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Re: 6C10 Tube

 

The 6AC10 has an amplification factor of 62 for each section (like a 12AT7). The 6C10 is 100, as you pointed out, like a 12AX7.

They work perfectly in a Heath HO-10, probably in other instruments, and are around $7 instead of $100 to $200 (ridiculous)...
-Charles
WTB: 453 rear cover plate

 

I recently got a 453 that needed some work to get going but it’s missing the rear cover plate. It’s an early one that has a separate power cord. If anyone has a parts unit that would let just the rear cover go please pm me.
Re: Experiences / Improvements with 1L5

 

You could also upload them to TekWiki at .

Regards,
Dave Wise
________________________________
From: [email protected] <[email protected]> on behalf of Karl Goedecke <karl@...>
Sent: Sunday, May 5, 2024 2:56 PM
To: [email protected] <[email protected]>; [email protected] <[email protected]>
Subject: Re: [TekScopes] Experiences / Improvements with 1L5

Hi Benedikt,

I've scanned about 10 pages of pencilled schematics and notes about the 1L5 modifications. I'm trying to make them useable and add schematic refs.

I still want to do some explanations as well.

Can you email me so I can get your email? I can't use the Tekscopes link; it's in Outlook, which I don't have.

Karl G
Re: Dennis Tillman Tek 575 Curve Tracer Adapter PCB?

 

I hope so too, I have a 575 that I want to set up as a dedicated tube tester. I’ve been watching this thread with great interest.

Haven’t found a decent 576 that’s affordable yet.
Re: Keithley anyone?

 

It took me a very long time to find an original manual and probe for my 610B electrometer.

I was thinking of starting a Keithley group but it's hard to gauge how much interest there would be.

DaveD
KC0WJN

On May 5, 2024, at 18:51, jspencerg via groups.io <jspencerg@...> wrote:

?Yes, I'm surprised about the lack of traffic on forums and YT about the old keithleys. I have working 2000 dmm, 236, and 610C units. I am getting into the fix with a 619. I was lucky to get a printed manual for the 619. I intend to have another go with my 228 after further honing of my chops.
Re: Keithley anyone?

 

Yes, I'm surprised about the lack of traffic on forums and YT about the old keithleys. I have working 2000 dmm, 236, and 610C units. I am getting into the fix with a 619. I was lucky to get a printed manual for the 619. I intend to have another go with my 228 after further honing of my chops.
Re: [OT] Shocks in a large market. How to check ESD direction?

 

It is easy to make an electroscope. Walk around store with your finger on the electrode and observe when you get charged. Wear a foil hat if you don't want to answer any questions.
Re: Experiences / Improvements with 1L5

 

Hi Benedikt,

I've scanned about 10 pages of pencilled schematics and notes about the 1L5 modifications. I'm trying to make them useable and add schematic refs.

I still want to do some explanations as well.

Can you email me so I can get your email? I can't use the Tekscopes link; it's in Outlook, which I don't have.

Karl G
Re: 6C10 Tube

 

6C10s are three 12AX7 sections in one envelope. For many applications, the 6AC10 will work fine, it's three 12AU7 sections in one envelope. Not only do the AudioPhools like them, guitar amplifier builders are smitten too, and many hifi amplifiers and tuners use them. Compactrons were a last ditch effort to reduce vacuum tube overall cost and size, and buy time for developing solid state equipment. For this reason, they tend to be more rugged and longer lasting so people won't be? so annoyed at replacing them when only one section has failed.

?? Bruce Gentry, KA2IVY

On 5/4/24 16:11, Tom Lee wrote:
Thank you, Dave. I’m wondering whether that 6C10 was used in a production instrument or an in-house fixture. I just checked the web and it commands crazy prices on eBay. Audiophiles have clearly fallen in love with its triple-triode sonic magic.

Tom


Sent from an iThing; please forgive the typos and brevity

On May 4, 2024, at 12:58, Dave Wise <d44617665@...> wrote:

?I don't know which scope used compactrons. I do know a cal fixture sort of did.
From my notes:

Tektronix 067-0502-01 Amplitude Calibrator.

The voltage regulator originally used the 6GE8/7734
signal pentode/power triode, but later switched to the 6G11
signal pentode/beam power tube, triode-connected in a purpose-built adaptor.

Besides the 12BU pinout (6AL11 and 6G11) the adaptor is made for,
the 12EZ tubes (6AD10 6BF11 6BY11 6T10) can probably work,
with a new adaptor.

Dave Wise
________________________________
From: [email protected] <[email protected]> on behalf of Tom Lee <tomlee@...>
Sent: Saturday, May 4, 2024 12:24 PM
To: [email protected] <[email protected]>
Subject: Re: [TekScopes] 6C10 Tube

I’m curious: which Tek scope used compactrons?

