase, the receiver
> > had an over designed mute circuit that was 3 or 4 stages deep, At the
> > deepest stage there was one of the Sanyo electrolytics that became a
> > common failure item many years later which was slightly leaky.
>
> Many electronic devices will have a common problem. It may take a while to
> find it,but once found, the first thing to look for.

Most of them have microchips (that you can't open up and repair). And they have software and wireless or hard wired connections to larger facilities elsewhere where techs can come in and review the software.

Many problems seem to be caused from malware or spyware (maybe some even from the government or other places) that intentionally interferes with the intended software provided by the company on the package's label.

> I worked for a large company and we had a new building built and
> equipment installed.

Right now, I'm not even working. I'm just sitting around looking at space cartoons and video games.

[amdx]

I had an SX-828, bought it sometime in the early 70s.
Been so many years, I don't recall the problem, but
I tossed it about two years ago, just too much stuff.

Mikek

[Mark Zacharias]

Here's one.

Onkyo cassette deck, circa 1986. Perhaps a TA-630 or some such.

Played just fine in PLAY mode.

In REC mode only, the auto-stop would trigger at random times.

Partially open bridge rectifier. One of those little black round ones. In
PLAY mode the voltages held up, but in REC mode the additional load of the
bias oscillator dropped the voltage enough to cause the problem.

Ripple waveform was definitive. Showed 1/2 wave pattern where it should have
been full-wave.


Mark Z.

[Chuck]

These bridge rectifiers also caused weird problems in Onkyo receivers
of the 1980s.

[mog...@hotmail.com]

On Saturday, December 5, 2015 at 2:44:26 PM UTC-5, Jon Elson wrote in rec.crafts.metalworking:
> OK, we got one of those fancy energy-saving washing machines. After a few
> years, it started having trouble filling with water. I replaced the
> solenoid valve assembly twice over about 6 months, and then started
> invetigating deeper. The control board had a micro and about a dozen
> electeromechanical relays on it. The one for the cold water valve
> eventually developed contacts burned so bad that I was able to diagnose it.
> I replaced it with a solid state relay, and all has been good for several
> years. I gues the cold water valve gets cycled the most often, so that
> relay got burned up first. No problem yet with any of the others.

Yeah, obviously a current relay or just that kind of an interface or something. Tell 'em about it, so they can buy you a whole new one.

You can't get anything if you stay silent. (I learned that the hard way)

[Chuck]

For a very short time in the 1980s, Kenwood manufactured amplifiers
with wrong value resistors at various locations. The first one was a
bear because I had never seen a Japanese company make that kind of
mistake.

[Chuck]

In a similar vein to your remote story, we sold an $1800 Tandberg
cassette deck that came to the shop over and over again for not
responding to the transport keys. In the shop it always worked
perfectly. I decided to go to the customer's house after work to see
what the problem was. At his house, the keys didn't work. I spotted
a light dimmer on the wall. Turning it off and the deck worked
perfectly.

[Jeff Liebermann]

On Thu, 3 Dec 2015 06:34:55 -0600, "Mark Zacharias"
<mark_za...@sbcglobal.net> wrote:

>Any more recent successs stories to brag about?
>C'mon, don't we all enjoy patting ourselves on the back, really?
>Mark Z.

I haven't bothered to write anything new, but in 1994, I scribbled
this list for Wired Magazine, which never bothered to print it or pay
me:
<http://members.cruzio.com/~jeffl/nooze/support.txt>
I'm not sure I could call these success stories, but since I got paid
for most of the repairs, I guess it qualifies as successful.


--
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

[M Philbrook]

In article <14493106...@news.evonet.be>, c4u...@domain.hidden
says...

And what was the charge for that?

$1 for resetting the switch and $9,999.00 for knowing which one?

Jamie

[M Philbrook]

In article <nsl66bdu96kpnnu4l...@4ax.com>, c...@dejanews.net
says...

>
> In a similar vein to your remote story, we sold an $1800 Tandberg
> cassette deck that came to the shop over and over again for not
> responding to the transport keys. In the shop it always worked
> perfectly. I decided to go to the customer's house after work to see
> what the problem was. At his house, the keys didn't work. I spotted
> a light dimmer on the wall. Turning it off and the deck worked
> perfectly.
>
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
>
>

While I was in a neighborhood visiting a nice looking girl, a friend of
hers ask if I could go over to their place and see why their portable
color TV near the door had messed up colors they could not remove.

I really didn't want to go and told them it would be a minimum of $20
bucks just to walk in, they accepted.

So I walked in and didn't even bother to turn the TV on. I reached up
on top of the TV set and removed the 9x6 Triaxal Speaker with a large
magnet on it, sitting there for what ever reason, I have no idea why.

I held my hand out for the money! They asked aren't you going to even
turn it on? I said, you can do that, they did and could not believe what
they saw. I took the money and said, have a good day now..

Jamie

[Phil Allison]

Chuck wrote:

>
>
> In a similar vein to your remote story, we sold an $1800 Tandberg
> cassette deck that came to the shop over and over again for not
> responding to the transport keys. In the shop it always worked
> perfectly. I decided to go to the customer's house after work to see
> what the problem was. At his house, the keys didn't work. I spotted
> a light dimmer on the wall. Turning it off and the deck worked
> perfectly.

** Need more explanation for that one.


.... Phil

[Bruce Esquibel]

amdx <noj...@knology.net> wrote:

> I had an SX-828, bought it sometime in the early 70s.
> Been so many years, I don't recall the problem, but
> I tossed it about two years ago, just too much stuff.

Heh, anyone else reading this, before you toss it, check ebay for the
completed listings on both working and non-working audio stuff from the
70's and 80's, it's nuts.

Even if that 828 was broke, it seems to fetch $100-$150 and the working ones
$200 on up.

Some of the top of the line ones from back then (pio sx-1980, sansui 5500 i
think) in the thousands. This isn't the old tube stuff like Fisher and
Marantz, just the popular solid state crap from the 70's and 80's.

The power amps and speakers don't follow but anything with receivers and
turntables from that period, you probably can make back what you paid for it
new, and then some.

-bruce
b...@ripco.com

[jurb...@gmail.com]

You can get them cheaper if you get lucky. Some of those three day auctions on eBay n shit. But there is quite a number of people who appreciate that old stuff. Like me, I see no reason my amplifier needs wifi. I knew we were going downhill when I saw an amp with an RJ-45. And to me, this new stuff mostly sounds like shit.

And I don't like the idea of 12 balsa wood speakers the quality of a 1966 table radio and one woofer. Stereo was invented because we got two ears. I might even tolerate quad, but 7.1 ? Nope. I have a hard enough time understanding the words in stereo and on TV I usually switch it to mono.

Anyway, the prices of some of this stuff are outrageous. A Marantz like my old one, $700. Look up the price of a Marantz 2385. A Pioneer SX-1980. (not sure but I think that was the most powerful receiver ever built) Recently a turntable went for $55,000. What's more I talked to my buddy and mentioned that and he told me they go higher, up into six figures.

And now, down in Sydney, Australia, Elton John was spotted in a record store buying albums. The guy can afford anything he wants but he wants a record player. (and logically, records of course)

There is quite the renewed interest in vinyl these days. Even youngins. Guys on AK for example talking about how they just got their teenager a turntable and an old vintage system. Sometimes for their college dorm if that is where they live, other times wherever.

In fact right now we are setting up something of a lab for this stuff. Distortion tester, standards to calibrate everything for power output measurements, and more to come. The idea here is to be sure the stuff is working right because when it is 40 years old it can have insidious problems that only distort a little and won't be noticed right away. And when you get them running really right, that old 1970s shit blows most of the new shit away.

Don't get me wrong, there is a high end still but if you think about 1979 dollars and a receiver is $400, how much would that be today ? Well, it IS. The same relative level of quality easily costs four times the money. What you get for $400 is like what you got for $79 back then, although THAT quality is a bit better.

Just not that much. Not enough for me.

I don't use it, but I got a Pioneer SX-850. No lid, no bottom, glass in front broke, tuning shaft bent. Power suppl.y board was broke in three places, needed work on that, one channel of the power amp and the preamp as well ! It works. It is a rag. It is filthy but everything works.

Not for sale.

[jurb...@gmail.com]

Well I guess it is my turn.

NAP bigscreen no sound - vertical control IC.

Everything runs off the data and clock lines. This IC does the "S" correction and things like that pertaining to linearity. It is of course bus addressed. The one line, data or clock, doesn't matter, was clamping the signal down to like 2 volts. Leaky. That meant the data from the EPROM was not read when the unit got initialized so it did not know which sound system it had and never upped that.

Sony 32" loses green and blue - adjust vertical height.

This was an interesting comedy of failure mode. Apparently when they came out with AKB a had to be done to the CRT aperture grill frame. It reflected too much. The CRT had just been replaced. The way I figure it they used a dud from a non-AKB set. When the pulses feeding the cathodes to detect the current got to the frame they reflected like all hell and told the circuit there was too much green, and then blue as the circuit drifted a bit and brought the lines over the metal. I found this out with the scope. I mean, there is no green but it is getting alot of green feedback. WTF !

And THEN, to adjust the vertical you use a service menu. Guess what color the numbers and letters are in that menu. They were not red but if you left the set on for a while all you had was red.

I got some good ones about cars too.

[Chuck]

The light dimmer was putting an enormous amount of hash on the mains;
somehow it was getting into the microprocessor circuitry. I had seen
this before on much cheaper items so I had a hunch that this was the
problem.

[jurb...@gmail.com]

I almost want to say it was a fault, but it may have been the design. Really, when you talk old stuff, some things just did not exist back then. Things that cause more interference.

When working on older equipment, much older, I had to learn not to expect too much.

In that case with the Tandberg I would have gotten some line filtering. they make those all put together units you can put right at the AC input, light enough so you can cut the cord even and just glue them about anywhere, just make sure they are as close to the AC inlet as possible.

To figure it all out we woukld need the print for that Tandberg. I remember working on one R2R deck that had no microprocessor. It was all gates and comparators and all that. I think it was a 9200 ??? So that one probably would have been alright, no keyboard scanning or any of that, just a bunch of switches and flipflops and gates. and then the solenoid and relay drivers, oh and the current drivers for the eddy current motors.

