Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 1632252 times)

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30600 on: May 03, 2019, 04:19:55 am »
mnem, as requested, comparison photos attached below.

This photos confirmed that the blue case is identical, while the back cover, the B version has a really tiny bump to accommodate the thicker internal axial fan, not suitable I guess.  :-//

Added to POI.

On we go with the Solartron week.

Today's episode is titled "The strange case of the 7061". Of course there'll be lots of biggish but useless pictures and some daft commentary.

Also added.

Warning....picture heavy post. 7904 Porn.

This one, too.

Another day in the Solartron week. Today we're going to take a look at the 7060.

I was not prepared for this Solartron mass ejection. :-DD Added.

We're not done yet. The Solartron week continues ...

My little stack of 7045s

Will it ever end? :-DD It's all good, really.
« Last Edit: May 03, 2019, 04:38:20 am by bitseeker »
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30601 on: May 03, 2019, 04:21:46 am »
I decided to try the old Dumont 274-A Oscillograph (I guess the word oscilloscope was not invented yet  :-DD) I got part of the lot I fetched earlier this week. The inside was kind of clean but was still waiting for an explosion when I plugged-in the beast. I was astonished to see that it was kind of working. Probably need a good recap though :-DD

Talking about caps I'm probably too young but it's the first time I see those brown capacitor in wax. They look like wine bottle cork.








Are you going to clean it up and get rid of the wax caps? Might not be the most useful scope by modern standards, but could still be a cool "conversation starter" in the lab.  :-+

Also interesting to contrast this "oscillograph" with the stuff Tektronix was making just a decade or two later and marvel about how fast 'scopes developed.
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30602 on: May 03, 2019, 04:23:03 am »
For things like this I bought a cheap USB-to-GPIB converter:



Works fine under Linux as a serial device. Haven't done much with it, though. So I don't know if or how the more 'interesting' parts like SRQ are working.

I'm not sure about the more advanced functionality, but in general, you should be fine if you're writing your own software to interface with it.
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30603 on: May 03, 2019, 04:27:34 am »
Speaking of making cakes: here are some examples of my production (this is another hobby of mine)  ;D



And yes, I DO live southern of the river Main.  8)

Woah, BU508A! That's a dangerously impressive other hobby.
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30604 on: May 03, 2019, 04:35:40 am »
No, I don't. I'm not good enough for them. But that's okay, because important to me is that the people like my cakes.
My reward is looking on their happy faces. :)

Seeing them does provide some happiness, but not like eating them does. ;D

Quote
Edit: Just for med: guess, what kind of cake this is:   >:D



Black Forest cake, of course. I was in the Black Forest a few years ago, watched a baker there make one with lots of kirschwasser and even more whipped cream. Then, I ate some of it. Yum!
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30605 on: May 03, 2019, 04:47:21 am »
I decided to try the old Dumont 274-A Oscillograph



Added to POI
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30606 on: May 03, 2019, 04:48:24 am »
Tuesday evening's find, from a trash barrel being used as storage for various types of electronics and cables.



Yes that's a Heath Voltage Reference Source from the M-E Lab Components series



It was, in the day, a pretty good voltage reference, accuracy "as allowed by 0.1% resistors" as it says in the catalog entry.







I haven't powered it up because one of the fuses, and the latching fuse cover are missing. The slow blow fuse on the line side is interesting:



Other than the catalog page and a webpage copy of the calibration procedure, I haven't found a manual or much else on it. I do know that it was produced for one year, in 1970.

I will probably make sure it works, calibrate it, play with it a bit to see how accurate it is and then ask if anyone more interested in collecting Heath gear than me wants to buy it.

And how I came to to be introduced to the trash barrel, well that's a story for another evening.
proceed until apprehended
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30607 on: May 03, 2019, 04:49:58 am »
Your TEAcquisition skills are making us look like slackers, wch! :-DD

(Added to the POI)
« Last Edit: May 03, 2019, 04:53:02 am by bitseeker »
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Offline Ero-Shan

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30608 on: May 03, 2019, 06:12:28 am »
YEA ME! Just won this fine example of a later HP 427A, looks to be in very good condition.
https://www.ebay.com/itm/Vtg-Hewlett-Packard-Voltmeter-427A-Volt-Meter-Tester-Excellent-Powers-Up-HP-/183787763383?_trksid=p2349526.m4383.l10137.c10&nordt=true&rt=nc&orig_cvip=true#viTabs_0

