90V B battery question.

[Michael A. Terrell]

Has anyone measured the current from the B battery section in a Z985
battery for a Transoceanic, or a Zenith 6G001/6C40 (Long Distance) which
uses the following tubes:
Type Plate current from data sheet
1-1LA6 0.55 mA
1-1LH4 ???????
2-1LN5 1.60 mA
1-3Q5G/GT 8.50 mA

This gives me 12.25 mA for four of the five tubes. The 1LH4
datasheets I have don't show any spec for plate current


The Zenith 6G001/6C40 is on Riders Zenith page 15-30 and 15-31.


I want to build a small inverter to run the radio off a rechargeable
9.6V NiMh battery after it's repaired. A drop in replacement for the
original battery with a built in charger & inverter.

Since I don't have a battery or the right voltage from the workbench
I would have to build another supply to make the measurements to see
what size inverter transformer I'll need. I want it as close as
possible to that actual requirement, to improve efficiency but not low
enough to starve the radio's plates.

[hifi-tek]

"Michael A. Terrell" <mike.t...@earthlink.net> wrote in message
news:vqWdnUkXhd49MJ3M...@earthlink.com...

Mike, I have a Motorola Ranger 700 with a 1R5 1T4 1U4 1DN5 and 3V4.
The idle current is about 12 ma, and at reasonable audio output, the current
rises to about 28 - 30 ma. on peaks. This should be about what your radio
would draw. I have used a 12.6 V CT filament transformer as an inverter
trans, and you can get about 120 volts with half wave rectification. I ran
it at 350 Hz to improve the efficency. A 8 ohm to 600 ohm transformer works
ok too. a simple regulator will put it at 90 volts.
Tom

[Michael A. Terrell]

Thank you. :)


I was hoping to use some of the PE-65728T 'Power over Ethernet'
transformers I have on hand. I have a full 13" reel of 850 of them. I
was thinking of 2 MHz, if they will work at that frequency to reduce
losses. There are three identical transformers per surface mount
package. Parallel the three primaries, series the secondaries & use a
tripler would give me about 85 volts.

Another idea was some of the Falco unshieled SMD power inductors. I
have a lifetime supply of them. (24, 13" reels) I bought a batch of
surplus surface mount parts really really cheap, including 300+ reels of
SMD resistors. Most are oddball values, but there is a decent assortment
for what I have in mind. This includes solid state, plug in replacements
for all of the tubes just to see how it performs. :)

Use one of the 2.2 uH Falco coil's existing winding, and wind a HV
secondary. A 9.6 volt battery with a single silicon ciode would put the
filaments int the safe range and a simple self excited Power FET
oscillator will make a small & efficient inverter that can be soldered
inside a metal shield. Add a PWM chip and a dozen more parts and it
will be regulated at 90 V, if needed.

[dave]

These methods will produce significant RFI without mitigation, no?

[philo]

On 01/24/2013 11:09 AM, dave wrote:

X

<snipped for brevity>

>
> These methods will produce significant RFI without mitigation, no?

Very good point. Considering the low current, a highly efficient power
supply is less important I'd think.


When building the supply though I'd err on the side of caution and rate
it at least double the expected current draw.


--
https://www.createspace.com/3707686

[nesesu]

On Wednesday, January 23, 2013 7:42:23 PM UTC-8, Michael Terrell wrote:
> Has anyone measured the current from the B battery section in a Z985 battery for a Transoceanic, or a Zenith 6G001/6C40 (Long Distance) which uses the following tubes: Type Plate current from data sheet 1-1LA6 0.55 mA 1-1LH4 ??????? 2-1LN5 1.60 mA 1-3Q5G/GT 8.50 mA This gives me 12.25 mA for four of the five tubes. The 1LH4 datasheets I have don't show any spec for plate current The Zenith 6G001/6C40 is on Riders Zenith page 15-30 and 15-31. I want to build a small inverter to run the radio off a rechargeable 9.6V NiMh battery after it's repaired. A drop in replacement for the original battery with a built in charger & inverter. Since I don't have a battery or the right voltage from the workbench I would have to build another supply to make the measurements to see what size inverter transformer I'll need. I want it as close as possible to that actual requirement, to improve efficiency but not low enough to starve the radio's plates.

