Test Equipment Anonymous (TEA) group therapy thread

[Neomys Sapiens]

Is anyone of the regulars in urgent need of Tek ground leads with the tubular connector (such as used with the P6122, P6131)?

[worsthorse]

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...

[Brumby]

I made a new avatar based on yesterday's discussion 

Source artwork:

https://imgur.com/a/Rc4ABPv

Here's my thought on the subject...

[VK5RC]

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.

[Specmaster]

Fuck it. I forgot to bid on these earlier 

I had the hp on top, lots of gold traces in that one. Would like to obtain a nixie unit too when I can. 

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]

Sent from my POT-LX1 using Tapatalk

[0culus]

Note to self: read the damn datasheet more carefully BEFORE soldering next time.   

[Gandalf_Sr]

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.

[med6753]

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. 

[Gandalf_Sr]

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. 

Have you heard of Google? 

[med6753]

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. 

Have you heard of Google? 

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. 

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.

[Kosmic]

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.

[tggzzz]

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

[mnementh]

@tggzzz - And no doubt, all your maths will be RPN... 

@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? 

mnem
*currently packing my 3DPrinter away for long-term storage*

[Kosmic]

@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 

[mnementh]

You should know better than to throw down the gauntlet like that... especially IN HERE... 

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

[med6753]

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.

[PA0PBZ]

I ended up finding a way better deal with a HP 974a.

Oh dear, is it RPN?

[Kosmic]

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  )

[PA0PBZ]

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 

[tggzzz]

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?

[mansaxel]

[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.

[mnementh]

Yeah, the 3478A is as "volt-nut" as this tinkerdwagon is ever gonna get in this lifetime... 

mnem
*back out into the suck*

[bd139]

You pack like ebay GSP 

[GreyWoolfe]

I had the hp on top, lots of gold traces in that one. Would like to obtain a nixie unit too when I can. 

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]
[/quote]

I have 2 myself of these also and paid less than $100 US for each one of them.  Very nice meters.

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.

I just searched evilBay for one and all that comes back are magenta pagewide ink cartridges 

[bd139]

Fucks sake. My T440 just blew up. Looks like the mains adapter had a blow out and took the laptop with it. Gahhhhh bastard!