Damn! There was a 475 on German eBay that I wanted. And (once more) simply forgot to bid! I would have paid quite a bit more than the winning did. Although he might have topped me anyway, that was a very good chance that I missed. I feel miserable now.  :(
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30609 on: May 03, 2019, 06:31:20 am »
I decided to try the old Dumont 274-A Oscillograph (I guess the word oscilloscope was not invented yet  :-DD) I got part of the lot I fetched earlier this week. The inside was kind of clean but was still waiting for an explosion when I plugged-in the beast. I was astonished to see that it was kind of working. Probably need a good recap though :-DD

Talking about caps I'm probably too young but it's the first time I see those brown capacitor in wax. They look like wine bottle cork.








Are you going to clean it up and get rid of the wax caps? Might not be the most useful scope by modern standards, but could still be a cool "conversation starter" in the lab.  :-+

Also interesting to contrast this "oscillograph" with the stuff Tektronix was making just a decade or two later and marvel about how fast 'scopes developed.

Judging by the type of vacuum tubes used......all octal types and using a later obsolete "80" type for the rectifiers....would place this scope late 1930's, early 1940's.

The non-linear sweep is definitely caused by a leaky cap in the sweep circuit. All those tubular caps, especially the brown wax ones, are no good, guaranteed. Although even when everything was up to snuff these old scopes weren't very linear.   
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30610 on: May 03, 2019, 06:35:00 am »
YEA ME! Just won this fine example of a later HP 427A, looks to be in very good condition.
https://www.ebay.com/itm/Vtg-Hewlett-Packard-Voltmeter-427A-Volt-Meter-Tester-Excellent-Powers-Up-HP-/183787763383?_trksid=p2349526.m4383.l10137.c10&nordt=true&rt=nc&orig_cvip=true#viTabs_0

Damn! There was a 475 on German eBay that I wanted. And (once more) simply forgot to bid! I would have paid quite a bit more than the winning did. Although he might have topped me anyway, that was a very good chance that I missed. I feel miserable now.  :(

Sorry, but you can't have mine.  :P :P :-DD

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30611 on: May 03, 2019, 06:35:45 am »
I decided to try the old Dumont 274-A Oscillograph (I guess the word oscilloscope was not invented yet  :-DD) I got part of the lot I fetched earlier this week. The inside was kind of clean but was still waiting for an explosion when I plugged-in the beast. I was astonished to see that it was kind of working. Probably need a good recap though :-DD

Talking about caps I'm probably too young but it's the first time I see those brown capacitor in wax. They look like wine bottle cork.








Are you going to clean it up and get rid of the wax caps? Might not be the most useful scope by modern standards, but could still be a cool "conversation starter" in the lab.  :-+

Also interesting to contrast this "oscillograph" with the stuff Tektronix was making just a decade or two later and marvel about how fast 'scopes developed.

Judging by the type of vacuum tubes used......all octal types and using a later obsolete "80" type for the rectifiers....would place this scope late 1930's, early 1940's.

The non-linear sweep is definitely caused by a leaky cap in the sweep circuit. All those tubular caps, especially the brown wax ones, are no good, guaranteed. Although even when everything was up to snuff these old scopes weren't very linear.   
I was reading a bit about Dumont's history. It seems that the first Tektronix 'scope featuring the timebase we think of today basically killed their dominance of the market. I'm not sure I fully understand how the Dumont oscillograph worked as far as horizontal...
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30612 on: May 03, 2019, 06:51:02 am »
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30613 on: May 03, 2019, 06:51:35 am »
That Dumont scope used a dead simple recurrent sweep circuit and that type of circuit was used in post WW2 "hobby" scopes for the TV repair market. Heath scopes used that type of circuit right up into the 1960's. You set your rough horizontal sweep then adjusted the fine horizontal until the sweep locked....or I should say...at least slowed down so you could view it. It never locked for long, they would slowly drift.

Tektronix developed the much superior triggered sweep which is standard today on all analog and digital scopes.
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30614 on: May 03, 2019, 06:53:52 am »
https://www.oscilloscopemuseum.com/oscilloscope-dumont-274a-s1205.html

Looks like this site has some manuals.