I have found that all the 'transoceanic' type radios [Zenith, RCA, Hallicrafters, Silvertone] draw between 10 and 13 mA on 90V B+ under normal conditions [assuming they are recapped and working properly]. Operating the inverter at 2MHz is good for running the radio in the BC band, but could be a serious EMI source for any SW listening.
Personally, I have one of the inverter supplies I bought years ago that runs on, IIRC, 6 D cells and is already packaged in a cardboard box to fit in a TO style cabinet. I also made a battery pack that uses 60 C cells for the B+ and C cells for the A section and it fits the slightly smaller battery space of the Halli S-72 and the metal RCA portables.

Neil S.

[nesesu]

On Thursday, January 24, 2013 9:25:17 AM UTC-8, nesesu wrote:
> On Wednesday, January 23, 2013 7:42:23 PM UTC-8, Michael Terrell wrote: > Has anyone measured the current from the B battery section in a Z985 battery for a Transoceanic, or a Zenith 6G001/6C40 (Long Distance) which uses the following tubes: Type Plate current from data sheet 1-1LA6 0.55 mA 1-1LH4 ??????? 2-1LN5 1.60 mA 1-3Q5G/GT 8.50 mA This gives me 12.25 mA for four of the five tubes. The 1LH4 datasheets I have don't show any spec for plate current The Zenith 6G001/6C40 is on Riders Zenith page 15-30 and 15-31. I want to build a small inverter to run the radio off a rechargeable 9.6V NiMh battery after it's repaired. A drop in replacement for the original battery with a built in charger & inverter. Since I don't have a battery or the right voltage from the workbench I would have to build another supply to make the measurements to see what size inverter transformer I'll need. I want it as close as possible to that actual requirement, to improve efficiency but not low enough to starve the radio's plates. I have found that all the 'transoceanic' type radios [Zenith, RCA, Hallicrafters, Silvertone] draw between 10 and 13 mA on 90V B+ under normal conditions [assuming they are recapped and working properly]. Operating the inverter at 2MHz is good for running the radio in the BC band, but could be a serious EMI source for any SW listening. Personally, I have one of the inverter supplies I bought years ago that runs on, IIRC, 6 D cells and is already packaged in a cardboard box to fit in a TO style cabinet. I also made a battery pack that uses 60 C cells for the B+ and C cells for the A section and it fits the slightly smaller battery space of the Halli S-72 and the metal RCA portables. Neil S.

Oops, that should have been 60 AA cells for the B+

Neil S.

[Michael A. Terrell]

dave wrote:
>
> These methods will produce significant RFI without mitigation, no?

No. A properly designed switching supply will not radiate enough RF
to cause problems. A bunch of parts spread out and built point to point
will cause a lot of headaches. A faraday shield will reduce the
radiation to a point that you can't measure it without a lot of lab
grade test equipment. Even then, it can be at the noise floor and only
visible between the noise pulses from everything else. The AM broadcast
band is full of man made & natural noise.

I built my first high frequency inverting power supply 30 years ago.
It had a little radiation, but it was a haywire for proof of design. It
was wound on a torroid, and ran at the resonant frequency of the
material, to minimize loss & core heating. It was part of a 1 GHz home
brewed frequency counter with 10 sub mini VFD display tubes. Since it
was a prototype, I used a pair of pots between the base & the collector
of the other phase of the primary. That, with the series capacitor gave
me an adjustable R/C time constant. With an ammeter in series, I
adjusted each put for minimum current, with a fixed load. The efficiency
was over 90%

[Michael A. Terrell]

philo wrote:
>
> On 01/24/2013 11:09 AM, dave wrote:
>
> X
>
> <snipped for brevity>
>
> >
> > These methods will produce significant RFI without mitigation, no?
>
> Very good point. Considering the low current, a highly efficient power
> supply is less important I'd think.

Anyone can build a hodgepoge of junk and get something to work, but
if I'm going to put the time into it I want to build the best I can for
a reasonable price.

> When building the supply though I'd err on the side of caution and rate
> it at least double the expected current draw.

I was looking at a 50% excess capacity.

