Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

Okies.... I think the drift measurement thesis makes most sense. Neat! I learned something today!

Since here are some folks which are interested in valves, tubes, vacuum tubes or electron tubes, perhaps this may be of some interest.

There is a guy in Germany, Helmut Weigl, he developed a digitally tube tester, the so-called RoeTest. If you are looking for a nice project, this could be one for a tube enthusiast. I have no affiliation to him besides I'm finding this a very interesting project. I have considered to build one by myself. This is his website: http://www.roehrentest.de/EnglishInfo.html

(SNIP)   Really, we are not the only crazy TEA folks here on earth.       

Mmmmoklay... since I'm not that well-versed in hollow-state, and what I could glean from the site didn't make it clear to me... The reason this thing needs so much heat-sink is because it's supposed to do full-load testing for matching tubes electron valves...?

Still, gorgeous bit of gear, no matter what they do, or how. 

mnem
*scrubbing a gas range*

[med6753]

Tggzzz, if you get a chance to open up your 485 this week these are the parameters you should set up on yours to match my readings. This set up should result in a trace but trigger light OFF. My trigger light is on.

Scope set up:

Channel 1: 1v/div, GND. No signal.
Int Trig set to channel 1
Time/div set to 1mS
Horiz Display to A
Sweep Mode to Auto Trig
Slope to +
Level to slightly negative
A Trig Coupling to AC
A Trig Source to INT

DC voltages on U780:

Pin 1  +0.495V        Pin 11  +5.518V
Pin 2   +0.0789V     Pin 12  +0.0108V
Pin 3   +0.3027V     Pin 13   0
Pin 4   +4.981V       Pin 14  +4.945V
Pin 5   -4.961V        Pin 15  +0.8714V
Pin 6   +0.0291V     Pin 16   0
Pin 7   +0.4347V     Pin 17   -0.4684V
Pin 8   +0.6746V     Pin 18   0
Pin 9   0                   Pin 19   0
Pin 10  0                  Pin 20  +4.980V

And some waveforms:

Pin 17  x1 probe. AC coupled. 0.5V/div 2mS (There is no pulse at pin 16 and I think there should be)



Q816 base. x1 probe. AC coupled 0.1V/div 2mS



J816 x1 probe. AC coupled. 0.5V/div 2mS



Thanks!! 

[0culus]

Got another fully functioning P6201 probe and a lot of accessories I didn't have today, especially nice are probe tip to BNC adapters. Also, property tag pr0n...this probe belonged to DEC! My third P6201 (which is sadly not complete, I only have the probe body basically) has Boeing tags. 

[xrunner]

Also, property tag pr0n...this probe belonged to DEC!

Ha that's cool. 

[ArthurDent]

Here are some more tubes that I have that may not be that common.

In the photo of the end view Nixies there is a small RCA Numitron which has incandescent filaments. These 7-segment displays didn’t last long with LED doing the same thing better and cheaper.

The nimo 64 I have is a strange cross between a regular display and a CRT. Another great marketing idea.

The 703 doorknob from around WWII was another strange UHF triode. I believe it was good to 20 watts.

The 0C3W gas filled voltage reference tube was in a special socket to allow it to operate at high altitude without exploding. There were a number of subminiature glass tubes like the one next to the 0C3W that were used in what was then compact equipment for the military.
 
The CRT in the photo was to give a wide view and the front was about 2”x4”.

[bitseeker]

Added those as a supplement link in the POI from your earlier post.

[Ero-Shan]

When I'm done with the 3460A I'll going to donate it to his collection.

I checked all the rubbish but I did not find any debris from the switch.
So, it was very likely broken before.

Do you know by any chance a source where to get this plastic knob? 

I know this reply is way out of time; seems I didn't check in here for a whole week. There will be lots of reading to do ...

A direct question deserves a direct answer: I'm afraid not. Is that knob real (thermo-)'plastic'? Looks like bakelite to me.
Your best bet might be a 3DP.

Sorry.

[VK5RC]

Grey hair!
Who has hair?!

[beanflying]

Grey hair!
Who has hair?!

When it starts growing out of your ears more than on top take what you can get 

[tggzzz]

Tggzzz, if you get a chance to open up your 485 this week these are the parameters you should set up on yours to match my readings. This set up should result in a trace but trigger light OFF. My trigger light is on.

That list is exactly what I want.

I'll try, but as an extra load I now have to replace a hatch door onto my mother's roof, since it has become edible. Seriously!

And then there's getting in Brexit supplies so she can continue to feed herself with nutritious ready meals. Normally would use chlled/frozen, but the fridge/freezer space is too limited.

Life was simpler before I retired.

[Ero-Shan]

Good thing you guys have been discussing Star Trek, Star Wars or whatever because I've been up to my ass in alligators all day and I don't follow those shows so I didn't miss much. 

This POS 485. I did some research and I discovered that the 465, 465B, 475A, and 7B80 plug-in all use that same P/N Trigger IC as the 485. So I'm all encouraged that I'll finally fix it. I have 2 of those IC's in my parts mules. So first I change out the IC itself. No fix. Same symptoms. OK, no problem. I look over the trigger schematics for the 465/475 and while they use that same IC the supporting circuitry is so different that there's almost no correlation. But I did get some clues on how I think that 20 pin IC is supposed to work. And I've been trying to troubleshoot and determine what's wrong for the past several hours. I've come to the point where I believe the IC is missing a reset pulse. This is causing it to lock up and therefore no sweep trigger. I found the pulse but it's not getting to pin 16 of the IC and believe it or not can't figure out why. I've checked every component in that circuit plus even trace continuity. Everything appears OK. But no reset pulse. At this point I'm out of ideas so it will once again be put off aside until tggzzz comes back and can open up his 485.   