Simple, I liked it. I fixed it. It got sold. It got damaged in shipping. We got fucked. I wish I would have kept it but really, I have no tapes.

[Phil Allison]

Chuck wrote:

>
>
>
> The light dimmer was putting an enormous amount of hash on the mains;
> somehow it was getting into the microprocessor circuitry. I had seen
> this before on much cheaper items so I had a hunch that this was the
> problem.
>
>

** Wall dimmers put large voltage spikes on the wiring going to the lamp/s concerned - two spikes per cycle at up to the peak AC voltage. This radiates as buzzing noise across the audio and also AM radio bands.

Well shielded, low impedance gear is not affected but anything high impedance and not well shielded picks it up. Electric guitars and some keyboards are particularly susceptible.

Seems your Tandberg was too and that is piss poor design.


.... Phil

[Mike Tomlinson]

En el artículo <vtm66b5hsssqq9u6s...@4ax.com>, Jeff
Liebermann <je...@cruzio.com> escribió:

><http://members.cruzio.com/~jeffl/nooze/support.txt>

Good fun. Thanks for posting that.

Number 10 reminded me of this:

https://en.wikipedia.org/wiki/Lp0_on_fire

My first-ever call out to a Unix system was to this very message.

--
(\_/)
(='.'=) Bunny says: Windows 10? Nein danke!
(")_(")

[whit3rd]

On Sunday, December 6, 2015 at 5:24:04 PM UTC-8, Phil Allison wrote:

> > The light dimmer was putting an enormous amount of hash on the mains;
> > somehow it was getting into the microprocessor circuitry.

> ** Wall dimmers put large voltage spikes on the wiring...

> Well shielded, low impedance gear is not affected but anything high impedance and not well shielded picks it up.

There's another possibility: knob/tube wiring puts those spikes on distant
HOT and NEUTRAL wires (not a close-spaced pair). So, there can be significant
magnetic induction, and that can mess up low impedance circuitry. It used
to be seen a lot in CRT television pictures as deflection jitter.

You have to worry about low impedance, too (balanced pair helps).

[Chuck]

Phil,
Did you ever see the Tandberg cd player (1987) that cost over $1000.00
U.S. that had a plastic Philips chassis that never functioned
correctly even when new? I was upset when I bought a Philips with the
same chassis for $125.00 and had to return it. Imagine the flack we
got when selling this turd.

[Cydrome Leader]

Chuck <c...@dejanews.net> wrote:

> On Thu, 3 Dec 2015 06:34:55 -0600, "Mark Zacharias"
> <mark_za...@sbcglobal.net> wrote:
>
>>OK, so it appears there is very little to discuss on this group in areas
>>like repairing audio components, amps, receivers, power supplies, etc these
>>days.
>>
>>I "tune in" here almost daily and rarely find anything of interest to me.
>>

>>Maybe we could share some "war stories" of cool repairs we have done in the
>>past.
>>

>>Re-live some past glories?
>>
>>The first time you traced down a bad reset line for a microprocessor?
>>
>>That integrated amp that blew a channel about once a year until you caught
>>that bias diode occasionally opening up?
>>
>>Sansui 5000A's? (yuck)
>>
>>Crappy Euro caps in Tandberg tape decks?
>>
>>Those times you sweated whether you could even get this thing put back
>>together?
>>

>>Any more recent successs stories to brag about?
>>
>>C'mon, don't we all enjoy patting ourselves on the back, really?
>>
>>
>>Mark Z.

> The receiver tech was flummoxed by one of those large 1970s Pioneer
> receivers. It had a problem none of us had seen before and we were a
> high volume audio chain. There was slight audio distortion on both
> channels, only on FM. We all worked commission only so I was the only
> one to volunteer to help him out. To cut to the chase, the receiver
> had an over designed mute circuit that was 3 or 4 stages deep, At the
> deepest stage there was one of the Sanyo electrolytics that became a
> common failure item many years later which was slightly leaky.
>

> I've got another one. In the early 80s there were these 19" Hitachi
> tvs that ghosted. It looked exactly like a bad delay line. By that
> time I ran the TV service department for the same company. We had
> just switched over to the big box store concept and I was inundated
> with broken tvs. Out of desperation, I switched out the CRT and the
> ghosting disappeared. We sold 1000s of these sets and I saw the
> problem 3 more times.
>
> And another. Kenwood sold these Funai made cd changers that never
> worked properly. All of them would come back with skipping or not
> playing discs problems. Kenwood came out with 3 or 4 mods, none which
> worked. Sometimes they would work for months before they came back.
> Somehow I found out if the mechanism retaining springs were stretched
> so the mechanism didn't sag at all, the problem disappeared. Called
> up Kenwood and they put out a mod kit that included strong springs
> which also didn't allow any downward movement of the mechanism.

Was that the type with the CD cartridge, like a trunked automotive unit?
Those things were all such garbage.

[Jon Elson]

Mike Tomlinson wrote:

> En el artículo <vtm66b5hsssqq9u6s...@4ax.com>, Jeff
> Liebermann <je...@cruzio.com> escribió:
>
>><http://members.cruzio.com/~jeffl/nooze/support.txt>
>
> Good fun. Thanks for posting that.
>
> Number 10 reminded me of this:
>
> https://en.wikipedia.org/wiki/Lp0_on_fire
>

Ah, we had a couple of those. We had a fairly large 360 system at
Washington University. 1401 and 7094, then 360/50 and then 360/65.

One of the routines that made one think of CIA dead drops in the middle of
the night was the routine for printing paychecks. (I guess vendor checks
were similar, too.) They had the box of continuous form checks locked in a
bank vault in the basement of the administration building. The box was
taped shut with signatures across the seal. When they opened the box, two
people had to be present and they had to sign a log sheet with the serial
number of the top check. They carried the box to the computer center,
loaded it into the printer and the program printed a sample form with VOID--
VOID--VOID all across it, but other info in the right place so they could
align the forms. When all was OK, they told the program to print the
checks. Then, they had to fill out and sign the log sheet reporting which
forms serial # were used in the aligning process and the first and last
forms serial # of the printed check run. Then the whole process was
reversed to get the box sealed and locked into the vault. During the whole
process, nobody was ever supposed to leave the side of the printer.

Well, imagine the confusion when in the middle of the print run the printer
started sparking and set the continuous forms checks on fire! I heard about
this 2nd hand, but apparently the accounting guys were running around like
decapitated chickens! They didn't even know how to properly log what had
happened.

I'm pretty sure we had another paper on fire event, but it was just standard
print output that time.

Jon

[Chuck]

No. It was a 5 disc carousel. Kenwood didn't have a design in the
pipeline so they outsourced it.

[Cydrome Leader]

Sort of sad somebody messed up a carousel. The cartridge based changers
were infuriating.

Anything that requires extensive soldering and screwing around with that
medical type tape to open up, like portable tape/CD players and now
cameras suck too.

[mog...@hotmail.com]

Lawsuits over the years have shown their companies to be just as liable occasionally, too (like with Nomura, Sumitomo, Mitsubishi, Toyota, Honda, Mazda, Hitachi and others...) I think that things are done less purposely with regards to American markets, though.

[Ralph Mowery]

<mog...@hotmail.com> wrote in message
news:0d1e8a73-0190-4762...@googlegroups.com...

On Saturday, December 5, 2015 at 4:30:21 PM UTC-5, Chuck wrote:
> On Fri, 4 Dec 2015 07:13:43 -0800 (PST), mako...@yahoo.com wrote:
>
> >One of my favorite stories is from electronics lab in college.
> >
> >We had to build a small two stage transistor audio amp in the lab with
> >parts from the stock room, onto a protoboard like breadboard.
> >
> >My lab partners and I were experienced hams and got ours working in no
> >time , no problems.
>

At college I had a lab with the same thing. We designed simple circuits and
built them and took measurments on them. There were boxes of parts that
were suspose to be the same parts. Some of the parts were either bad or out
of spec. Not on purpose, they just got that way over the years. Me and a
person I was with usually could locate the bad parts and get our project
going first. Got to be a joke that the ones that got theirs to work had the
lucky box with all good parts for that design.

[mrob...@att.net]

Mark Zacharias <mark_za...@sbcglobal.net> wrote:
> Maybe we could share some "war stories" of cool repairs we have done
> in the past.

It's definitely not consumer electronics, but here goes.

I used to work at a company that made flight simulators. My official
job was writing code to make the navigation instruments display
correctly, according to the simulated position of the aircraft, which
frequencies the radios were tuned to, the position of circuit breakers,
etc.

Some of the laws of nature at that particular job included:

1) Techs string wire.

2) Programmers write programs.

3) Techs never make mistakes when stringing wires.

4) No programmer could ever possibly understand the intricacies of
stringing wires. Therefore, any complaints by programmers about the
wiring can usually be disregarded.

5) Any persistent complaints about the wiring can be remedied by telling
the programmers to work around it in the code.

Never being one to obey the laws of nature, I brought in my own meter
and checked things out when the sim didn't seem to work right. My boss
knew that I had something of a clue; I had been giving "how to read a
schematic" lessons to a few of my cow-orkers (in software) who were also
new hires or just wanted to know how. He basically told me that he
didn't mind me doing my own checks as long as I was careful with the sim
hardware, and that I should expect the techs to get mad at me if they
ever saw me doing it.

I couldn't get the right DME indicator to light up in one sim. (It was
a box in the instrument panel with three 7-segment displays and a couple
of buttons. It was supposed to display how far the airplane was from a
particular radio station.) After a few rudimentary checks of my code, I
wrote up a "right DME inop" trouble ticket. The technician wrote back,
"Wiring checks to print, DME sent for repair". Sure enough, there was a
hole in the panel. When it was again filled, I tried again...no joy. I
swapped the left and right indicators - hmm, the problem stayed with the
socket instead of following the indicator. I broke out the wiring
diagram and my own personal multimeter and started chasing around behind
the panel - no wires or pins for power on the right DME socket. (It was
something like a DB25 or DB37, with individual "crimp and poke"
contacts.) I dutifully re-opened the ticket, and the tech dutifully
wrote "wiring checks to print" and closed it again.

