Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 1806927 times)

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Online beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38900 on: September 15, 2019, 01:08:01 am »
Does anyone know what I might use an HP 6177C current source for? Looks like 500mA with 50V compliance. There’s a rather nice looking one on eBay. I can’t think of a use now for one off the top of my head but I will probably find a use for one in the future and regret not buying it if I do.

Characterizing components would be one use. Let the voltage run free and lock the current to X. Inject X mA into a Transistor, LED etc then measure voltage gain......
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Offline Neomys Sapiens

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38901 on: September 15, 2019, 02:06:02 am »
Does anyone know what I might use an HP 6177C current source for? Looks like 500mA with 50V compliance. There’s a rather nice looking one on eBay. I can’t think of a use now for one off the top of my head but I will probably find a use for one in the future and regret not buying it if I do.
I hope you have more luck than I with the 6177B. The changes from the original version are of such a magnitude that I find it irresponsible of HP that no updates of (for example) the location diagrams/PCb views were made. Also, the fault-finding procedure involves a lot of soldering.
Other that that, I would like to have one, if it did work.
 

Offline Neomys Sapiens

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38902 on: September 15, 2019, 02:07:42 am »
Is anyone of the regulars in urgent need of Tek ground leads with the tubular connector (such as used with the P6122, P6131)?
 

Offline wch

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38903 on: September 15, 2019, 02:15:50 am »
Is anyone of the regulars in urgent need of Tek ground leads with the tubular connector (such as used with the P6122, P6131)?

Yes, actually. I could use four of them...
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Offline Brumby

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38904 on: September 15, 2019, 02:25:49 am »
I made a new avatar based on yesterday's discussion  :-DD

Source artwork:

https://imgur.com/a/Rc4ABPv

Here's my thought on the subject...

 
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Offline VK5RC

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38905 on: September 15, 2019, 02:46:54 am »

A long and sorry saga, how hard can it be to fix a 12MHz counter with discrete 7 series logic ?



Isn't it a factor that older equipment often fails in quite creative ways, with some components aging more gracefully than others...  transistors that nearly have enough gain,  resistors that almost have the right resistance,  capacitors that almost have the right value, IC gates that get so close to pulling its line up high enough,  a power supply that is almost quiet enough,  decoupling components that are almost good enough, that kind of thing...   
That is so true here, the old transistor had a hFE of  10 or so, I think the 7400 was also loading too much as well.
I think you learn so much when repairing, not only about electronics but also perseverance and how not to hit people or things.
Whoah! Watch where that landed we might need it later.
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38906 on: September 15, 2019, 02:58:19 am »
Fuck it. I forgot to bid on these earlier  :palm:



I had the hp on top, lots of gold traces in that one. Would like to obtain a nixie unit too when I can.  :popcorn:
Oh, I have a almost mint 3478A complete lead acid battery and I love it. To borrow a phrase from med, it's dead nuts too. It's so handy as I can use without having to power up the stack[emoji16]

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Online 0culus

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Online Gandalf_Sr

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38908 on: September 15, 2019, 11:32:56 am »
OK, I've been in denial and have not been to my TEAA meetings as often as a should have but my 'MALFUNCTION!'ing Druck Unomat TRX is proving to be a bit of a pig to get working, does ANYONE have a schematic or service manual for this or is it, as I suspect, kept in a secret vault on the dark side of the moon?

I found this gem today which I'll share...

I'd like to make the world a better place but they won't give me the source code.
I'd like to make the world a better place but they won't give me the source code
 

Online med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38909 on: September 15, 2019, 12:02:07 pm »
If you find that secret vault please let me know because I have no idea what a "Druck Unomat TRX" is supposed to be or look like. Perhaps a pix or two so if I happen to trip over one I'll know what it is.  :-// But right now all I can give you is a dumb deer in the headlights look.  :palm: :-DD
An old gray beard with an attitude.
 

Online Gandalf_Sr

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38910 on: September 15, 2019, 12:18:35 pm »
If you find that secret vault please let me know because I have no idea what a "Druck Unomat TRX" is supposed to be or look like. Perhaps a pix or two so if I happen to trip over one I'll know what it is.  :-// But right now all I can give you is a dumb deer in the headlights look.  :palm: :-DD
Have you heard of Google?  :palm:
I'd like to make the world a better place but they won't give me the source code
 

Online med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38911 on: September 15, 2019, 12:39:35 pm »
If you find that secret vault please let me know because I have no idea what a "Druck Unomat TRX" is supposed to be or look like. Perhaps a pix or two so if I happen to trip over one I'll know what it is.  :-// But right now all I can give you is a dumb deer in the headlights look.  :palm: :-DD
Have you heard of Google?  :palm:

Google? What's that? Is it like the "Yahoo" I've been using? I guess I should try it out.  :-+ Or better still drink my morning coffee first before posting so I'm fully awake.  |O

Looks like a neat little device and quite frankly have never heard of it. But since I can't help I'll quit clogging up the airwaves and hopefully someone knows of a source of documentation.
An old gray beard with an attitude.
 

Online Kosmic

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38912 on: September 15, 2019, 03:17:28 pm »
I was looking for a new handheld multimeter. Was initially thinking of buying a Fluke 87 Since I wanted better accuracy and digits.