Cheers
Tom
Sent from an iThing; please forgive the typos and brevity

On May 4, 2024, at 11:23, Bill Riches via groups.io <bill.riches@...> wrote:

?Help! I am looking for a 6C10 tube.
73,
Bill, WA2DVUCape May, NJ
Re: Dennis Tillman Tek 575 Curve Tracer Adapter PCB?

 

Dennis used to sell these from his table at the Ham swaps. Hopefully he will be attending them again soon.
Re: Keithley anyone?

 

I have 610B; we used those to measure the triboelectric charges on toner way back when laser printers were in vogue.

I am surprised to find that there is no Keithley groups.io group.

DaveD
KC0WJN

On May 5, 2024, at 08:34, Joel Setton via groups.io <setton@...> wrote:

?Hi,

I also have a few Keithley instruments :
- one 480 Picoammeter, works great
- One 616 digital electrometer which was "flaky" when I got it. I have since replaced the dual FET (Q301 A/B) in the Autoranging Amplifier. I also installed a standard BNC with an isolated mount to replace the input Triax connector, which was missing when I bought the unit.
I replaced the op-amp on the input board with an LM308. The original chip was the source of low-level AC oscillations, which resulted in unstable readings.
I also designed a small board with a 68HC11 which plugs into the QA408 socket, which normally carries the LSI-2 chip on the logic board. This was done as a protection against a potential failure of the original SL35155 chip, which is pure unobtainum.
Now the 616 is future-proof and it works great !
I even sold a few of these replacements boards for the SL35155 on a popular auction site. If anyone is interested, just drop me a PM.
- I also have a 261 Picoampere source, which was the cause of countless headaches because of erratic drift. At first I thought it just needed to be calibrated, but weekly recalibration is not what you expect to do ! Finally, I found that the 200-ohm calibration potentiometers were prone to random changes in cursor resistance, and since cursor current is several milliamps, this resulted in degraded accuracy. I couldn't find any replacements for the pots, and concluded that the design of the power regulator with these potentiometers was inherently flawed. One day I decided to bite the bullet and I designed a new regulator board, using good cermet trimpots in a scheme where the cursor current is close to zero. This performed exactly as expected, and I have not seen any significant drift in output current ever since.
If anyone is interested in the new regulator design, I have schematics and a few blank PCBs available.

That's all !
Cheers,
Joel
Re: [OT] Shocks in a large market. How to check ESD direction?

 

On Sun, May 5, 2024 at 05:01 AM, cheater cheater wrote:

anyways, does anyone know how to measure the direction of esd? some sort of galvanometer?
Gold leaf electrometer

--
Jim Adney
Madison, WI USA
Re: 6C10 Tube

 

On Sat, May 4, 2024 at 05:16 PM, Morris Odell wrote:

The 556 is the only one I've experience of but I can't remember which tube it uses.
From TekWiki: The 6M11, a pentode/dual triode, used only in the 556

--
Jim Adney
Madison, WI USA
Re: [OT] Shocks in a large market. How to check ESD direction?

 

On Sat, May 4, 2024 at 05:22 PM, cheater cheater wrote:

what would make an "accidental" ion generator?
Only one I can think of offhand would be an electrostatic air cleaner. These are often set up as part of an HVAC system, for people with pollen allergy problems. And neon sign transformers. I'm sure there are others. Old TV sets could do it, but those were very localized.

--
Jim Adney
Madison, WI USA
Re: [OT] Shocks in a large market. How to check ESD direction?

 

My understanding of the “air sanitizers” is that there are at least two
types. One uses ultraviolet light. Shortwave UV (UV-C) will work to destroy
bacteria and viruses in the air, but some have the problem of generating
ozone. If they use a UV band at a certain range of wavelengths. the UV is
still antimicrobial but does not generate ozone. According to the vendors
of these systems, certain wavelengths will actually break down ozone. A
side effect of these is generating ions. Hospitals use UV light air
sanitizers in operating rooms. It would be very dangerous to allow static
charges to build up because of ions - sparks can ignite flammable
anesthetics. OR flooring is usually conductive for this reason.

Another system is an ion generator. You may have seen the “after a
rainstorm fresh air” stuff (though I think it needs lightning during a
storm for this). Because of problems with charged ions in the air (maybe
causing shocks?) there are bipolar ion generators.

Then there are the “loss control” systems - meaning anti-theft systems.
These use RF, but are generally localized to the store exits and I’ve not
seen them in supermarkets. These use those anti-theft tags on clothing and
stuck onto boxes. The RF fields are relatively limited to the area around
the exits.