About this time, the sim was shipped to the site, even though it was
broken. The standard process was to completely build the sim at the
factory, test it out, ship it to the site, certify it, and put it in
revenue service. For sites that were far away from the factory, this
practice was generally followed, because it was expensive to ship people
to site to finish working on the sim. However, the site that was
closest to the factory (~3 hr drive) was notorious for the following:

Factory: We will have the sim done on $DATE.

Site: No no no! We've already sold time on that sim to customers on
$DATE-30days and we can't reschedule! We *must* have it here
sooner!

Factory: Why did you do that? The sim will not be done on
$DATE-30days. It will be broken and unusable for training.

Site: We don't care.

Factory: If we ship it at that time, it will suck.

Site: We don't care!!! Ship it shipit SHIPIT!!1!

Factory: <sigh> OK.

(time passes)
Site: Well you got the sim to us on time but it sucks! Everything's
broken and we can't put the customers on it! Fix it fixit
FIXIT!!1!

Factory: <sighs deeply, starts phoning rental car agencies and hotels>

So I get to the site and the site manager is bugging me about the right
DME indicator. I walk in to the site maintenance shop and tell the
techs there I need some connector pins, the crimper tool, some wire, and
a bench power supply. They are extremely wary of this as they have
experienced "programmers with screwdrivers" before, but they give me the
requested items and follow me into the sim, probably in hopes that my
body will shake and jerk in interesting ways as I electrocute myself.
I put the pins on the wires and put them in the (still vacant) slots on
the right DME connector. Wires run out under the panel to the power
supply, which temporarily gets the co-pilot's seat. Fire up the sim,
hit the power supply, and whaddayaknow - DME love for all. I
disappointed the techs, but the site manager was very happy.

I pointed out the relevant page in the wiring diagram book, so the site
techs could get it wired in correctly. I figured they had a lot more
experience than I did in fixing factory screwups. They were satisfied
with this, and I got to go home.

Matt Roberds

[Mike Tomlinson]

En el artículo <n4dume$d8b$1...@dont-email.me>, mrob...@att.net escribió:

>Factory: We will have the sim done on $DATE.
>
> Site: No no no! We've already sold time on that sim to customers on
> $DATE-30days and we can't reschedule! We *must* have it here
> sooner!
>
>Factory: Why did you do that? The sim will not be done on
> $DATE-30days. It will be broken and unusable for training.
>
> Site: We don't care.
>
>Factory: If we ship it at that time, it will suck.
>
> Site: We don't care!!! Ship it shipit SHIPIT!!1!
>
>Factory: <sigh> OK.
>
>(time passes)
> Site: Well you got the sim to us on time but it sucks! Everything's
> broken and we can't put the customers on it! Fix it fixit
> FIXIT!!1!

Why does that sound so horribly, horribly familiar?

Brrr. Memories I'd rather forget.

--
(\_/) Tyson Fury: #homophobe #bigot #throwback #missinglink
(='.'=) #neanderthal #misogynist #redneck #dickhead
(")_(")

[Mark Zacharias]

<mrob...@att.net> wrote in message news:n4dume$d8b$1...@dont-email.me...

Wow. Lots of times I'm too lazy to read to the end - but this was great!
Loved it!

mz

[Mark Zacharias]

How about another slant on "War Stories" ?

The least competent, most alcoholic, etc tech person you ever had to work
with or follow after they got fired?

When I was first starting in consumer electronics repair, (my first job in
the business, actually) I was hired to replace "Karl". He had a resume - in
the '70s a well respected shop paid for him to come over from Germany.

By my time however - apparently a broken down alcoholic.

He would "repair" tons of stuff, bill out huge amounts (paid on commision)
then abscond when the re-do's became too much.

I was charged with fixing his re-do's and generally cleaning up the chaos he
had left behind.

Next job - another shop. They had just fired the SAME GUY. Same situation.
Re-do's coming in one after another. Angry customers. Piles of screws and
small hardware in a pile on one corner of the bench. Dis-assembled units all
over the place, and I mean ALL OVER. A Teac A-4010 in about four different
parts of the shop. No pressure... I'd never even seen one before.

Next job - SAME DEAL. By now I was getting pretty good at
reverse-engineering other peoples screw-ups, but - really?

A couple examples:

Auto-reverse car cassette deck. He didn't have the correct drive belt, so he
had SUPER-GLUED the ends of the old belt together. Played about 2 mnutes, if
that.

A Marantz 1060 integrated amp (re-do) with a blown channel. He had substuted
a driver transistors with a similar package item. Unfortunately, the part he
used was a VOLTAGE REGULATOR IC and not even a transistor.

He had his "groupies" though. Some customers followed him from one job to
the next.

About 1987 Bang & Olufsen in Chicago contacted our shop for a reference on
this guy.

We were rolling on the floor!

Gave him an absolutely GLOWING reference. We could think of nothing funnier
than the prospect of this guy working for B&O.

(no he didn't get hired)


Good times.

[Chuck]

Mark,

In the early 70s there was a company that sold strips of rubber of
various sizes with a razor blade, jig and a tube of super glue that
was supposed to be used to make belts for consumer electronics
equipment. I had never seen super glue before so I tried it. Once.

[Jeff Liebermann]

>Any more recent successs stories to brag about?

If you enjoy reading such stories, there are quite a few in the "Made
by Monkeys" section of various trade magazines. These highlight
quality control and design failures:
<http://www.electronicsweekly.com/made-by-monkeys/>
<http://www.designnews.com/archives.asp?section_id=1367>
If you're planning on designing the next big thing in consumer
products, or are wondering why some things just can't be repaired,
these columns (blogs) should be mandatory reading.

[jurb...@gmail.com]

>"I was charged with fixing his re-do's and generally cleaning up the >chaos he
<had left behind. "

Steve's TV, I doubt they are still around. Quit, went back a couple of times. One time they needed bo TV techs but needed an audio tech. Figured, hell I'll give audio a whirl. Not that I hadn't done any, just not exclusively.

Well there is this whole big stack of recalls (or redos) from the last guy. The Delco 2000 series car stereos. The guy's bench setup had a common ground for the speakers and he blew the audio output chip out of EVEY ONE OF THEM.

These are true four channels radios but not quad. these are not some elcheapo LAXXXX six buck chip. They were DM-165 mostly and they were over twenty bucks each, and he blew BOTH of them in each radio.

That was one of my last commission jobs. I made money. And after that SNAFU was cleared up the boss(es) standing around said "We're finally making money on audio". That part was a bit hellish. Back then we didn't even have a Hakko and those Delcos were among the first things that (regularly) came in that two sided boards with plated through holes.

Every last one of them. With the type B tape decks in them the belt would break and it would not eject, so no radio either. So many customers decided to pry the tape out, breaking the cassette guides. The belt is a buck, a set of these plastic pieces it twenty. Even though they were assholes who cost themselves some money there, they did happen to notice when the front speakers didn't work anymore after they got it back.

And then they bring it back and because of the common ground the bench speakers would play the L-R like the back channels of a quasi quad unit and when you turn the balance to one side it would sound almost normal. "Nothing wrong with it". Yeah right.

You can't really work techs on commission anymore. Back then, so many repairs involved simple parts that it could work with a guy who is good. There were shops though that I would not. If I do not see a good parts department fuck that. I ain't coming in and diagnosing all this only to wait weeks to complete the job to get paid. What's more, forget the free estimate, I ain't doing it.

When the shop[ makes money, the tech makes money on commission. One place I did work commission worked out pretty well. I was running though some of my old shit and part time, one week I made $480 in 12 hours. One week I worked about 30 hours and took home $775. And that was in the 1980s. Later, that job converted to hourly, at a quite good rate. It was slightly less money but it was steady. I liked the money steady and they liked the fact that I could no longer refuse jobs.

And that paid off for them.

Actually, now this is a LONG time ago and at $23 an hour, they threw me a set I had already been stumped on before. they said it is a do or die. It may have been a contract job, and when you cannot fix a contract job that is very bad. You can't just refund the money, you have to buy them another TV.

This was an RCA CTC 169. (I should have put thios in my other post but did not recall it then) Intermittently it would start up with the OSD shifted and no sound. Now this was a normal symptom for this chassis and I do not recall what the fix was, but in this case where the OSD is usually shifted to the right, this one was shifted to the left. (or vice versa but you get the idea, the other way)

it would never do it with the chassis flipped up. About ten people resoldered almost every joint on the board to no avail.

RINALLY I got it. It was a weak 503 KHz crystal at the jungle IC. the hell you say ? Well when the micro tells the set to come on it expects a source to come up right away which is scan derived. this feeds the EPROM which then reads its contents into RAM with the specific setup info and settings.

I started noticing that when this happened, the HV did not come up immediately. What it was is the crystal was weak or whatever and the oscillator took too much time to start. The micro is only sensitive to that data for a limited time and the window was closed by the time the EPROM spoke up. That chassis had a system that is operable without an EPROM. When it is in that mode it uses a set of parameters that do not match the hardware installed. Actually I do not recall ever seeing a CTC169 without an EPROM, but other models did. Some of them would autoprogram first time they were turned on after being unplugged. Those were the elcheapo models, but of other chassis'. I guess they used the same micros or at least similar code in them though.

So we got :

No sound - 503 KHZ crystal for horizontal osc.
No sound - vertical shaping IC.
Loses blue and green after CRT replacement - adjust vertical height.

I'd like to see some weirder ones than that.

[Jeff Liebermann]

On Fri, 11 Dec 2015 10:46:52 -0600, Chuck <ch...@mydeja.net> wrote:

>In the early 70s there was a company that sold strips of rubber of
>various sizes with a razor blade, jig and a tube of super glue that
>was supposed to be used to make belts for consumer electronics
>equipment. I had never seen super glue before so I tried it. Once.