[Michael A. Terrell]

I was wondering how big a box it took for 60 C cells. Maybe an empty
Transoceanic case? ;-)

[Michael A. Terrell]

2 Mhz is easier to shield than a lower frequency. You guys seem to
forget that I worked with RF for decades, where every leak had to be
found & fixed. Why do you think they invented copper tape with
conductive glue & feedthrough caps? :-)

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

On Thu, 24 Jan 2013 09:09:26 -0800, dave <rick...@earthlink.net>
wrote:

An old friend of mine used to put 10 9 volt batteries in series
for his old portable radios. -or 13 9 volt nicads

[Michael Black]

On Thu, 24 Jan 2013, dave wrote:


> These methods will produce significant RFI without mitigation, no?
>

It's probably a tradeoff. A lower frequency ends up with a lot more junk,
because when multiplied you'd come across the harmonics a lot more
frequently. At 2MHz, the harmonics would come every 2MHz, only 15 of them
in the 1 to 30MHz range. Time was, virtually everyone had a crystal
calibrator that put out a signal every 100KHz (closer together for those
who got fancier), the difference was that it was stable, and you could
turn it off when you didn't need to calibrate.

And lower frequencies need bigger capacitors and inductors to filter out
the junk. It was easy to get .001uF feedthrough capacitors, but I don't
remember them being plentiful in .1uF (though that may just mean I didn't
need to look for larger values). The trick of a switching supply is to
shield it well, then make sure nothing gets in and out via the input and
output lines. If you can have it with no noise without any wires coming
out, you prbably can make it quiet. If the box is noisy, then any work on
the wires coming in and out won't do a thing, the noise will just work
around any work down on the output wires. Have a box that keeps the
signals in, and then you can do traditional things like a tuned circuit
between the output of the supply and where it leaves the box. That tuned
circuit would be much smaller (and easier) at 2MHz than at 100KHz or
wherever. This sort of thing isn't new, it's just under a different
guise. The old books used to dedicate plenty of space to eliminating
noise from alternators in cars, a switching supply isn't that different
noise-wise.

Michael

[philo]

On 01/24/2013 12:49 PM, Michael A. Terrell wrote:
>
> philo wrote:
>>
>> On 01/24/2013 11:09 AM, dave wrote:
>>
>> X
>>
>> <snipped for brevity>
>>
>>>
>>> These methods will produce significant RFI without mitigation, no?
>>
>> Very good point. Considering the low current, a highly efficient power
>> supply is less important I'd think.
>
>
> Anyone can build a hodgepoge of junk and get something to work, but
> if I'm going to put the time into it I want to build the best I can for
> a reasonable price.
>

Then you may be better off without going the high-frequency route,
You will have a lot less filtering to deal with.

Though "HF" design is prudent if you are handling a lot of power, the
amount of power you are talking about is quite small.

[Jim Mueller]

My RCA RC-25 tube manual says that the 1LH4 is electrically equivalent to
a 1H5. It then say that the plate current of a 1H5 with 90V on the plate
and 0V on the grid is 0.15mA. Since you need a plate resistor and
probably some bias too, the current in a receiver would be less.

It sounds like you are intending to power the filaments from a 9.6V
battery with a silicon diode in series. If you do that, you could sense
the voltage drop across the diode with a germanium transistor or a zero
bias FET and use that to switch the inverter on and off. Then you would
have a self-contained replacement battery with no modifications to the
radio required.

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

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

[Michael A. Terrell]

Thank you. My scans of those old tube manuals are packed away at the
moment. You saved nme from having to dig out the right box. :)

> It sounds like you are intending to power the filaments from a 9.6V
> battery with a silicon diode in series. If you do that, you could sense
> the voltage drop across the diode with a germanium transistor or a zero
> bias FET and use that to switch the inverter on and off. Then you would
> have a self-contained replacement battery with no modifications to the
> radio

Yes, I was planning on using a small power FET switch to control the
inverter. I was thinking of using a couple fake rivets to 'hold the
case togther' but they would be the connections to charge the battery
with no other visible difference. Of course, I would have to create a
custom label & name for the battery company. Maybe the 'Forever Battery
Co.' or 'Everlasting Battery Co.' ;-)

[Michael A. Terrell]

I want to get away from a laminated core transformer. The higher
frequency will reduce the inverter weight by 90%, and reduce the waste
heat. That will extend the life of the inverter. as well. The radio &
rechargable cells will be heavy enough without a half pound inverter.
The HF design will be closer to one ounce. :)