The Amazon markets that have the system that lets you simply put things in
your shopping cart and then when you’re done just walk out - it’s called
“Just Walk Out”. My understanding of that system is that it uses multiple
video cameras, weight sensors, and an AI application that recognizes
products (and likely the shopper as well, but I think it may use an app on
your smartphone for that). But it does not use RF tags so far as I know and
no generalized RF fields as part of the system.

Shopping cart wheels may have, or are being, modified because some markets
have changed to anti-theft carts. Loss of shopping carts can be expensive,
so there are some available with a mechanism in the wheels and some sort of
sensor buried in the parking lot entrances/exits that will cause the wheels
to lock up if you try to leave the parking area with the cart.

I think static buildup is the likely cause. You could try taking a length
of metal chain, toss it in the lower part of the shopping cart and let one
end drag on the floor.

Steve H.

On Sun, May 5, 2024 at 03:52 Jim Ford via groups.io <james.ford=
[email protected]> wrote:

Well, we have used ionizers at work to decrease the risk of ESD, so maybe
they would have the opposite effect, 搁别苍é别? Jim Ford

Yahoo Mail: Search, Organize, Conquer

On Sat, May 4, 2024 at 11:06 PM, 搁别苍é别<k6fsb.1@...> wrote: I
wonder if the companies installed an ion generator to purify the "air"
due to the covid stuff?
...just thought.....
搁别苍é别

On 5/4/24 9:53 PM, Frank DuVal via groups.io wrote:
Same here, at the close by Walmart. If I hold the handle so I touch
the metal I do not get the shocks. But let a gap form and Whammo! But
not always, so cart differences, humidity differences?

Frank DuVal

On 5/4/2024 9:49 PM, Dave Casey wrote:
I too have dealt with shocks from the cart at my grocery store. I
attributed it to the cart building up charge by rolling. A good test
might
be to hang a dragging chain from the cart, but I've never bothered.

Dave Casey
Re: Keithley anyone?

 

Hi,

I also have a few Keithley instruments :
- one 480 Picoammeter, works great
- One 616 digital electrometer which was "flaky" when I got it. I have since replaced the dual FET (Q301 A/B) in the Autoranging Amplifier. I also installed a standard BNC with an isolated mount to replace the input Triax connector, which was missing when I bought the unit.
I replaced the op-amp on the input board with an LM308. The original chip was the source of low-level AC oscillations, which resulted in unstable readings.
I also designed a small board with a 68HC11 which plugs into the QA408 socket, which normally carries the LSI-2 chip on the logic board. This was done as a protection against a potential failure of the original SL35155 chip, which is pure unobtainum.
Now the 616 is future-proof and it works great !
I even sold a few of these replacements boards for the SL35155 on a popular auction site. If anyone is interested, just drop me a PM.
- I also have a 261 Picoampere source, which was the cause of countless headaches because of erratic drift. At first I thought it just needed to be calibrated, but weekly recalibration is not what you expect to do ! Finally, I found that the 200-ohm calibration potentiometers were prone to random changes in cursor resistance, and since cursor current is several milliamps, this resulted in degraded accuracy. I couldn't find any replacements for the pots, and concluded that the design of the power regulator with these potentiometers was inherently flawed. One day I decided to bite the bullet and I designed a new regulator board, using good cermet trimpots in a scheme where the cursor current is close to zero. This performed exactly as expected, and I have not seen any significant drift in output current ever since.
If anyone is interested in the new regulator design, I have schematics and a few blank PCBs available.

That's all !
Cheers,
Joel
Re: [OT] Shocks in a large market. How to check ESD direction?

 

rubber wheels here, by the looks of it the carts are at least 10 years
old. so no, not polyurethane and not new.

anyways, does anyone know how to measure the direction of esd? some
sort of galvanometer?

On Sun, May 5, 2024 at 5:05?AM greenboxmaven via groups.io
<ka2ivy@...> wrote:

I think the problem comes from shopping carts with plastic tires instead
of rubber. I had a small spark at a supermarket that had replaced their
carts a few weeks earlier. The wheels have bright red polyurethane?
tires. The problem will likely go away once the wheels get some dirt and
scratches on them.

Bruce Gentry, KA2IVY

On 5/4/24 21:49, Dave Casey wrote:
I too have dealt with shocks from the cart at my grocery store. I
attributed it to the cart building up charge by rolling. A good test might
be to hang a dragging chain from the cart, but I've never bothered.