Those are still sold and work reasonably well:
<https://www.google.com/#q=o-ring+splice+kit>

The trick is to cut the o-ring or whatever at an angle. That does
three things:
- It increases the surface contact area so that the glue has a better
grip.
- It converts some of the stresses from tension to shear, where
cyanoacrylate adhesives are stronger.
- When used as a compression seal, crushing the glue joint does NOT
crack the rather brittle glue joint.

The only gotcha I've run into is dealing with tight turns such as very
small diameter drive pulleys. Cutting the o-ring at a large angle
causes the glue joint to be longer. Too long, and it will crack if
wrapped around a small pully. Just size the angle for covering no
more than about 60 degrees around the pully, and I think it should be
ok.

Note: Super glue doesn't work if there's little contact area, so
splicing thin and flat belts doesn't work. I've had some luck using
contact cement with these, but not reliably.

[whit3rd]

On Thursday, December 10, 2015 at 1:00:55 PM UTC-8, Ralph Mowery wrote:
> <mog...@hotmail.com> wrote in message
>
> At college I had a lab ... There were boxes of parts that

> were suspose to be the same parts. Some of the parts were either bad or out
> of spec. Not on purpose, they just got that way over the years. Me and a
> person I was with usually could locate the bad parts and get our project
> going first. Got to be a joke that the ones that got theirs to work had the
> lucky box with all good parts for that design.

I was teaching one such lab, with bar magnet/coil experiments, and had
an inspiration. I got some iron filings and sheets of paper, and
had the students lay the paper over their bar magnet and sprinkle
the filings over it.

There were a dozen bar magnets in the 'materials' box, and half of 'em had odd
fields. One had five identifiable poles. Using only the dipole-type
bar magnets, the class got better compliance than usual with the
expected behavior of poles and coils in motion.

[Adrian Tuddenham]

Mark Zacharias <mark_za...@sbcglobal.net> wrote:


> Maybe we could share some "war stories" of cool repairs we have done in the
> past.

I was called in unofficially to have a look at an X-ray machine in a
university crystallography lab, there was an intermittent fault which
shut it down after a few seconds of operation. The running time was
getting shorter and shorter and the manufacturers had given up on
finding the fault.

On the way there, I mentally ran through what I could remember about
X-ray machines (apart from the obvious dangers) and realised that most
of what I knew had come from reading my father's hand-written course
notes in the 1950s; they dated from when he was trained as an army
radiographerat the outbreak of WWII. I knew what an X-ray tube looked
like as a symbol, but what did one look like in reality?

On being introduced to the faulty machine, I glanced around the room and
saw a number of copper-and-glass objects on a shelf - and concluded that
they must be spare tubes. Luckily, the manufacturers had furnished a
full set of circuit diagrams and the lab had managed not to loose them,
so I knew what I was dealing with, even if I didn't initially know how
most of it worked. The circuits were all discrete components with
intermixed transistor, diode and relay logic.

By the end of the first day, I had gained a fair idea of how the power
supplies and safety circuits worked and had been instructed in the
necessary safety drill by the technician, so I was able to fire the
machine up and watch what happened. The fault showed up, but it all
happened so quickly that I wan't able to spot what was going on.

Luckily, on the morning of the second day, I happened to spot the tube
current meter flicker downwards and the voltmeter kick upwards just as
the fault occurred. Careful monitoring of the primary of the mains
transformer showed unstable mains voltage, which the control loop had
been over-compensating and then tripping out on over-voltage.

The cause was a burnt contact in the main contactor, so I stripped it
down and sandpapered the contacts, much to the amusement of the staff.

Fault cured - machine saved from the scrapheap.


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

[jurb...@gmail.com]

Been there done that. Good site. The name seems to imply it is a comedy site but it is not. I hope people are not too disappointed.

[Jeff Liebermann]

How to operate a tube caddy.

During the early 1970's, I ran a 2way radio service shop. Running it
was an accident because no sooner was I hired, everyone else either
quit or promoted themselves sideways, leaving me as the sole employee
and later as part owner. This condition lasted for a few months of
serious overwork, until I was finally able to hire an employee. The
shop:
<http://802.11junk.com/jeffl/pics/Old%20Repeaters/slides/PMC02.html>

A major part of the operation was maintaining a mountain top radio
repeater site:
<http://802.11junk.com/jeffl/pics/Old%20Repeaters/slides/Santiago-01.html>
When something went wrong, the ritual was to load up the company
pickup truck with everything imaginable, drive 12 surface miles to the
base of the mountain, drive 16 miles up a windy dirt road to the top,
fix something, and repeat the ritual in reverse. 6 to 8 hrs was the
typical round trip time.

Replacement tubes were carried in a tube caddy. For those who have
never seen a tube caddy, the individual tubes were stored in small
personalized cardboard boxes, inside a wooden carrying case like
these[1]:
<https://www.google.com/search?q=tube+caddy&tbm=isch>
My new employee would identify the dead or dying tube, extract a new
tube from the tube caddy, insert the new tube into the radio, insert
the dead tube into the cardboard box, and replace the box into its
place in the tube caddy. Do you see a problem here?

That worked for about 3 months when I discovered that my new employee
couldn't seem to fix anything. Various theories were offered, but
nothing worked. One day, my employee had a cold, so I had to do the
drive up the mountain. Oddly, I also couldn't seem to fix anything
either. Then, I noticed that some of the tubes I was using as
replacements were obviously ancient and really didn't belong in
service. Hmmm...

Upon returning to civilization, I tested almost all the tubes in the
tube caddy, and found that well over half were dead[2]. When I
mentioned it to my new employee, it took him a while to understand
what had happened. I suspected that the thought the tube caddy
somehow rejuvenated dead tubes. I resisted the temptation to thrash
him about the head, because he was bigger than me. I later found him
a job with a competitor.


[1] I still have a tube caddy full of tubes awaiting the demise of
semiconductors.

[2] Tube testing algorithm. If the tube tester says it's bad, it's
bad. If the tube tester says it's good, it still might be bad.

[Jeroni Paul]

jurb...@gmail.com wrote:
> Well I guess it is my turn.
>
> NAP bigscreen no sound - vertical control IC.
>
> Everything runs off the data and clock lines. This IC does the "S" correction and things like that pertaining to linearity. It is of course bus addressed. The one line, data or clock, doesn't matter, was clamping the signal down to like 2 volts. Leaky. That meant the data from the EPROM was not read when the unit got initialized so it did not know which sound system it had and never upped that.

I had a similar fault in an Universum CRT TV set. It came with an all white screen sympthom that I traced to the RGB decoder matrix IC holding its RGB outputs to 0V. Replaced the IC, no joy. It was I2C controlled and I even built a simple interface to send commands from the PC, it seemed to ACK fine and all looked right. If not initialized at turn on the raster remained black but as soon as the outputs were activated in any way it would go full white.
Finally found the problem: it received a sandcastle signal from the sync processor IC that had the top pulses too low so the RGB IC was not locking on them. The picture improvement IC also connected to this signal had a leaky input and was eating half the signal.

[Jeroni Paul]

Chuck wrote:
> In a similar vein to your remote story, we sold an $1800 Tandberg
> cassette deck that came to the shop over and over again for not
> responding to the transport keys. In the shop it always worked
> perfectly. I decided to go to the customer's house after work to see
> what the problem was. At his house, the keys didn't work. I spotted
> a light dimmer on the wall. Turning it off and the deck worked
> perfectly.

I have a SABA music system (radio + cassette + turntable + audio in/out plugs + remote control), time ago I had it connected to a desktop PC to play music from the PC. One day the printer attached to the same PC was taken out for repair due to clogged heads.

The next day I found the SABA turned on with the MUTE activated (the radio was selected so the FM display etc was all lit, but no sound). Since I never used to use the MUTE button and I was the only one at home to use that thing I was quite surprised. I unmuted it and turned it off, all appeared to work correctly. The same day in the evening the same again, that made it obvious it was not me. In the next few days the same kept happening at random times but never when I was there, and because it would turn on with the mute set I could not hear when it happened.

Finally one day it was off, I went to the kitchen and when I came back it was on and muted again, so I guessed a relation had to exist. Turned it off and went to the kitchen again - no joy. Repeated a few times and surprise - again on and muted. Some more experiments revealed that switching off the kitchen light sometimes would cause the SABA to turn on and activate the mute at the same time.

The kitchen light consists of two 36W fluorescent tubes, apparently the inductive kick at turn off found its way into the SABA digital controls. They were two rooms apart, so not exactly next to the kitchen switch or lights. The issue did not reoccur after I plugged the printer back.

[Jeroni Paul]

Mark Zacharias wrote:
> OK, so it appears there is very little to discuss on this group in areas
> like repairing audio components, amps, receivers, power supplies, etc these
> days.
>
> I "tune in" here almost daily and rarely find anything of interest to me.
>

> Maybe we could share some "war stories" of cool repairs we have done in the
> past.
>

> Re-live some past glories?
>
> The first time you traced down a bad reset line for a microprocessor?
>
> That integrated amp that blew a channel about once a year until you caught
> that bias diode occasionally opening up?
>
> Sansui 5000A's? (yuck)
>
> Crappy Euro caps in Tandberg tape decks?
>
> Those times you sweated whether you could even get this thing put back
> together?
>

> Any more recent successs stories to brag about?
>

> C'mon, don't we all enjoy patting ourselves on the back, really?
>
>
> Mark Z.

I was in a block of flats to look at a curious problem in their terrestrial TV reception. Whenever the communal stairs/hall lights were on, all TV sets in the block lost signal.
The stairs lights were controlled by a timer relay that kept the lights on for a few minutes after any push button was hit, so every time someone entered and hit the light the neighbors TV signal went out for a few minutes.

I started checking the terrestrial antenna head amplifier and found it lost mains power whenever stairs lights were on. I also observed that four or five lights in the stairs did not illuminate and some push buttons didn't activate the lights. That one had me thinking for a while and I drew this diagram to understand what could possibly be going on there:

Head amplifier wall plug
N L
| |
| |
|--light bulb--| |
|--light bulb--| |
|--light bulb--| |
X | |
|--light bulb--| |
|--light bulb--| |
|--light bulb--| |
| | |
| relay |
| | |
| +-----+
| |
N L
Mains supply

That turned out an accurate representation of the problem, I found "X" was a badly burned electrical terminal inside a connection box. With relay open, the bulbs happened to be in series in the neutral going to the head amplifier and because its small current draw it had enough voltage to work. With relay closed, only light bulbs before the break illuminated and the head amplifier got the L pole in the N wire through the non-working bulbs, so no voltage to work.