[philo]

On 01/24/2013 05:36 PM, Michael A. Terrell wrote:

>>>
>>
>> Then you may be better off without going the high-frequency route,
>> You will have a lot less filtering to deal with.
>>
>> Though "HF" design is prudent if you are handling a lot of power, the
>> amount of power you are talking about is quite small.
>
>
> I want to get away from a laminated core transformer. The higher
> frequency will reduce the inverter weight by 90%, and reduce the waste
> heat. That will extend the life of the inverter. as well. The radio &
> rechargable cells will be heavy enough without a half pound inverter.
> The HF design will be closer to one ounce. :)
>

I know how that goes.
I just retired from the industrial battery field and the industry is
going to "HF" battery chargers.

The large three phase units could have transformers that weighed 300
pounds. The "HF" version of an equivalent charger has a transformer so
small I can hold it in one hand!
--
https://www.createspace.com/3707686

[Michael A. Terrell]

Jim Mueller wrote:
>
> It sounds like you are intending to power the filaments from a 9.6V
> battery with a silicon diode in series. If you do that, you could sense
> the voltage drop across the diode with a germanium transistor or a zero
> bias FET and use that to switch the inverter on and off. Then you would
> have a self-contained replacement battery with no modifications to the
> radio required.

I would be able to use an opto isolator in series with the filaments,
if I raise the 9.6 volt pack to 10.8. The forward drop is in the 1.2 to
1.8 volt range, so it would be easy to dump that fraction of a volt.

Here is a typical, low cost unit:

<http://media.digikey.com/pdf/Data%20Sheets/Sharp%20PDFs/PC123%20Series.pdf>

The feedthrough caps have really gone up in price in the last 10
years. From a little over a buck, to almost 20. I wish I had bought a
whole lot more when they were a penny each at a surplus store back in
the '60s. :(

I want to try out the mini milling machine I bought last year, so I
may mill out a block of aluminum to hold the board, and heatsink the
FET.

[Michael A. Terrell]

philo wrote:
>
> On 01/24/2013 05:36 PM, Michael A. Terrell wrote:
>
> >>>
> >>
> >> Then you may be better off without going the high-frequency route,
> >> You will have a lot less filtering to deal with.
> >>
> >> Though "HF" design is prudent if you are handling a lot of power, the
> >> amount of power you are talking about is quite small.
> >
> >
> > I want to get away from a laminated core transformer. The higher
> > frequency will reduce the inverter weight by 90%, and reduce the waste
> > heat. That will extend the life of the inverter. as well. The radio &
> > rechargable cells will be heavy enough without a half pound inverter.
> > The HF design will be closer to one ounce. :)
> >
>
> I know how that goes.
> I just retired from the industrial battery field and the industry is
> going to "HF" battery chargers.

I hope it wasn't Yuasa, and for the 787. :(

> The large three phase units could have transformers that weighed 300
> pounds. The "HF" version of an equivalent charger has a transformer so
> small I can hold it in one hand!

A little bit more complex, but can be a lot cheaper & reliable.
Definitely not going to break your foot if you drop it.

I had an EE get bent all out of shape when he read some of the Sci-Fi
I was writing. They had a six phase power system, and he went ballistic.
I couldn't convince him that feeding six phase to six center tapped
power transformers would give him 12 phases and very low ripple DC from
a bank of 12 rectifiers, without huge filter caps. It's no wonder that
he was fixing VCRs out of a flea market. ;-)


> --
> https://www.createspace.com/3707686

[hifi-tek]

"Michael A. Terrell" <mike.t...@earthlink.net> wrote in message

news:luGdnXmpwI7dHpzM...@earthlink.com...

And don't forget phosphor bronze finger stock for the removeable panels!
Tom

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

Or the "Neverdead Battery Company" - with lightning bolts going OUT
of a white cat

[Carter]

On 1/24/2013 1:53 PM, Michael A. Terrell wrote:

> 2 Mhz is easier to shield than a lower frequency. You guys seem to
> forget that I worked with RF for decades, where every leak had to be
> found & fixed. Why do you think they invented copper tape with
> conductive glue & feedthrough caps? :-)

If you are building just one, no problem with the tape and caps, but if
you are building several for sale, it sounds a little labor intensive.

