Test Equipment Anonymous (TEA) group therapy thread

[m k]

Input switch(p.46/101) is marked as flight refueling.
Is it from airplane or translation something?

[doktor pyta]

@factory

The connector is similar or same type as in early Solarton and Dynamco.
I could't find the exact type in the doccumentation. Manual says only 'internal production'.
The front panel is heavily inspired by Dynamco voltmeters (attachment).


ELPO V-523 was simplest early design similar to Solartron LM902-2:
https://collection.sciencemuseumgroup.org.uk/objects/co8005839/digital-voltmeter-type-lm-902-2-serial-no-65286-by-solartron-laboratory-instruments-ltd

Next was the ELPO V-524 shown well on the german forum:
https://www.mikrocontroller.net/topic/450690

Last voltmeters from the ELPO V-52x series were two models: V-527 with functions DCV and R and autoranging; V-529 with DCV and ACV but without autoranging.
These meters were big, heavy and expensive so starting from approx 1974 they were replaced by the smaller integrating voltmeters which utilized TTLs and Linear ICs. It was V-530...  and later V-540... series manufactured under Meratronik brand.


I think Meratronik is best known for its volt- and multimeters V-640 and V-543 and RLC bridges.
Here You can find a technology-related channel of the guy who explains the design of both with nice camera shots /use english subtitles/.



BR

[Robert763]

Input switch(p.46/101) is marked as flight refueling.
Is it from airplane or translation something?
[/quote

Flight Refueling Ltd (Dorset England) made in-flight refueling equipment and other aircraft fuel system components. They were an early manufacturer of sealed reed switches. These were mainly used for float switches and level transmitters (swring of resistors, switches and magnetic float) but they also made reed relays. The reeds had many advantages for fuel systems including not exposing any arcing to the fuel vapour. They even moved into solid state relay manufacture because the (non-aviation) relay market was so strong.
I used to work for thir aircraft operating company FR Aviation. 

[factory]

@factory

The connector is similar or same type as in early Solarton and Dynamco.
I could't find the exact type in the doccumentation. Manual says only 'internal production'.
The front panel is heavily inspired by Dynamco voltmeters (attachment).


V-523 was simplest early design similar to Solartron LM902-2:
https://collection.sciencemuseumgroup.org.uk/objects/co8005839/digital-voltmeter-type-lm-902-2-serial-no-65286-by-solartron-laboratory-instruments-ltd

Next was the V-524 shown well on the german forum:
https://www.mikrocontroller.net/topic/450690

Last voltmeters from the V-52x series were two models: V-527 with functions DCV and R and autoranging; V-529 with DCV and ACV but without autoranging.
These meters were big, heavy and expensive so starting from approx 1974 they were replaced by the smaller integrating voltmeters which utilized TTLs and Linear ICs. It was V-530...  and later V-540... series.


I think Meratronik is best known for its volt- and multimeters V-640 and V-543 and RLC bridges.
Here You can find a technology-related channel of the guy who explains the design of both with nice camera shots /use english subtitles/.

BR

The Solartron & Dynamco both used connectors from P.E.T. (Precision Electronic Terminations), pictures & part numbers here for comparison; https://www.vintage-radio.net/forum/showthread.php?p=1550875

A bit of history on Dynamco DVMs, they were originally known as Digital Measurements Ltd.
I'm not 100% sure, but some ex-Solartron engineers left after Solartron was taken over by Schlumberger in the early 1960s, to either start or join D.M. Ltd./Dynamco.

I've got a photocopy of the Dynamco 2022 DVM manual, it's a little older & still uses some electrometer tubes, but there are some similarities with the circuitry for your Elpo DVM, there is no ohms or AC or auto ranging on this model. There are boards labelled; balance amplifier, reference amplifier, logic & trip and some double & triple bistable. It also uses the same AEI CK3 choppers, there are quite a few parts starting with DMS to make repairs harder.
I'm glad you found a picture of the 2022, I was beginning to think 'Mikedestroy'sstuff' had destroyed the last remaining one for youtube views. 

Thanks for the youtube links, I'll add them to my watchlist & hope the creator actually restored them. If I can ever find one of those later DVMs at a reasonable price, I will add it to my collection.

The earliest Solartron DVM I've acquired is this LM1010.2, I've even found a manual for it, it's currently in the repair queue. One thing I've noticed with older Solartron manuals, is they don't want users to attempt calibration and referred them to sending it back for cal, the manuals give very little details of the internal adjustments.

David

[m k]

How to find deals like that?

Actually that is not a real problem.
The real problem is how to get them home.

Some can advice what to do when you get boat loads.
But single item can be pretty much not available.

Maybe we should create a P&P ring.
Some countries have laws against middle men.
Means that sender is always responsible.

[Messtechniker]

Ive seen some chaps with a sack barrow coming to sales venues by train.

[factory]

A possible solution to the Fluke 8050A with bad LCD, some LEDs from hp, there is lots of info on how to modify these on the forum & elsewhere, I don't think I've seen anyone use the plus/minus LED, this might be due to almost no-one making them anymore.



David

[m k]

Is there room for glass tubes?

Or put LEDs  upside down and have an unique machine with upper dots.

[factory]

The row of LEDs are 50mm wide, I don't think I have anything glass that would fit the space, having said that the few I have are kept for repairing equipment that uses them. Don't think there is anything small & glass with the +/- & 1 in the same tube anyway. Plus there needs to be space above or below, for the other parts that were on the original LCD.