[Mark Zacharias]

Sometimes a small victory makes you feel just as good as a big one.

Picked up a somewhat non-functional Micronta 22-220A multimeter. A little
rough but the FET meter circuit worked - voltage readings weren't too far
off and the zero control did it's job so I knew all that stuff was OK.

But the resistance function acted as though there was a 4 ohm or so resistor
across the leads all the time, and the battery was draining at about 100 mA
in Ohms function even with no leads attached.

Of course the 9.1 ohm Rx1 resistor was bad, but replacing it did NOT change
the symptom.

After finding a schematic (not many out there...) I did find a component
labelled "SA1" shorted at 4 ohms or so. The item resembled an MOV and I can
only assume SA stood for spark or surge arrestor.

Removing it mostly fixed the ohms function, and I decided a couple of
back-to-back 25 volt zeners would offer enough protection to satisfy my
needs.

Still the ohms zeroing was erratic. Cleaning the function / range switch and
ohms pot til I was blue in the face did not resolve the problem. It was
kinda usable but it kept bugging me.

I tried putting a current meter in series with the test leads but couldn't
really get a usable correlation between pushing, poking wiggling the
function switch etc and the action of the meter which might zero fine, then
show up to several ohms even seconds later with probes shorted.

It occurred to me that I could put a resistor (say 4.7 ohms on this range)
across the probes and put a 'scope across that resistor to better see what
the DC voltage there was doing.

Oh, yeah. the voltage as viewed on the 'scope varied wildly and looked
"noisy" as the funtion switch was wiggled or tapped.

But I had cleaned that switch umpteen times.

Well, there was another switch - a leaf switch, going to the negative
battery terminal hiding under the front face and also actuated by the
function knob.

A quick cleaning of those contacts and the meter works like new.

A small victory to be sure, but made me feel as good as a big one.


Mark Z.

[Gareth Magennis]

"Mark Zacharias" wrote in message news:LFW7y.253701$4M.3...@fx17.iad...

OK, so it appears there is very little to discuss on this group in areas
like repairing audio components, amps, receivers, power supplies, etc these
days.

I "tune in" here almost daily and rarely find anything of interest to me.

Maybe we could share some "war stories" of cool repairs we have done in the
past.

Re-live some past glories?

The first time you traced down a bad reset line for a microprocessor?

That integrated amp that blew a channel about once a year until you caught
that bias diode occasionally opening up?

Sansui 5000A's? (yuck)

Crappy Euro caps in Tandberg tape decks?

Those times you sweated whether you could even get this thing put back
together?

Any more recent successs stories to brag about?

C'mon, don't we all enjoy patting ourselves on the back, really?


Mark Z.

A very distant fellow band member of mine once confided in me that he one
day discovered his next door neighbour had the same television that he had.
He had many hours of glee from sneaking up to their window and randomly
firing his remote control at their TV.


He also ended up being prosecuted for stealing commission cheques meant to
be mailed to our management company.

Not a particularly nice bloke.



Gareth.

[N_Cook]

On practical joking, this was to wind-up my parents , when I was aged
about 10.
A syncronous mains driven/timed mantle clock . I was intrigued by this
little flipper/kicker thing that operated when you turned on the power.
If you disengaged it with a match, then half the time , when switching
back on, the clock would go backwards.

[Ralph Mowery]

"N_Cook" <div...@tcp.co.uk> wrote in message
news:n4m1un$jkq$1...@dont-email.me...

>>
> On practical joking, this was to wind-up my parents , when I was aged
> about 10.
> A syncronous mains driven/timed mantle clock . I was intrigued by this
> little flipper/kicker thing that operated when you turned on the power.
> If you disengaged it with a match, then half the time , when switching
> back on, the clock would go backwards.

That reminds me of a clock we had when I was growing up. On the back was a
small wheel and you had to spin it in the direction you wanted the clock to
run when it was plugged in.

[MJC]

In article <EuadnXCyGaPJR_PL...@earthlink.com>,
rmower...@earthlink.net says...

If only one could "turn the clock" back and recapture one's long-gone
youth that way...

Mike.

[Phil Hobbs]

I wouldn't be 21 again on a bet.

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

[amdx]

On 12/14/2015 9:15 AM, Phil Hobbs wrote:
> On 12/14/2015 10:08 AM, MJC wrote:
>> In article <EuadnXCyGaPJR_PL...@earthlink.com>,
>> rmower...@earthlink.net says...
>>>
>>> "N_Cook" <div...@tcp.co.uk> wrote in message
>>> news:n4m1un$jkq$1...@dont-email.me...
>>>>>
>>>> On practical joking, this was to wind-up my parents , when I was aged
>>>> about 10.
>>>> A syncronous mains driven/timed mantle clock . I was intrigued by this
>>>> little flipper/kicker thing that operated when you turned on the power.
>>>> If you disengaged it with a match, then half the time , when switching
>>>> back on, the clock would go backwards.
>>>
>>> That reminds me of a clock we had when I was growing up. On the back was a
>>> small wheel and you had to spin it in the direction you wanted the clock to
>>> run when it was plugged in.
>>
>> If only one could "turn the clock" back and recapture one's long-gone
>> youth that way...
>>
>> Mike.
>>
>
> I wouldn't be 21 again on a bet.
>
> Cheers
>
> Phil Hobbs
>

On the other hand, a recent comic had an old man and a young child,
the child ask, "Grampa, how old are you?"
Grampa replied, "I'm 89 years old, and I don't recommend it!"
Mikek

[Phil Hobbs]

It's true, being really old is no fun either.

http://dilbert.com/strip/2008-01-30

But then I'm a Christian, so I don't have to hang on with my fingernails.

[Cydrome Leader]

Ha!

Was noise filtering on the always on printer was somehow supressing the
interference?

[Gareth Magennis]

"Phil Hobbs" wrote in message
news:99idndpGh9yHQPPL...@supernews.com...

On 12/14/2015 10:08 AM, MJC wrote:
> In article <EuadnXCyGaPJR_PL...@earthlink.com>,
> rmower...@earthlink.net says...
>>
>> "N_Cook" <div...@tcp.co.uk> wrote in message
>> news:n4m1un$jkq$1...@dont-email.me...
>>>>
>>> On practical joking, this was to wind-up my parents , when I was aged
>>> about 10.
>>> A syncronous mains driven/timed mantle clock . I was intrigued by this
>>> little flipper/kicker thing that operated when you turned on the power.
>>> If you disengaged it with a match, then half the time , when switching
>>> back on, the clock would go backwards.
>>
>> That reminds me of a clock we had when I was growing up. On the back was
>> a
>> small wheel and you had to spin it in the direction you wanted the clock
>> to
>> run when it was plugged in.
>
> If only one could "turn the clock" back and recapture one's long-gone
> youth that way...
>
> Mike.
>

I wouldn't be 21 again on a bet.

Cheers

Phil Hobbs

Youth is wasted on the young.

Being young again with an old mind though .......



Gareth.



Gareth.

[Jeff Liebermann]

About 3 weeks ago, I was blessed by the addition of a Samsung
Syncmaster 243T 24" 1920x1200 LCD monitor to my repair backlog. It
had been sitting around the donors office for a year or two, so nobody
could recall why it was retired. I plug it in and it appears that
everything is working. I have two similar LCD monitors at home for
running my flight simulator. A third monitor would make a start on a
wrap around cockpit window view. (actually 4 is about right).

So, I take home the monitor, being careful not to bash in the screen
like I did the last monitor I took home by planting the groceries dead
center in the middle of the panel. It arrive safely, I plug it in,
and nothing works. No power, no pilot light, no messages, no nothing.

I'm not exactly equipped at home to fix monitors, so I drag it back to
the office where it sat around for a few days. I plug it, and
everything works normally. I check for intermittents by beating on
the monitor, but nothing happens.

At this point, a sane and rational person would tear the monitor
apart, look for problems, probe around with a volts-guesser, determine
the culprit, and fix it. Nope. I'm out of bench space and have no
room to work on a big monitor. So, I drag the monitor home again, and
once again, it's dead on arrival. So, I drag it back to the office
for the 3rd time, where it once again works perfectly.

This would be a good time to guess the cause (although I haven't
really revealed enough info to make a proper deduction).

I still haven't ripped it apart to see what's going on, but I do have
a good guess what's wrong. It probably has the usual bulging
capacitor problem in the power supply. I keep the office at 72F (22C)
to keep the customers happy. At home, I prefer something around 65F
(18C). The workbench, where I do my testing is not very well heated,
and is probably colder. Outside temperature is now about 43F (6C).

Bulging electrolytics are detected by measuring the ESR, which
increases as they leak. Heating the caps lowers the ESR back down.
Cooling the caps raises the ESR back up. Incidentally, this is why
some devices run merrily when warm, but won't turn on when allowed to
cool off. The Samsung monitor is likely teetering between working
when warm, and not running when cold.

I'll disclose what was really wrong after I fix it, probably next
year.

[Jeff Liebermann]

One of the advantages of my office location is that it's very
centrally located. Within about 500ft is the intersection of 3
freeways, the main drag into Santa Cruz city, and smaller roads
leading directly to nearby cities. All roads lead to my office, which
is both a benefit and a problem. Besides making it easier for my
customers to drop in, it also attracts a motley assortment of people
that just happen to be driving by my dead end street, and just happen
to in the mood for trashing my day with inane conversation.