Dave Casey

On Sat, May 4, 2024, 7:09 PM Dave Seiter via groups.io <d.seiter=
[email protected]> wrote:

Interesting; last week I was at one of the Costcos I visit frequently,
and I had the same experience (which has NEVER happened before, and I've
been shopping there since the mid 80's). The charge would build up very
quickly (maybe 6-8 steps), then discharge between my hands/fingers and the
plastic grip of the cart. Most of the time it discharged while I was
gripping it, not when I let go and re-grasped it. It seemed like it was
building up a charge until it could overcome cracks in the plastic or ???.
No discharges onto other metal surfaces. Same old shoes/jeans etc.
Outside the store in the parking lot everything was normal.
-Dave
On Saturday, May 4, 2024 at 09:31:40 AM PDT, cheater cheater <
cheater00social@...> wrote:

Hi all,
I frequent a large grocery market nearby and inevitably every time I
go there I get electrical shocks. I walk around with a cart and often
if I touch a metal fixture (fridge, mesh rack) I get a painful shock.
Sometimes I get a shock if I leave the cart for a few seconds and then
touch its metal mesh.

I was wondering what everyone thought. At first I thought it would be
ESD, but why would it be so extreme? It happens every time. I live in
a place that's pretty dry - RH goes under 20% regularly - and being on
a plain it has a lot of wind, which could create triboelectric
charging. But I'm not really sure about this.

I don't know which way the ESD happens. Is my body discharging into
the cart? Is the cart discharging into my body? Is my body discharging
into the racks or vice versa? How can one check the directionality of
ESD?

One theory about ESD I have is that the fixtures get charged and my
body gets the charge applied to it. This however isn't necessarily
true to me because eg today I got a painful shock from touching the
inside metal surface of a fridge, and that's supposed to be earthed.

Another theory is that as I walk around in the store, as I move around
with the cart, that charges my body. I wear rubber sandals and the
cart has rubber wheels. That would mean I'm a conductor, attached to a
large antenna (the cart's mesh frame), moving through dry air,
insulated from the ground. The ground is made out of some sort of high
impact ceramic-ish tile. But then why would my own cart shock me just
mere seconds after letting go of it? I was unloading my groceries for
the cashier.

My third theory is that this whole facility has a lifted earth
potential. There's an industrial area nearby and they may be dumping a
lot of current into earth which would create a situation where walking
on the ground charges you, and then touching something that's low-Z to
neutral discharges your body (in this case this would be the earthed
fridges etc).

I was wondering how people would approach diagnosing this problem, and
how you would fix it if you had the ability to change anything about
the facility at hand - more as a thought exercise, but if I figure out
what's going on I'm going to write to the company.

Thanks
Re: [OT] Shocks in a large market. How to check ESD direction?

 

Well, we have used ionizers at work to decrease the risk of ESD, so maybe they would have the opposite effect, 搁别苍é别?? ? ? ? ? ? Jim Ford?

Yahoo Mail: Search, Organize, Conquer

On Sat, May 4, 2024 at 11:06 PM, 搁别苍é别<k6fsb.1@...> wrote: I wonder if the companies installed an ion generator to purify the "air"
due to the covid stuff?
...just? thought.....
搁别苍é别

On 5/4/24 9:53 PM, Frank DuVal via groups.io wrote:
Same here, at the close by Walmart. If I hold the handle so I touch
the metal I do not get the shocks. But let a gap form and Whammo! But
not always, so cart differences, humidity differences?

Frank DuVal

On 5/4/2024 9:49 PM, Dave Casey wrote:
I too have dealt with shocks from the cart at my grocery store. I
attributed it to the cart building up charge by rolling. A good test
might
be to hang a dragging chain from the cart, but I've never bothered.

Dave Casey
Re: [OT] Shocks in a large market. How to check ESD direction?

 

I wonder if the companies installed an ion generator to purify the "air" due to the covid stuff?
...just? thought.....
搁别苍é别

On 5/4/24 9:53 PM, Frank DuVal via groups.io wrote:
Same here, at the close by Walmart. If I hold the handle so I touch the metal I do not get the shocks. But let a gap form and Whammo! But not always, so cart differences, humidity differences?

Frank DuVal

On 5/4/2024 9:49 PM, Dave Casey wrote:
I too have dealt with shocks from the cart at my grocery store. I
attributed it to the cart building up charge by rolling. A good test might
be to hang a dragging chain from the cart, but I've never bothered.

Dave Casey
Re: [OT] Shocks in a large market. How to check ESD direction?

 

Same here, at the close by Walmart. If I hold the handle so I touch the metal I do not get the shocks. But let a gap form and Whammo! But not always, so cart differences, humidity differences?

Frank DuVal

On 5/4/2024 9:49 PM, Dave Casey wrote:
I too have dealt with shocks from the cart at my grocery store. I
attributed it to the cart building up charge by rolling. A good test might
be to hang a dragging chain from the cart, but I've never bothered.

Dave Casey
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