Also, FWIW, it's not necessarily the trivial case to tame the RFI. Every
time QST has done a review of switching power supplies, RFI across the
HF spectrum has been a major consideration.

In any event, it sounds like a fun project. Good luck and let us know
how it works out.

[Carter]

On 1/24/2013 12:28 PM, nesesu wrote:

>> I also made a battery pack that uses 60 C cells for the B+ and C
>> cells for the A section and it fits the slightly smaller battery
>> space of the Halli S-72 and the metal RCA portables. Neil S.

> Oops, that should have been 60 AA cells for the B+
>
> Neil S.

Any reason you didn't use (ten) 9 volt batteries for the B+? Presumably
cheaper and less space...

[Michael A. Terrell]

I still have about 30 feet in several sizes in a box, somewhere in
the damaged shop building. I bought it about 25 years ago.

[Michael A. Terrell]

Carter wrote:
>
> On 1/24/2013 1:53 PM, Michael A. Terrell wrote:
>
> > 2 Mhz is easier to shield than a lower frequency. You guys seem to
> > forget that I worked with RF for decades, where every leak had to be
> > found & fixed. Why do you think they invented copper tape with
> > conductive glue & feedthrough caps? :-)
>
> If you are building just one, no problem with the tape and caps, but if
> you are building several for sale, it sounds a little labor intensive.

The final costs will determine if I offer them for sale.

> Also, FWIW, it's not necessarily the trivial case to tame the RFI. Every
> time QST has done a review of switching power supplies, RFI across the
> HF spectrum has been a major consideration.

The switching supplies I've seen that were built for the Amateur
radio market were sloppy designs. Yes, they had aluminum shielding, but
only connected to the frame by four scress, into loose fitting PEM nuts.

I saw dozens of sloppy designs when Microdyne was looking for a new
supplier. Some were quiet with no load, then wiped out the IF in the
recievers we were testing them in. (70 MHZ & 300 MHz). some were noisy
all the time, and only one brand & model made it through the process.
The only issue we had with it was the way they routed the fan wires.

> In any event, it sounds like a fun project. Good luck and let us know
> how it works out.

Will do.

[Michael A. Terrell]

Longer lifetime between battery changes. :)

[Michael A. Terrell]

With burn marks in the carpet, like in 'National Lampoon's Christmas
Vacation'?


Motto: 'You'll never need another stinkin' battery!!!' ;-)

[Michael Black]

On Thu, 24 Jan 2013, Carter wrote:

> On 1/24/2013 1:53 PM, Michael A. Terrell wrote:
>
>> 2 Mhz is easier to shield than a lower frequency. You guys seem to
>> forget that I worked with RF for decades, where every leak had to be
>> found & fixed. Why do you think they invented copper tape with
>> conductive glue & feedthrough caps? :-)
>
> If you are building just one, no problem with the tape and caps, but if you
> are building several for sale, it sounds a little labor intensive.
>

Design is about overall results. Maybe it requires more effort, but maybe
it cuts things down in another area.

> Also, FWIW, it's not necessarily the trivial case to tame the RFI. Every time
> QST has done a review of switching power supplies, RFI across the HF spectrum
> has been a major consideration.
>

But they are lower in frequency, aren't they? A lot more harmonics, and
requring bigger filter coils to get the output clean.

I remember one review mentioned the switching supply could operate at 2
frequencies, which is an interesting thing. So if you are really bugged
by the signal, switch to the other frequency and hopefully it won't have a
harmonic on that frequency you are receiving. Actually kind of like those
"beat" switches on boomboxes and such, which are supposed to change the
bias oscillator in the tape deck in case a harmonic interferes with the
station you are listening to.

The reality is a lot of switching supplies don't really ahve much
shielding. In the early days when you'd start to see them in electronic
equipment, they'd be in their own shielding. Early VCRs that used them
had the power supply as a separate metal encased module, just like in
computers. But, look at more recent VCRs and the switching supply is
built on the main circuit board, the limits on radiated noise completely
depending on whether they really shield the plastic box of the vcr or not.