One memorable day, I had 4 of these visitors perched on benches and
chairs (I only have two chairs in the office to make sure they're not
very comfortable). I was working on replacing some caps in an ATX
power supply. Of course, I wasn't paying attention and accidentally
soldered the caps in backwards. With the cover off, I plugged in the
power supply, and continued the discussion with my visitors. Suddenly,
several of the caps decided this would be a excellent time to explode
and launch oily confetti all over the office. Everyone, except me,
dived for cover under or behind tables and boxes. I just continued
talking as if everything was perfectly normal and nothing unusual had
happened. The visitors soon made a rather hasty exit. Oddly, they
must have told their friends, because my office was free of unwanted
visitors for at least a week or two.

[Ralph Mowery]

"Jeff Liebermann" <je...@cruzio.com> wrote in message
news:0r9v6b5fq4unaprjl...@4ax.com...

Going to look bad when it is a bad power cable or socket.

Could be the capacitors. A number of years ago when the bad capacitors were
in many computers a friend had a computer in his basement that sometimes
came on and sometimes not. He left the cover off of it and would put a
light bulb next to the computer to heat it up. The computer wold come on
and work fine unless he shut it off , then he had to heat it up again with
the light bulb.

[Clifford Heath]

We had a couple of old Fujitsu "Eagle" disk drives - 500MB or so -
inherited when we started a company in 1990. These were about 25-30kg,
and 500x350x700mm in size - so you needed two strong sets of hands to
get them on and off the rack mountings (they were on slides).

Anyhow, as they got older, the spindle bearings became sticky, so they
wouldn't spin up after a power fail that was long enough for them to
cool down. We used to get them off the racks, with one bloke at each
end, then power them up and give a sudden lateral rotation to break the
stiction of the bearings. Quite a risky business, coordinating two
blokes to do that suddenly enough without dropping the drive, but it
worked a number of times before we made enough money to afford to
replace them.

We started a software company with 25 initial employees (staff buy-out)
and a grand total of 2.2GB of storage - in the entire company. Imagine that!

Clifford Heath.

[Jeff Liebermann]

On Tue, 15 Dec 2015 11:09:55 -0500, "Ralph Mowery"
<rmower...@earthlink.net> wrote:

>Going to look bad when it is a bad power cable or socket.

Nope. Both passed the wiggle test.

>Could be the capacitors. A number of years ago when the bad capacitors were
>in many computers a friend had a computer in his basement that sometimes
>came on and sometimes not. He left the cover off of it and would put a
>light bulb next to the computer to heat it up. The computer wold come on
>and work fine unless he shut it off , then he had to heat it up again with
>the light bulb.

I'm getting that now on my home desktop computah. I don't bother to
heat the house much at night. When I wake up, it's about 45F (7.2C)
inside the house. When I turn on my desktop computah, the fan makes
some odd noises but eventually quiets down. The hard disk seems to
boot normally, but usually some programs add oddly or crash. I reboot
and they then act normally. It's probably read errors on the hard
disk, but SMART shows nothing interesting. At this time, I boot to
the BIOS screen, wait about 10-15 mins, and then boot normally.

[Clifford Heath]

On 16/12/15 10:15, Jeff Liebermann wrote:
> On Tue, 15 Dec 2015 11:09:55 -0500, "Ralph Mowery"
> <rmower...@earthlink.net> wrote:
>
>> Going to look bad when it is a bad power cable or socket.
>
> Nope. Both passed the wiggle test.
>
>> Could be the capacitors. A number of years ago when the bad capacitors were
>> in many computers a friend had a computer in his basement that sometimes
>> came on and sometimes not. He left the cover off of it and would put a
>> light bulb next to the computer to heat it up. The computer wold come on
>> and work fine unless he shut it off , then he had to heat it up again with
>> the light bulb.
>
> I'm getting that now on my home desktop computah. I don't bother to
> heat the house much at night. When I wake up, it's about 45F (7.2C)
> inside the house. When I turn on my desktop computah, the fan makes
> some odd noises but eventually quiets down

Take the fan out and refit it, rotated 90 degrees.

The bushings wear the holes elliptical, and the rotation changes the
vibration modes.

[Ralph Mowery]

"Jeff Liebermann" <je...@cruzio.com> wrote in message

news:kf717bp4p5j377q45...@4ax.com...

> > I'm getting that now on my home desktop computah. I don't bother to
> heat the house much at night. When I wake up, it's about 45F (7.2C)
> inside the house. When I turn on my desktop computah, the fan makes
> some odd noises but eventually quiets down. The hard disk seems to
> boot normally, but usually some programs add oddly or crash. I reboot
> and they then act normally. It's probably read errors on the hard
> disk, but SMART shows nothing interesting. At this time, I boot to
> the BIOS screen, wait about 10-15 mins, and then boot normally.
>
>

If I got out of bed and it was 45 F, I would be looking into the heating
system first. I don't function when it is that cold.

Sounds like you may want to look into a solid state drive for the computer
so it will start up cold.

[thekma...@gmail.com]

If I got out of bed and it was that cold, I would be looking
into some INSULATION first! Something 'Murricans seem
to be averse to, even after decades of evidence in favor
of it.

[Michael A. Terrell]

I've woken up to -40F, during survival training.

I've installed more fiberglass batts than I care to think about,
starting in the early '60s.

[thekma...@gmail.com]

8:29 PMMichael Terrell wrote:
"- show quoted text -

I've woken up to -40F, during survival training.

I've installed more fiberglass batts than I care to think about,
starting in the early '60s. "

Then you must almost never turn your heat on.

'Murricans, thinking they all tough by never
using heat in the winter...

[Jeff Liebermann]

On Tue, 15 Dec 2015 17:21:14 -0800 (PST), thekma...@gmail.com
wrote:

>If I got out of bed and it was 45 F, I would be looking into the heating
>system first. I don't function when it is that cold.

<http://802.11junk.com/jeffl/pics/home/slides/wood-burner.html>
<http://802.11junk.com/jeffl/pics/home/slides/firewood-2015.html>

Below about 45F, I have problems working, especially when I'm walking
around the house in pajamas and no shoes. I do it often and it
doesn't bother me much. However, that requires that I keep moving,
which is often difficult in front to the computah. So, I fire up the
wood burner and run the temperature up to 60 to 70F.

>Sounds like you may want to look into a solid state drive for the computer
>so it will start up cold. "

An SSD is in the works. The problem is that every time I buy one for
myself, some customer arrives and needs it more. Since prices are
dropping, I don't mind delaying my SSD upgrade. However, for the
present situation, I'm looking into an adjustable cat or dog warming
electric blanket. I had a mysterious data corruption problem about a
month ago, when it began to become cold, that was probably due to the
startup problem. I recovered fairly easily, but it burned too much
time.

>If I got out of bed and it was that cold, I would be looking
>into some INSULATION first! Something 'Murricans seem
>to be averse to, even after decades of evidence in favor
>of it.

This is not a conventional house:
<http://802.11junk.com/jeffl/pics/home/slides/BL-house3.html>
Insulation is possible, but there are other priorities that come
first. Eventually, I'll need to build up the roof, which is where
insulation will do the most good. One of my neighbors did that to
their house that was similarly built, and it worked very well.

[Michael A. Terrell]

No, but then I live in Florida. :)

I have a 1000W electric heater, for the rare times that it is in the
30s for several days in a row.

[et...@whidbey.com]

On Tue, 15 Dec 2015 18:05:36 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

Greetings Jeff,
Your house makes me nostalgic. I grew up on the other side and at the
base of the Santa Cruz Mountains in Saratoga. Hitchhiked over to
Santa Cruz and then either north or south, depending on my mood. North
for the beaches, south for Capitola. Or right into Santa Cruz for the
Boardwalk. I hiked all over the Santa Cruz Mountains, in the summer I
hiked and camped as much as possible. Dug for sharks teeth in Scott's
Valley. The longest one I found was over three inches long but was
broken into two parts. It was in a dry rivulet in the sand parking lot
where we, and everybody else, dug for sharks teeth. I pretty much
stopped hitchhiking when it became nearly impossible to get a ride
because of that crazy guy who was killing hitchhiking girls. His mom
and her friend too. Buried their heads under stepping stones in the
yard. I think he was named Edmund Kemper. I remember buying chilled
dungeness crab, butter, sourdough bread, and beer and sitting with
friends on a dock eating it.
Cheers,
Eric

[Dave Platt]

In article <3pg17bd61th4vopib...@4ax.com>,

Jeff Liebermann <je...@cruzio.com> wrote:

> However, for the
>present situation, I'm looking into an adjustable cat or dog warming
>electric blanket.

Cat's aren't particularly adjustable, warmed or otherwise. They're
notoriously stubborn.

[Jeff Liebermann]

Cat warmer:
<http://802.11junk.com/jeffl/pics/drivel/slides/Cat-warmer.html>
Actually, that's the neighbors cat. She typed "don't you dare try to
move me" on the keyboard as a warning. I found a different computer
to work on.

Incidentally, the noisy fan on cold start turned out to the small fan
on the video card. Cleaning and switching to a multi-viscosity oil
change seems to have solved the problem.

[Jeff Liebermann]

Once upon a time, I was temporarily put in charge of marine radio
manufactories production test department while they searched for
someone to replace my predicessor, who had apparently gone missing,
insane, or both.

Among the test techs was one who followed instructions dilligently,
but usually failed to understand what was expected. The techs were
told that in the transmitter RF chain, if they couldn't identify which
device lacked sufficient gain, they could just replace each device in
turn until the culprit was found. This was possible because there
were only 7 devices involved, and the most likely culprits were the
cheap TO-92 devices found at the oscillator end of the chain.
Unfortunately, that was not communicated to this individual, who
proceded to replace devices starting with the rather expensive 25 watt
VHF RF output transistor. Nobody said noticed until I went to the
parts room to replace a 25 watt device that I had blown up in
engineering, and was informed that production test had grabbed all the
available stock. I also noticed that someone had prefixed some of the
printed test procedures to include turning the power on to the test
equipment. I survived for about a month and was very happy when the
company finally hired someone to replace me.

[Ralph Mowery]

"Jeff Liebermann" <je...@cruzio.com> wrote in message

news:nvt57b1mcjqrqjb7j...@4ax.com...