That site says it dates to 1948. I think it's earlier than that.
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30615 on: May 03, 2019, 07:01:08 am »
That Dumont scope used a dead simple recurrent sweep circuit and that type of circuit was used in post WW2 "hobby" scopes for the TV repair market. Heath scopes used that type of circuit right up into the 1960's. You set your rough horizontal sweep then adjusted the fine horizontal until the sweep locked....or I should say...at least slowed down so you could view it. It never locked for long, they would slowly drift.

Tektronix developed the much superior triggered sweep which is standard today on all analog and digital scopes.

Interesting. I guess I'm too young to have encountered one of those 'scopes.  :-DD

https://www.oscilloscopemuseum.com/oscilloscope-dumont-274a-s1205.html

Looks like this site has some manuals.

That site says it dates to 1948. I think it's earlier than that.

Perhaps they were made till 1948? Would need to find a catalog to find out for sure.
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30616 on: May 03, 2019, 07:20:43 am »
Read all about Dumont here. Not only did they make test equipment but they were also a TV broadcast pioneer but were muscled out by CBS and NBC and went out of biz in 1956.

https://en.wikipedia.org/wiki/DuMont_Television_Network
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Offline Ero-Shan

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30617 on: May 03, 2019, 08:18:18 am »
So you thought it was finally over? Nah, you were wrong. It ain't over 'till the fat lady sings!

And the saga continues ...

... with the Solartron 7050 and its lookalikes. ;)

The 2 of them are not exactly the same. Do you spot the difference?



Yes, the upper one's almost spot on, while the lower one is a wee bit below.
No, of course it's the different displays. I can't remember having ever seen the breed between the standard bar displays (lower) and the dotted ones of some 70ies HP gear. To me this is absolutely gorgeous!

Resistance measurement didn't work at all with the upper, the numbers were all over the place. OK with the instrument at the bottom.

There's a marked scarceness of controls: Power switch and function selector, the latter with a cheapish appearance. Not much picture fodder, so let us remove the case (which is easily done):



A little more cramped than the 19″ models, but mostly fine.
Solartron uses some novel scheme for interconnecting the boards. These contact combs (lacking a better word) can be slid out and back again. This, however, gets a bit tricky when you can't see the contacts, as this comb is easily tilted a bit and misses them. It also means that operating the instrument while the boards are separated (so you have easy access to the base PCB) is not possible.



Without the daughter board:



On to the display:



These components look a bit fragile. And the front is not even flat!

I like this one. 5.1 digits (yep, max is 109999). The display sets it apart, the form factor allows finding a space for it. The non-working resistance measurement needs to be looked at (it's not the caps; they're all fine). Kinda neat. :)

But wait! It's got a step-brother. You have to look closely to see the difference: 7051 instead of 7050.



This one has a larger daughter PCB, the mother PCB seems to be the same. I have no idea what the real difference is.



But wait! It's also got a little brother that is missing the last digit. This one is called 7140. According to the service manual, the 7050, 7140 and 7144 belong to the 7050 family, but not the 7051.  :-//



This concludes the Solartron extravaganza. Now that the fat lady has done her part, the final curtain falls and I can go back to my lazy, slow pace.  :phew:

Thanks all of you for watching and not complaining about all those pics. :-DD
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30618 on: May 03, 2019, 08:52:14 am »





A little more cramped than the 19″ models, but mostly fine.
Solartron uses some novel scheme for interconnecting the boards. These contact combs (lacking a better word) can be slid out and back again. This, however, gets a bit tricky when you can't see the contacts, as this comb is easily tilted a bit and misses them. It also means that operating the instrument while the boards are separated (so you have easy access to the base PCB) is not possible.





Tek used same type interconnects on the Inverter/Regulator board in the 2465. Also the same concerns. Use care when reinserting them and also can't operate the PSU when the boards are separated.

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30619 on: May 03, 2019, 09:37:15 am »
Black Forest cake, of course. I was in the Black Forest a few years ago, watched a baker there make one with lots of kirschwasser and even more whipped cream. Then, I ate some of it. Yum!

 :-+ 100 gummipoints for bitseeker.  :D

If we should ever do a TEA meeting in real life, I promise, I'll bring some cakes of mine.
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Offline Ero-Shan

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30620 on: May 03, 2019, 11:32:13 am »
Now for a small relief.