Seems you missed my reply to your inquiry about the IC's voltages. I had my 485 open all week ... But I didn't return to this thread until today.
Now the 485 is whole again and tgzzz has probably help you already.
Guess I will have learned when I finally caught up.

[VK5RC]

Grey hair!
Who has hair?!

When it starts growing out of your ears more than on top take what you can get 

Nearly fell off my chair😂
So true!

[Ero-Shan]

I cannot help myself, but this Rolls Royce Flying Bedstead reminds me to one of these:

Space 1999! That show was a looong time ago. I can barely remember watching it.

Never get warm with Space 1999. But I sure loved its precursor, U.F.O. ARD alpha (an educational channel!) aired all episodes last year (uncut, unlike ZDF in the early seventies, and in English). Recorded them all, but sadly missed one due to a different schedule because of a holiday.

[Mr. Scram]

What is this 'sell' thing of which you speak??   

-Pat

It's like when something breaks and you stuff it in a corner except that it's actually not in that corner and your pockets are suddenly slightly less empty.

[med6753]

Tggzzz, if you get a chance to open up your 485 this week these are the parameters you should set up on yours to match my readings. This set up should result in a trace but trigger light OFF. My trigger light is on.

That list is exactly what I want.

I'll try, but as an extra load I now have to replace a hatch door onto my mother's roof, since it has become edible. Seriously!

And then there's getting in Brexit supplies so she can continue to feed herself with nutritious ready meals. Normally would use chlled/frozen, but the fridge/freezer space is too limited.

Life was simpler before I retired.

No hurry...whenever you get to it.

[med6753]

Good thing you guys have been discussing Star Trek, Star Wars or whatever because I've been up to my ass in alligators all day and I don't follow those shows so I didn't miss much. 

This POS 485. I did some research and I discovered that the 465, 465B, 475A, and 7B80 plug-in all use that same P/N Trigger IC as the 485. So I'm all encouraged that I'll finally fix it. I have 2 of those IC's in my parts mules. So first I change out the IC itself. No fix. Same symptoms. OK, no problem. I look over the trigger schematics for the 465/475 and while they use that same IC the supporting circuitry is so different that there's almost no correlation. But I did get some clues on how I think that 20 pin IC is supposed to work. And I've been trying to troubleshoot and determine what's wrong for the past several hours. I've come to the point where I believe the IC is missing a reset pulse. This is causing it to lock up and therefore no sweep trigger. I found the pulse but it's not getting to pin 16 of the IC and believe it or not can't figure out why. I've checked every component in that circuit plus even trace continuity. Everything appears OK. But no reset pulse. At this point I'm out of ideas so it will once again be put off aside until tggzzz comes back and can open up his 485.   

Seems you missed my reply to your inquiry about the IC's voltages. I had my 485 open all week ... But I didn't return to this thread until today.
Now the 485 is whole again and tgzzz has probably help you already.
Guess I will have learned when I finally caught up.

I saw your reply and your readings were most helpful. Thanks.  But I've since done additional troubleshooting and set the scope up with different parameters which required a new set of readings.

[BU508A]

When I'm done with the 3460A I'll going to donate it to his collection.

I checked all the rubbish but I did not find any debris from the switch.
So, it was very likely broken before.

Do you know by any chance a source where to get this plastic knob? 

I know this reply is way out of time; seems I didn't check in here for a whole week. There will be lots of reading to do ...

A direct question deserves a direct answer: I'm afraid not. Is that knob real (thermo-)'plastic'? Looks like bakelite to me.
Your best bet might be a 3DP.

Sorry.

Thanks for your answer. 
Yes, the knob is made of Bakelite and I found one in the US. Shipping costs are really a PITA.

https://www.ebay.com/itm/123832283457

[factory]

Thanks for your answer. 
Yes, the knob is made of Bakelite and I found one in the US. Shipping costs are really a PITA.

https://www.ebay.com/itm/123832283457

Is that the one you ordered for your 3460A? As it's nearly double the size of the original and is usually found as the main range selector on the VTVM's.

David

P.S. Here are the modifications for the H04-3460A version, they added 11 pages to the inside cover of the 3460A manual.

[BU508A]

Thanks for your answer. 
Yes, the knob is made of Bakelite and I found one in the US. Shipping costs are really a PITA.

https://www.ebay.com/itm/123832283457

Is that the one you ordered for your 3460A? As it's nearly double the size of the original and is usually found as the main range selector on the VTVM's.

David

P.S. Here are the modifications for the H04-3460A version, they added 11 pages to the inside cover of the 3460A manual.

Argh! those damned Inch units! 

[med6753]

Another TEA related woodworking project built up and needing 2 coats of poly then it's show and tell. 

[mnementh]

Because 4 wasn't enough.

mnem

[mnementh]

This will not end well.

mnem

[med6753]

Why 8 casters? And is that a gas valve you're messing with? 

I'm glad you're in Texas so the explosion will be just a whimper here.   

[BU508A]

This will not end well.

In the end, all is well.
And if it is not all well, then it is not the end.
 


You can do it! 

.oO(whatever "it" is)

[mnementh]

Thanks for your answer. 
Yes, the knob is made of Bakelite and I found one in the US. Shipping costs are really a PITA.

https://www.ebay.com/itm/123832283457

Is that the one you ordered for your 3460A? As it's nearly double the size of the original and is usually found as the main range selector on the VTVM's.

David

P.S. Here are the modifications for the H04-3460A version, they added 11 pages to the inside cover of the 3460A manual.

Argh! those damned Inch units!   

mnem