Or that LED desklamp I got at Ikea last year. It's great, I dumped a
bumch of halogen lamps for the LED lamps. But, the switching supply is
nice and small, and in a plastic box. I wouldn't expect it to be quiet
without any real shielding (and other switching AC adapters certainly seem
lacking in metal shielding).

In both cases, it's not that a lot of finicky work is needed, it's that
nobody bothered in the first place.

Michael

[Carter]

>> On 1/24/2013 12:28 PM, nesesu wrote:
>>
>>>> I also made a battery pack that uses 60 C cells for the B+ and C
>>>> cells for the A section and it fits the slightly smaller battery
>>>> space of the Halli S-72 and the metal RCA portables. Neil S.
>>
>>> Oops, that should have been 60 AA cells for the B+
>>>
>>> Neil S.

Carter wrote:

>> Any reason you didn't use (ten) 9 volt batteries for the B+? Presumably
>> cheaper and less space...

On 1/24/2013 11:34 PM, Michael A. Terrell wrote:

> Longer lifetime between battery changes. :)

Even when you account for the time it takes to solder 60 (!) cells
together? :-D

[William Sommerwerck]

> Oops, that should have been 60 AA cells for the B+.

Are you sure you don't mean AAA?

[philo]

On 01/24/2013 06:44 PM, Michael A. Terrell wrote:
>
> philo wrote:
>>
>> On 01/24/2013 05:36 PM, Michael A. Terrell wrote:
>>
>>>>>
>>>>
>>>> Then you may be better off without going the high-frequency route,
>>>> You will have a lot less filtering to deal with.
>>>>
>>>> Though "HF" design is prudent if you are handling a lot of power, the
>>>> amount of power you are talking about is quite small.
>>>
>>>
>>> I want to get away from a laminated core transformer. The higher
>>> frequency will reduce the inverter weight by 90%, and reduce the waste
>>> heat. That will extend the life of the inverter. as well. The radio &
>>> rechargable cells will be heavy enough without a half pound inverter.
>>> The HF design will be closer to one ounce. :)
>>>
>>
>> I know how that goes.
>> I just retired from the industrial battery field and the industry is
>> going to "HF" battery chargers.
>
>
> I hope it wasn't Yuasa, and for the 787. :(
>

I actually did work for Yuasa for five years but in the motive power and
stationary battery divisions. I am a lead-acid type of guy.

>
>> The large three phase units could have transformers that weighed 300
>> pounds. The "HF" version of an equivalent charger has a transformer so
>> small I can hold it in one hand!
>
>
> A little bit more complex, but can be a lot cheaper & reliable.
> Definitely not going to break your foot if you drop it.
>
> I had an EE get bent all out of shape when he read some of the Sci-Fi
> I was writing. They had a six phase power system, and he went ballistic.
> I couldn't convince him that feeding six phase to six center tapped
> power transformers would give him 12 phases and very low ripple DC from
> a bank of 12 rectifiers, without huge filter caps. It's no wonder that
> he was fixing VCRs out of a flea market. ;-)
>
>

That is absolutely great...as now that I am retired I am actually
reading through some of my Hawkins Electrical Guides ...copyright 1917.

The book not only covers three phase but six phase and even 12 phase
power distribution!

I do not have any photos from the book posted anywhere yet, other than
this mercury vapor rectifier:

https://sphotos-b.xx.fbcdn.net/hphotos-ash4/484667_566028606757846_1993531619_n.jpg


>> --
>> https://www.createspace.com/3707686


--
https://www.createspace.com/3707686

[Foxs Mercantile]

On 1/25/2013 9:23 AM, philo wrote:
>>
>
> That is absolutely great...as now that I am retired I am actually
> reading through some of my Hawkins Electrical Guides ...copyright 1917.

They are a fun read but ONLY for the various pictures
of stuff. That question and answer format is painful
at best.

[philo]

Considering that my book collection is close to 100 years old,
I would not expect it to be the best source for the latest in
technology...but seeing things at their roots gives a greater
understanding of how things came about.

I still find that I can learn things by reading an old text book.

--
https://www.createspace.com/3707686

[William Sommerwerck]

> I still find that I can learn things by reading an old text book.

There are classic texts that are classic because they explain things better
than newer texts.

[Michael A. Terrell]

I'd use cell holders. Six, ten cell holders & a few wires & you're
done.