> Once upon a time, I was temporarily put in charge of marine radio
> manufactories production test department while they searched for
> someone to replace my predicessor, who had apparently gone missing,
> insane, or both.
>
> Among the test techs was one who followed instructions dilligently,
> but usually failed to understand what was expected. The techs were
> told that in the transmitter RF chain, if they couldn't identify which
> device lacked sufficient gain, they could just replace each device in
> turn until the culprit was found. This was possible because there
> were only 7 devices involved, and the most likely culprits were the
> cheap TO-92 devices found at the oscillator end of the chain.
> Unfortunately, that was not communicated to this individual, who
> proceded to replace devices starting with the rather expensive 25 watt
> VHF RF output transistor. Nobody said noticed until I went to the
> parts room to replace a 25 watt device that I had blown up in
> engineering, and was informed that production test had grabbed all the
> available stock. I also noticed that someone had prefixed some of the
> printed test procedures to include turning the power on to the test
> equipment. I survived for about a month and was very happy when the
> company finally hired someone to replace me.
>

Always start with the most expensive part. If it is not bad, it will be
when it is ripped out.

I had a Toyota that started running vrey bad with about 130,000 miles on it.
I repalaced the simple things like the plugs, wires, coil and fuel filter.
Nothing helped. From there a Autozone trouble shooting chart indicated a
sensor that was about $ 500. I took it to the local Toyota dealer and let
them look at the problem as I did not want to spend $ 500 and not need that
part. They kept it about 3 weeks and changed a few other parts including
the spark plug wires as I did not use Toyota wire. Finally they changed
that $ 500 sensor and it ran like it should. I would have thought a dealer
could run some tests but seems like they were just parts changers. Really
ticked me off as they had put on about $ 150 worth of parts that were not
needed and still charged me for them not counting on the 3 weeks it took
them.
It may have taken longer but I emailed the Toyota company about how bad the
service was at he end of the second week and got back a very nice email from
them .

[Jeff Liebermann]

One of my customers in the computah repair business own a large house
that had been converted to college student housing. My guess is about
15 students crammed into every possible available space. I was hired
by the owner to maintain the Comcast internet, NAS server, printers,
phone system, wiring, and wi-fi, which are all part of the package.
The prime directive was to do everything necessary to prevent the
students from burning down the house, which I interpreted to mean not
let them make any changes or additions to the wiring or equipment.
That has worked fairly well by the honor system for about 8 years.

This morning, I get a phone call that the internet and some of the
phones are down. Upon interrogation, I determine that some of the
"makers[1]" in the house had "optimized" the performance of the
Comcast cable modem and VoIP systems yesterday. My initial guess was
that they had managed to scramble the ethernet cables on the 24 port
managed switch running several VLAN's. Unlike ordinary ethernet
switches, a managed switch with traffic logging, required that the
correct cable be connected to the correct port.

I had previously suggested that someone should take photographs of the
wiring for this exact purpose. Amazingly, the students found the
flash drive in the envolope that I had place in plain sight, and were
able to display how things were wired before the system was
"optimized". They were able to bring things back online in only a few
additional minutes (I could see the switch come up from home via SNMP)
and only waited a full hour before someone bothered to phone me that
it was fixed and I need not waste a service call to the house.

With such a wonderful example of initiative and organized
troubleshooting, I think there may be hope for our next generation of
our country's leaders.


[1] Make trouble, make a mess, make love, make things break, make a
quick exit, etc...

[Jeff Liebermann]

On Thu, 17 Dec 2015 13:30:22 -0500, "Ralph Mowery"
<rmower...@earthlink.net> wrote:

>Always start with the most expensive part. If it is not bad, it will be
>when it is ripped out.

Never do anything that can't be undone.

>I had a Toyota that started running vrey bad with about 130,000 miles on it.
>I repalaced the simple things like the plugs, wires, coil and fuel filter.
>Nothing helped. From there a Autozone trouble shooting chart indicated a
>sensor that was about $ 500. I took it to the local Toyota dealer and let
>them look at the problem as I did not want to spend $ 500 and not need that
>part. They kept it about 3 weeks and changed a few other parts including
>the spark plug wires as I did not use Toyota wire. Finally they changed
>that $ 500 sensor and it ran like it should. I would have thought a dealer
>could run some tests but seems like they were just parts changers. Really
>ticked me off as they had put on about $ 150 worth of parts that were not
>needed and still charged me for them not counting on the 3 weeks it took
>them.

I had almost the same situation, except it was the rear oxygen sensor.
The dealer wanted to replace the very expensive catalytic converter.
The dealers computer diagnostics all pointed to the catalytic
converter. They even called the factory service support number, which
confirmed that the diagnostics conclusively pointed to the catalytic
converter. However, I was able to listen to this conversation and
detected considerable uncertainty and lack of competence on everyones
part. Something seemed wrong, so I decided to do some checking. The
internet was full of the usual mix of wisdom and useless garbage, but
I did manage to find an article suggesting that the rear oxygen sensor
tends to get contaminated by various exhaust products, and that since
it's two orders of magnitude cheaper than a catalytic converter, it
should be replaced first. I replaced it, and all as well.

I was curious as to what had just happened, so I went back to the
dealer, told them the story, and asked a few questions. Basically,
there is nobody in the system that knows how to troubleshoot a vehicle
without totally relying on the computerized hardware. The programming
is not intended to nail down the exact cause of a problem, only the
most probable causes, expecting the dealer to replace things in a
rational and logical order based on their experience. In other words,
the computer supplies a shopping list that usually includes a large
number of irrelevant replacement parts and procedures. When calling
factory service support, they don't have experienced techs on the
phones. They just read the computer screen. I was also told that it
was amazing that the diagnostics programs worked because the factory
was constantly making changes and improvements that affected
recommendations.

In my distant past, I had the displeasure of integrating BITE (built
in test equipment) in some radios. The test system caused more
failures than it detected. The diagnostics could be easily mislead,
producing insane results. Even worse, it could not diagnose itself.
All I can say is that such diagnostics are NOT easy to do, especially
with a moving target, such as an automobile.

[Ralph Mowery]

"Jeff Liebermann" <je...@cruzio.com> wrote in message

news:v5067bt25cgtgs9kb...@4ax.com...

>> I was curious as to what had just happened, so I went back to the
> dealer, told them the story, and asked a few questions. Basically,
> there is nobody in the system that knows how to troubleshoot a vehicle
> without totally relying on the computerized hardware. The programming
> is not intended to nail down the exact cause of a problem, only the
> most probable causes, expecting the dealer to replace things in a
> rational and logical order based on their experience. In other words,
> the computer supplies a shopping list that usually includes a large
> number of irrelevant replacement parts and procedures. When calling
> factory service support, they don't have experienced techs on the
> phones. They just read the computer screen. I was also told that it
> was amazing that the diagnostics programs worked because the factory
> was constantly making changes and improvements that affected
> recommendations.

At work there is a pipe that has about 150 psi of air on it and about 2
inches in diameter. This goes to a regulator that cuts it to about 75 psi
and then to a a control valve that is ran by a computer. This regular has a
habit of getting water in it and in the winter time turning to ice. I got a
call that the system was not working correctly so I cleared the ice from the
regulator. Then an engineer wanted me to rebuild or change out the control
valve because it was not working. I told her that I was not going to do it
unless there were more problems. She got very mad at me and told me that
her data from the computer said the control valve was not working. I told
her I did not care what her old data said, it was not the control valve.

The control valve can not control anyting if no air is getting to it for it
to control.

Had a lot more trouble out of some of the production engineers because of
the computer. The process probably monitored over 1000 points and stored
that data for a month. That data could be called up in a graphical form.
Only problem is some of the data points may be 1 to 5 moments apart.
Something could hapen and would not be caught during that time frame. Then
it would look like something other than the origional problem was the cause.

Computers are good,but you have to undestand what they are trying to tell
you and sometimes they are just wrong.

[pf...@aol.com]

Um.... Um....

Have you checked the receptacle at home? And for proper polarity?

Some monitors will not function if not properly polarized. Just a thought.

Peter Wieck
Melrose Park, PA

[jurb...@gmail.com]

>" Basically,
>there is nobody in the system that knows how to troubleshoot a >vehicle
>without totally relying on the computerized hardware. The >programming
>is not intended to nail down the exact cause of a problem, only the
>most probable causes, expecting the dealer to replace things in a
>rational and logical order based on their experience. "

Not even that. I think they may have been trying to rake you over the coals. As far as I know, there is no code for "catalytic convertor". the second O2 sensor is supposed to detect slightly less oxygen than the first one. This assures the cat is installed and operating. the codes them selves read something like "O2 sensor #2 reading rich", or lean. Anyone with a brain should logically replace that first. Incidentally, for this system to work, it MUST waste some fuel by making it over rich. If the mixture is stoichometric, the catalytic has nothing to do. But that is a bit easier on the valves and a few other components.

Catalytics either get clogged or burnt out. Something has to happen, prolonged driving with a misfire for example. I don't know about you, but when I drive, I want the car to run right. If it has a miss I can't stand it. If anything I can't stand it. If it burns oil I junk it. (that's why I prefer GM, seems their engines and trannies last, problem is they fell out of the damn car back in the 1980s)

You know, if the auto service business was like the consumer electronics service business, they would have pretty much had to put that cat in for free, or lied to you and put the O2 sensor in for free. Guess which. And let's not even get started about doctors, them fuckers cut off the wrong leg and expect to get paid. And that is pretty bad, because if you have one leg there ARE solutions whereby you can walk. If you have no legs that is it. I hope the guy they did that to is the richest MF sitting in the world.

But anyway, for a time I was the go to guy on hard faults in cars. (I also learned that you can CLEAN an O2 sensor) Buddy brings me his Cutlass, one of the last years you could get the bulletproof 4-151 engine. Good reliable car. Runs like shit. It REALLY REALLY acts like low fuel pressure. (a later paragraph will discuss that) Alot of cars had low fuel pressure and would start and idle, and crawl but not run. Slow fuel delivery was a big thing for a while. But that has been checked. It has also been to Mr. Goodwrench for a fifty buck diagnosis and they said to replace the engine.