Klein+Hummel Röhrenvoltmeter (VTVM) RV-12. According to radiomuseum.org it is of 1962 vintage.

Which company dealing with electronics did not offer their interpretation of the (presumably) same basic design?
Klein+Hummel, makers of studio and HiFi ecquipment, were assimilated in 2009 by Sennheiser, but they had and still have an excellent reputation.

You guessed right this time, again with the boring 10 V reference:



Note that the necessary 1 MΩ resistance is inserted. That looks rather good.
Resistances measurements are, well forget it. The needle points in the general direction of the value, but that's it.

The back of the steel case hasn't much to show but the single screw that holds it all together and the fuse holder/voltage selector and the power switch. Power cords were usually not detachable in those days. Which I don't like, as they need extra room when storing the device and they tend to tangle up with others.



Not too many surprises inside at first look, dust & rust:



Of course, after umpteen years in storage, the battery for Ohms draws some interest:

That is surely an 'interesting' design of a battery holder! The resistor is directly soldered to the battery cell. The clamp is fixed. The strain relief of the power cord can also be seen. I guess that is not the original technique.

The battery with the plastic spacer (or collar) and a slightly rusty spring.  :-DD



Despite some rust, that 20 year old battery did not leak and is still as good as new. Anyway, I decide to forget about Ohms here altogether, so I don't have to worry about the battery. If need be, I have means to measure resistance.  ;)

Although this machine is heavy metal inside out, it is not connected to protective earth. Looking at the flimsy insulation of the transformers primary wires (mustn't they be doubly insulated for Protection Class II?) sends a slight shiver up my spine. But then, why should they suddenly make a short to the chassis? That case is quite effective in protecting them.

And here is my second RV 12 (without dash), likely somewhat newer (and these knobs are never ever original!). Alas, it's movement window is shattered. And the measurement is noticeably off:



With this, there are signs of a previous battery leakage (but no battery). The power cord is certainly not the original (it looks like typical Telefunken) and there is absolutely no strain relief whatsoever! :palm:



The back either shows the instrument's schizophrenia, as it says 'RV-11', or they got swapped at birth. ;D

 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30621 on: May 03, 2019, 11:38:52 am »
Solartron uses some novel scheme for interconnecting the boards. These contact combs (lacking a better word) can be slid out and back again. This, however, gets a bit tricky when you can't see the contacts, as this comb is easily tilted a bit and misses them. It also means that operating the instrument while the boards are separated (so you have easy access to the base PCB) is not possible.



The 7075 is worse :(

Imagine having the red plastic carrier between the circuit boards, and not being able to see between the boards without removing them from the case.

Separating the boards is easy, reassembling them requires some trial and error.
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Offline Ero-Shan

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30622 on: May 03, 2019, 12:44:41 pm »
Solartron uses some novel scheme for interconnecting the boards. These contact combs (lacking a better word) can be slid out and back again. This, however, gets a bit tricky when you can't see the contacts, as this comb is easily tilted a bit and misses them. It also means that operating the instrument while the boards are separated (so you have easy access to the base PCB) is not possible.



The 7075 is worse :(

Imagine having the red plastic carrier between the circuit boards, and not being able to see between the boards without removing them from the case.

Separating the boards is easy, reassembling them requires some trial and error.

I really wonder what those designers think when they're choosing solutions like these. In manufacturing you can cope with that by using specialized tooling, but when they need repairs?

And these instruments are meant to be repaired! I cannot think of a viable excuse. Oh, sure I can: cost.
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30623 on: May 03, 2019, 12:46:32 pm »
Now for a small relief.

Klein+Hummel Röhrenvoltmeter (VTVM) RV-12. According to radiomuseum.org it is of 1962 vintage.


And you can tell where they got their inspiration. It's almost a direct copy of the Heath VTVM's of the same era.
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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #30624 on: May 03, 2019, 01:03:08 pm »
Now for a small relief.

Klein+Hummel Röhrenvoltmeter (VTVM) RV-12. According to radiomuseum.org it is of 1962 vintage.


And you can tell where they got their inspiration. It's almost a direct copy of the Heath VTVM's of the same era.
By comparison, Heathkit used lighter frames and power transformers though.

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