But since the Fluke 87 are still pretty expensive, I ended up finding a way better deal with a HP 974a. I didn't really know about those meter and found it on ebay by accident. Specs are pretty good (4.5 digits, 50000 counts, 0.05% accuracy) and it's in pretty good shape. The unit I have was calibrated in 2018 and is due in 2021. I'm pretty happy with my purchase.







« Last Edit: September 15, 2019, 03:20:50 pm by Kosmic »
 
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Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38913 on: September 15, 2019, 03:58:14 pm »
I found this gem today which I'll share...

I'd like to make the world a better place but they won't give me the source code.

It is being reverse engineered as we speak.

And we (Venter actually!) are adding new syntax to the language :)
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38914 on: September 15, 2019, 04:12:31 pm »
@tggzzz - And no doubt, all your maths will be RPN...  :-DD

@Kosmic - Neat find on that 974A... I especially like the "dumbass-resistant" current jacks...   ;)

Oh, I have a almost mint 3478A complete lead acid battery and I love it. To borrow a phrase from med, it's dead nuts too. It's so handy as I can use without having to power up the stack[emoji16]

Interesting... I vaguely remember you mentioning this before, and considered adding a Li-Ion pack "option" to mine out of curiosity about the theoretical lower noise floor of battery-powered gear. Any real-world evidence in your case to support that theory?  >:D

mnem
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« Last Edit: September 15, 2019, 04:16:18 pm by mnementh »
 

Online Kosmic

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38915 on: September 15, 2019, 04:32:45 pm »
@Kosmic - Neat find on that 974A... I especially like the "dumbass-resistant" current jacks...   ;)

Pretty error proof. You can only open the amp shutter in amp mode  :)
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38916 on: September 15, 2019, 04:43:21 pm »
You should know better than to throw down the gauntlet like that... especially IN HERE...  :-DD

mnem
"It's impossible to make anything foolproof; fools are too damned inventive." ~ grand-dad
 
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Online med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38917 on: September 15, 2019, 05:02:08 pm »
The 465B/DM44 is back together. Powered up first try no issues. The +55V reference is sitting at +55.04V which is perfect. No adjustment required. All supply voltages in spec. And best of all, no ripple on the traces. Nice and sharp. But there's still an issue. There's an identical roll-off on both channels as seen here. I didn't think replacing the PSU caps would fix this and that proved to be correct. The issue is not the attenuators, the B/W limit switch, nor the pre-amp board (It's been changed). So the prime suspect is the Vertical Output board. I do have a spare board and I could just change it out but I'd rather try to identify and fix the issue. So this will be an excellent opportunity to put the 485 to work. Which BTW has been on the torture rack for the past week and a half and running perfectly with no issues. So stay tuned, obviously I'll post what I find.

An old gray beard with an attitude.
 
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Online PA0PBZ

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38918 on: September 15, 2019, 05:06:23 pm »
I ended up finding a way better deal with a HP 974a.

Oh dear, is it RPN?
Keyboard error: Press F1 to continue.
 

Online Kosmic

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38919 on: September 15, 2019, 05:22:45 pm »
I ended up finding a way better deal with a HP 974a.

Oh dear, is it RPN?

No, unfortunately since the device mostly measure and doesn't do much calculation. (It's a multimeter  ;))
 

Online PA0PBZ

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38920 on: September 15, 2019, 05:43:02 pm »
I ended up finding a way better deal with a HP 974a.

Oh dear, is it RPN?

No, unfortunately since the device mostly measure and doesn't do much calculation. (It's a multimeter  ;))

You are no fun  :P >:D
Keyboard error: Press F1 to continue.
 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38921 on: September 15, 2019, 06:27:35 pm »
The 465B/DM44 is back together. Powered up first try no issues. The +55V reference is sitting at +55.04V which is perfect. No adjustment required. All supply voltages in spec. And best of all, no ripple on the traces. Nice and sharp. But there's still an issue. There's an identical roll-off on both channels as seen here. I didn't think replacing the PSU caps would fix this and that proved to be correct. The issue is not the attenuators, the B/W limit switch, nor the pre-amp board (It's been changed). So the prime suspect is the Vertical Output board. I do have a spare board and I could just change it out but I'd rather try to identify and fix the issue. So this will be an excellent opportunity to put the 485 to work. Which BTW has been on the torture rack for the past week and a half and running perfectly with no issues. So stay tuned, obviously I'll post what I find.



You could test that hypothesis by connecting the output on the rear panel to another scope. If that looks OK the the vert CRT driving board is the problem. Are there tweaks on it?
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline mansaxel

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38922 on: September 15, 2019, 06:39:01 pm »
[Oh, I have a almost mint 3478A complete lead acid battery and I love it. To borrow a phrase from med, it's dead nuts too. It's so handy as I can use without having to power up the stack[emoji16]

I have the 3438A, and I love it! Quite accurate, to my (non-volt-nut) standards, at least.

Having more multimeters always is a big win.

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38923 on: September 15, 2019, 06:48:22 pm »
Yeah, the 3478A is as "volt-nut" as this tinkerdwagon is ever gonna get in this lifetime...  :P

mnem
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Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #38924 on: September 15, 2019, 06:51:47 pm »
You pack like ebay GSP  :-DD
 


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