They didn't know who the fuck they were talking to. They were trained to replace parts for fifty bucks an hour, we degreed cams, we had cranks machined down a thousandth or two and had them hard chromed back up to size. This is like having a forged crank, in fact better in some way. the olman had a 283 that did 9,400 RPM with a Racer Brown roller cam, ONE RPM higher it would wipe out bearing number one. They tried many things but at 9,400 RPM the laws of physics takes over and there was nothing you could do.

So anyway I drives the car up down the street, it cannot get out of its own way. Checking things out, I find the two possibilities are this crank sensor which is a bitch to change, or it jumped time. I took the air cleaner off and revved it up, and during part of the stroke it was spitting the injected gas out the top.

I said "Tear down for timing chain". (This guy was also a competent mechanic but this was a tough case) He said that they said this car does not have a timing chain, it has gears.

The next day he shows up and throws the tensioner on my kitchen table. Doesn't have a chain eh ? What kind of gears need that kind of tensioner ?

Another time my ex-lawyer had this pickup truck, I forget the make and model but it was a cheapie. It had linear torsion bar suspension, which means all the front end parameters are different. He had a tow hitch on a tow bar on the front so he could tow it with his camper. He said this is the only truck I could find that you could back up without the steering wheel whipping to a lock. It would track, and back up nicely so he wanted to keep it. Go camping and take your car with you kinda thing.

Maybe a year or so before he had the timing belt replaced. It would intermittently run like shit, not start, whatever. Nobody could figure it out.

Turns out the dodo who did the belt had lost the woodruff key and replaced it with an American version which was a bit too small. Over time it sheared, and the crank went where it wanted. Literally like 180 degrees off.

Now that is hard to detect. But we did detect it. We had to drive it too, apparently the inertia of revving and idling made it do it. Eventually we caught it, at one time the timing marks are right, and then they are wrong. W T F !

The wrong woodruff key had already mauled the crank so we brazed one in. You don't want to weld something like that in case it ever needs a front crank seal, but the brazing, and we thought about this, would stop the movement which was responsible for the failure because it just kept wearing away at it. Every compression and then power stroke moved it as this key was between the crank and the damper.

OK, that is not necessarily consumer electronics but others had looked at the thing coming up with all the wrong diagnoses. So it already had brand new plugs, module, sensors, wires, high performance lugnuts, the works.

How come some people are responsible if their diagnosis is incorrect and others are not ?

[Jeff Liebermann]

On Fri, 18 Dec 2015 07:49:23 -0800 (PST), "pf...@aol.com"
<pf...@aol.com> wrote:

>Um.... Um....

Who when where how why what?

>Have you checked the receptacle at home? And for proper polarity?
>Some monitors will not function if not properly polarized. Just a thought.

I don't think that's the problem of I would have been electrocuted
long ago. However, it was worth checking, especially since I did my
own wiring. So I dug out my tester:
<https://en.wikipedia.org/wiki/Receptacle_tester>
and walked it through the maze of power strips and extension cords.
Everything tests just fine.

[Mark Zacharias]

>> Any more recent successs stories to brag about?
>>
>> C'mon, don't we all enjoy patting ourselves on the back, really?
>>
>>
>> Mark Z.
>
> **I recall the first time (1980-ish) I discovered those fusible resistors
> that go high after a few years. With no obvious signs of distress. Now I
> just head straight for the buggers.
>
> Then there's those low value (</=47 Ohms), 1/4W cracked carbon resistors
> that go O/C when subjected to ca. 60+ Volts with no signs of burning
> (Marantz 1200b, 240, 250M, 500 models). Over the years, I learned to
> suspect any resistor over the value of 100k, if the circuit is displaying
> some kind of mysterious fault that cannot be explained by a semiconductor
> failure or cap leakage.
>
> --
> Trevor Wilson
> www.rageaudio.com.au
>
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
>
>

A brand new "war story".

As I am nearing the end of my career, I wonder if any one unit will be the
high water mark so far as feeling the satisfaction of fixing a really tough
one.

This may be it.

A Yamaha M-80 power amplifier. I've worked on a few in the past - difficult
but doable.

I've always thought that "M-80" was a humorously ironic model number for an
amplifier so flammable.

Initial inspection:

Burned resistors on both channels, a vented 1000uF 100v cap (one of a pair)
on the main board, lots of brown glue, some green corrosion visible on
component leads.

Strangely - only one output transistor was bad. I knew this was going to be
a tough one but I figured I could do it - just give the customer a pretty
high estimate.

Replaced those larger caps, lots of bad drivers, pre-drivers, signal
transistors, several burned and corroded resistors, one bias transistor.

Replaced the one bad output and it's mate. I figured the same current ripped
through both, so I wanted at least do that.

I knew the speaker relays would need service, so I took them out of order
and did that job.

Bringing up on a variac, the fires were out, bias adjusted OK, but no sound.
Another bad resistor.


Replaced this, but now there was a -86 volt(!) offset. Couple more bad
resistors.

Each time a component replaced it was necessary to monitor bias when
bringing it up.

Bring it up again, no offset but one channel oscillates. Fine. Trace down
and replace the bias transistor on that channel that was breaking down.
Replace it and: one channel low in gain, approximately 1/2 the other
channel.

Replace a bad 3.9K 1/2 watt resistor in the feedback loop. That was easy.
NOPE.

Now BOTH channels oscillate like crazy. Apparently a larger 3.9K 2W resistor
was corroded and got nudged while replacing the other. Replaced that. No
more oscillation. NOW:

Still no change on the gain problem.

Bad 430 ohm resistor hiding UNDER a power resistor, and not even visible
until the other was removed.

Unit now repaired and functioning properly.

This thing took approximately five whole days worth of bench time.

I'm going to spend a very generous amount of time patting myself on the back
for this one.


Mark Z.

[Trevor Wilson]

**All for an amp worth, what(?), $300.00? It can be a bugger of a
business. How much can you charge your client? $200.00?

On the flip side, I did a couple of really ancient (ca. 1972) Accuphase
amps recently. The client was willing to spend around $700.00 on each.
He bought them for a song and they typically sell for a couple of Grand
on eBay.

[John-Del]

>
> Any more recent successs stories to brag about?
>
> C'mon, don't we all enjoy patting ourselves on the back, really?
>
>
> Mark Z.

Okay, one more. True story... This wasn't so much a difficult repair as it was the circumstance. 1980, hot summer day and my new girlfriend (who would be my wife) is having her HS graduation party when her parent's early 70s tube Magnavox console blacks out in a cloud of smoke leaving a clean horiz line. I was 21 at the time and looked younger, but of course being a TV tech I was asked to look at it. I pulled the chassis out and the area around the vert centering control was pitch black. That and the cigarette smoke and wood stove deposits made seeing what else was burned nearly impossible.

I borrowed the garden hose and a bottle of Fantastik (TM) and soaked the bottom of the chassis and rinsed so it sparkled, then left it out front in the hot sun. Later in the afternoon I put in two 10 ohm 5W resistors in place of the vert cent control and put it together, touched up the height and lin and it worked fine for a few more years.

When my father in law tells the story, he said that when he saw me hosing out the TV guts in the front yard he was thinking "oh sh$t I'm going to have to buy a new TV tomorrow".

[Mark Zacharias]

"Trevor Wilson" <tre...@SPAMBLOCKrageaudio.com.au> wrote in message
news:dhf4nv...@mid.individual.net...

After an initial assessment, I gave the customer an approximately 300.00
estimate.

Midway through the process I advised him it would be more.

Billed out at 400.00.

He hasn't picked it up yet, but it's part of a set with the preamp, tuner,
cd, and cassette so I'm not too worried.

Yeah - these days you take what you can get.

I was pretty confident I could fix it, but one problem kept hiding behind
the last one, and oscillation problems kinda turn my knees to jelly.


Mark Z.

[Mark Zacharias]

"John-Del" <ohg...@aol.com> wrote in message
news:78c200c3-b710-43b0...@googlegroups.com...

>Okay, one more. True story... This wasn't so much a difficult repair as it
>was the >circumstance. 1980, hot summer day and my new girlfriend (who
>would be my wife) is >having her HS graduation party when her parent's
>early 70s tube Magnavox console blacks >out in a cloud of smoke leaving a
>clean horiz line. I was 21 at the time and looked younger, >but of course
>being a TV tech I was asked to look at it. I pulled the chassis out and
>the area >around the vert centering control was pitch black. That and the
>cigarette smoke and wood >stove deposits made seeing what else was burned
>nearly impossible.

>I borrowed the garden hose and a bottle of Fantastik (TM) and soaked the
>bottom of the >chassis and rinsed so it sparkled, then left it out front in
>the hot sun. Later in the afternoon I >put in two 10 ohm 5W resistors in
>place of the vert cent control and put it together, touched >up the height
>and lin and it worked fine for a few more years.

>When my father in law tells the story, he said that when he saw me hosing
>out the TV guts in >the front yard he was thinking "oh sh$t I'm going to
>have to buy a new TV tomorrow".

Same thing happened to my younger brother when our family was visiting the
family of the older brother's wife.

Zenith TV died. My younger brother, who was either still in tech school or
early in his career, tore the set down to bits and pieces right there on the
living room floor, puzzled over it a bit, the light came on, ran down to the
Zenith distributor, picked up a part, got back over there and finished the
repair.

Two families (not to mention the two brothers) were sweating bullets on that
one.


Mark Z.

[thekma...@gmail.com]

John-Del wrote: "When my father in law tells the story, he said that when he saw me hosing out the TV guts in the

front yard he was thinking "oh sh$t I'm going to have to buy a new TV tomorrow".

Good story with happy ending! Nowadays most folks
won't let me adjust their PICTURE menus for them,
let alone go component level. Sets are so reliable
today, with consistent image quality, yet people wonder
why they burn out after only 3-5 years.

Backlit TVs(LCD, LED) require a backlight to be seen,
and very often this setting, along with the others, are
left in factory/showroom mode, shortening the life of
the appliance. Getting set owners to understand this
basic fact, along with the benefits of correct setting of
the basic adjustments(brightness, contrast, color, etc),
is well-nigh impossible! A $300 full calibration is often
not necessary to achieve these goals.