Also the hp LEDs only have one decimal point fitted in this size, it needs to be on the right for the DMM.

David

[TERRA Operative]

You could always go OLED like I'm doing with my HP gear....
(Link is a few posts back)

[AVGresponding]

You could cut a small piece from a lighting gel to tidy it up a bit

[themadhippy]

lighting gel to tidy it up a bit

bit of lee 106

[m k]

Also the hp LEDs only have one decimal point fitted in this size, it needs to be on the right for the DMM.

David

Yes, and upper dot is not really fancy anyway.

Another rarity, red 8062A, maybe I've seen it around here somewhere.
https://www.ebay.com/itm/394612629564

[timeandfrequency]

Another rarity, red 8062A, maybe I've seen it around here somewhere.
https://www.ebay.com/itm/394612629564

Looks like this one has been spray painted.

[unseenninja]

A question for those with the Peak DCA75 component tester, does anyone else have trouble with it testing 1N82x series reference Zeners? Mine fails to detect some of them, but these do test OK with the curve tracing software, note both the firmware & software are up to date.

David

Bit of a late reply, but my DCA75 detects a 1N829 as a simple PN junction with Vf=6.133V with both the previous and current releases of the firmware. So it's not just your example, it really does have a problem recognising these as Zener diodes.

[m k]

Another rarity, red 8062A, maybe I've seen it around here somewhere.
https://www.ebay.com/itm/394612629564

Looks like this one has been spray painted.

With possibly printed front label.

[duckduck]

Another antique device in the lab restored to its former glory. ELPO V-527 made in Poland in 1972. Loads of high quality imported components and neat assembly showing high technical culture.
<SNIP>

That's a beauty. What kind of display is that? I'm a sucker for TE with unusual displays.

[Vince]

Another rarity, red 8062A, maybe I've seen it around here somewhere.
https://www.ebay.com/itm/394612629564

Looks like this one has been spray painted.

Why.... oh why....  RIP 

[AVGresponding]

Another antique device in the lab restored to its former glory. ELPO V-527 made in Poland in 1972. Loads of high quality imported components and neat assembly showing high technical culture.
<SNIP>

That's a beauty. What kind of display is that? I'm a sucker for TE with unusual displays.

If you're referring to the Dynamco DM2022S, those are nixies, though they look unusually flat; may just be an optical illusion caused by the display filter

[factory]

They both use low voltage displays, I don't particularly want to mention the type on here.

David

[factory]

A question for those with the Peak DCA75 component tester, does anyone else have trouble with it testing 1N82x series reference Zeners? Mine fails to detect some of them, but these do test OK with the curve tracing software, note both the firmware & software are up to date.

David

Bit of a late reply, but my DCA75 detects a 1N829 as a simple PN junction with Vf=6.133V with both the previous and current releases of the firmware. So it's not just your example, it really does have a problem recognising these as Zener diodes.

Thanks for replying, I was going to add mine detects some 1N82x as a diode and some are not detected.
what I did notice is the parts from the same make/batch tend to test all the same, either as a diode or not detected.

All the 1N821 I have were tested last week, they all check within tolerance for voltage at 7.5mA, the flat line in the attached plot is a test lead not connected.
I didn't bother changing the Zener in the 6209A, after I realised it the reference was within the spec given in the manual.

P.S. did your DCA75 lose the sound with the current firmware (V23)?

David

[factory]

You could always go OLED like I'm doing with my HP gear....
(Link is a few posts back)

For some unknown reason I don't think anyone has tried that for the Fluke 8050A, it's beyond me as it would need something like a programmed 'MCU board' adding, I prefer programming with discrete parts & tin/lead alloy.

lighting gel to tidy it up a bit

bit of lee 106

Yes something like that would help, but I need to build & wire up the replacement board first, there are other things to complete first. Actually I may have some red/or orange filters here, from spares that were bought on evilbay.

P.S. the case needs a little filler, to fix damage to the top edge of the front panel, thinking it would look worse if I was to paint it afterwards now.

David

[Robert763]

A question for those with the Peak DCA75 component tester, does anyone else have trouble with it testing 1N82x series reference Zeners? Mine fails to detect some of them, but these do test OK with the curve tracing software, note both the firmware & software are up to date.

David

Bit of a late reply, but my DCA75 detects a 1N829 as a simple PN junction with Vf=6.133V with both the previous and current releases of the firmware. So it's not just your example, it really does have a problem recognising these as Zener diodes.

That's because they are not zener diodes. They are voltage references that do not have any forward conduction (below the breakdown voltage of the compensation junction.

[factory]

Have a look at the 1N829A in the die pictures thread, it contains two diodes in series, one of which is used as the reference Zener junction & the other a diode junction connected opposite for temperature compensation, both junctions balance the temperature coefficient, the better grades are selected for lower TC.

https://www.eevblog.com/forum/metrology/more-voltage-references-die-pictures/msg4262863/#msg4262863

A datasheet for temperature compensated reference Zeners that are still available;

https://www.mouser.co.uk/datasheet/2/268/1N821_1N829A_1-3499699.pdf

Any diode could become a Zener (with current/power limiting), but most have too high a breakdown voltage to be of much use for that.

This begs the question, what type of regular (non Zener) diode has a volt drop of 6.2V, for the Peak to determine it to be a diode & not a faulty part?

David

[ch_scr]

If you want to experiment, look at the 2dw232. Much the same idea as 1n82x, but "symmetrical" in construction (so either one can be zener / compensation diode), and with access to the "center point" as well.