[hifi-tek]

"Michael A. Terrell" <mike.t...@earthlink.net> wrote in message

news:g66dnaT4TZ54ZJ_M...@earthlink.com...

Yep, soldering on today's alkaline cells is not a good idea, it can damage
the cell and shorten its life. Holders are the way to go.
Tom

[Michael A. Terrell]

hifi-tek wrote:

>
> Michael A. Terrell wrote:
>>
>> I'd use cell holders. Six, ten cell holders & a few wires &
>> you're done.
>
> Yep, soldering on today's alkaline cells is not a good idea, it can
> damage the cell and shorten its life. Holders are the way to go.

I recently bought some decent six AA holders on Ebay. All in a
single layer to repair an old Sadelco SLM. The ones in the unit were
wrapped with multiple layers of electrical tape to hold them together.

[philo]

Those old books make good reading. I used to pick them up very cheaply
at a local used-book store until the owner finally caught on that they
were worth something.


OTOH: There is another store in town where the owner just does it as a
hobby and I literally have to force the guy to take more money that he
is asking. Sometimes I bring six books up to the counter and he'll just
say, "Five bucks" .

--
https://www.createspace.com/3707686

[Michael A. Terrell]

I found volume seven online, 44 MB file size:

<http://archive.org/download/hawkinselectrica000490mbp/hawkinselectrica000490mbp.pdf>

[.]

if you would look at the trade press, for example, Electronic Products
magazine, you would see lots of small highly efficient modular solutions

[Michael A. Terrell]

The holders I bought fit the avaiable space without modfiying the
equipment. I get daily e-mail from ECN and a half dozen distributors
about new and interesting items.

[Michael A. Terrell]

"Michael A. Terrell" wrote:
>

Can someone tell me how long the pins are in a Zenith Z985 battery?

From what I've seen online, they are 1/8" (.125") diameter. I need to
make some connectors, and I want to do it right. I am planning on using
brass rod, then turn it down to size & cut threads to anchor it in a
piece of 1/16" Phenolic board.

[nesesu]

On Friday, February 15, 2013 8:17:56 AM UTC-8, Michael Terrell wrote:
> "Michael A. Terrell" wrote: > Can someone tell me how long the pins are in a Zenith Z985 battery? From what I've seen online, they are 1/8" (.125") diameter. I need to make some connectors, and I want to do it right. I am planning on using brass rod, then turn it down to size & cut threads to anchor it in a piece of 1/16" Phenolic board.

Michael, pins 3/8 to 1/2" long should be fine for a plug. You can also salvage the 1/8" nickel plated pins from a dud 'large pin' tube base. If you break away the bakelite [or hard rubber] base shell from the pins, you can fairly easily roll the original staking down and re-stake them into the new phenolic plug disk. IIRC, the pin spacing is tight enough on those connectors that the nuts will be mightly close together.

Neil S.

[Michael A. Terrell]

I don't have any donor tubes on hand, and I was looking at making a
batch to sell. I found a thousand new pins for sale, but they are .085"
:(

I was thinking of threading the phenolic and screwing the pins into
it, leaving a stud to solder to on the inside. There are some very thin
PEM nuts available that may be possible to press into the back side. If
so, once they have wires soldered to them they won't be easy to remove.
A small shoulder on the front side would help keep t from digging into
the phenolic. They would have to be turn, one at a time which would be
a pain. There just isn't enough volume to have someone CNC them. They
were a lot of dead links from people who had sold custom connectors. A
lot of what I saw was crap. This is to be for a rechargeable battery
pack, so I want them to be decent quality. I was looking at solid 6 AWG
hard drawn copper ground wire for the pins. Machine them, and either
tin plate, or dip them into my 650 W solder pot.

I found some small torroids that should handle 4-6 VA, so both the B+
and the filament could be regulated with little loss.

I'm still kicking ideas around. :)

[Jiri Placek]

On Wednesday, January 23, 2013 10:42:23 PM UTC-5, Michael Terrell wrote:

> I want to build a small inverter to run the radio off a rechargeable
> 9.6V NiMh battery after it's repaired. A drop in replacement for the
> original battery with a built in charger & inverter.

Check this:
http://www.dos4ever.com/battery/battery.html

Jiri Placek
Boyertown, PA