Test Equipment Anonymous (TEA) group therapy thread

[factory]

And look at all those lovely SK* sockets just waiting to be jiggled and deoxidised

Yes as it failed when shipped, hopefully it's just a bad connection.

And be careful if probing the display ICs, shorting the HT rail to the low voltage parts will probably not end well, which reminds me of that Philips counter I ruined with a probe slip.... 
            ....it's still here waiting for me to have another go at fixing it.

David

[PascalNE]

Thanks everyone for all your advice. Only annoyed Im away till Tuesday and can’t try things sooner!

[factory]

The non-working 70755 GPIB option, could the ribbon connectors be at fault? There are three inside the 7075 and a bunch more inside the module itself, repair info & diagrams are in the 7075 technical manual.
Might be worth collecting the contents of the six PROMs somewhere too.

David

[tggzzz]

The non-working 70755 GPIB option, could the ribbon connectors be at fault? There are three inside the 7075 and a bunch more inside the module itself, repair info & diagrams are in the 7075 technical manual.
Might be worth collecting the contents of the six PROMs somewhere too.

David

Take the 70755 off, and it will probably be possible to find useful information on the 50 way D connector. There's no microprocessor, so the interface will be pretty simple conceptually.

That might make it possible to indicate the problem is in the display section, or digital section, or elsewhere.

[AVGresponding]

Selling working instruments in bits is what 'MJ' does, try not to copy them, it pisses me off no end, knowing they parted out some rare TE and stuff where I was the second highest bidder.
It would bother me slightly less it they didn't take the piss with the asking prices on parts, often one part is more the what it sold for complete & working.

David

Yep, scumbags like mjlorton are why we have a members only buy-sell-wanted section in The Other Place

[TERRA Operative]

What, that youtube guy is stripping working gear to sell for parts???

[Robert763]

A package arrived from Digikey yesterday. A pack of EE2-4.5TNU relays (Dual coil latching in SMD package) and a long fine cranked tip for the Metcal.
Time to replace the relays on the Advantest / ADCMT 7461A DMM.
First issue is the correct relay is EE2-4.5TNUN. This is a "reduced footprint" version. Basically the dit of the leg in contact with the PCB is shorter. Thery re not a stock item but the EE2-4.5TNU is. Easily sorted out with a small pair of flush cutters. IT does show how tight the mounting of these relays is.
Removal of old relays was by cutting the legs with my smallest pair of lindstrom side cutters. Cleaned up the pads and soldered on the new relays.
And it works. 

However this thng is a pig to work on. The plastic parts have become brittle (date codes in IC's indicate it is no more than 20 years old) and break at the slightest touch and there is no technical information available.
I won't be buying another one.

NUN seems to be an option from NEC, seems Kemet/Yageo no longer produce it and they have elimated any reference to it the current datasheet.
There were other brands making these telecom type relays, just can't remember them at the moment.

Did you take any pictures when you had the DMM open for repairs?

David

Yes I did 
You can see it is mostly standard parts other than a couple of resistor networks. No high precsion components. They must be relying on stability and stored calibration offsets.
Robert.

[wkb]

What, that youtube guy is stripping working gear to sell for parts???

I suppose you want him excommunicated?

[factory]

What, that youtube guy is stripping working gear to sell for parts???

I suppose you want him excommunicated?

No it not him.

It's a UK dealer that buys TE and advertises the parts on feeBay in the UK.

Yep, scumbags like mjlorton are why we have a members only buy-sell-wanted section in The Other Place

That would make no difference, the UK dealer is searching feeBay & probably other places, the same as we do.

Example below of rare working TE that was bought on feeBay (at approx £100 from scottrade) and parted out & bits advertised at crazy prices.
The Fluke 8375 I asked about on here was another rare TE, it wasn’t functional & I didn't know if it was complete at the time, but would now, since the manual is on archive org.

David

[wkb]

What, that youtube guy is stripping working gear to sell for parts???

I suppose you want him excommunicated?

No it not him.

It's a UK dealer that buys TE and advertises the parts on feeBay in the UK.

David

Terra was refering to mjlorton on YouTube. But regardless: lets excommunicate brainless TE breakers 

[factory]

I'd not actually heard of mjlorton before, can't imagine they would be buying much from here anyway. Yes I excommunicate known TE breaking dealers & even one TE breaker on this forum.

Did you take any pictures when you had the DMM open for repairs?

David

Yes I did 
You can see it is mostly standard parts other than a couple of resistor networks. No high precsion components. They must be relying on stability and stored calibration offsets.
Robert.

Guessing the ref is the LT1027, next to some of those custom resistor networks.
And I see what you mean by the short leads on the NEC relays, not sure why they used those, given there is space around them.

David

[madao]

TE Breaker, you can added Max Koschuh to "TE Breaker" bzw  Röhrengeier (german tube vulture, raped HP/Tek for audiofool-tube )

[AVGresponding]

Selling working instruments in bits is what 'MJ' does, try not to copy them, it pisses me off no end, knowing they parted out some rare TE and stuff where I was the second highest bidder.
It would bother me slightly less it they didn't take the piss with the asking prices on parts, often one part is more the what it sold for complete & working.

David

Yep, scumbags like mjlorton are why we have a members only buy-sell-wanted section in The Other Place

mjtronix, not mjlorton, apologies 😓

[TERRA Operative]

Ah, crisis averted!

[Hydron]

Yeah and mjtronix has little to no docs/specs on most of the components, so they're worth far less after being stripped from an unnamed instrument than they would be if you at least knew where they came from. Wouldn't be so bad if he just attacked old military gear that isn't really amenable to use outside that environment, but all manner of good usable/fixable TE is also ruined by that damn butcher.

[Robert763]

I've stopped looking at his listings. It's not good for my blood pressure.

Robert.

[wkb]

Ah, crisis averted!

Amen to that!

[EggertEnjoyer123]

I got a Telequipment CT71 curve tracer for a low price from the ewaste.

Has anyone 3D printed a replacement knob for these? I'd prefer if I didn't have to draw it up in CAD. Also I'm missing the box so I'm probably going to have to 3D print a replacement for that too.

Edit: https://www.printables.com/model/113790-telequipment-ct71-curve-tracer-knob/remixes

[tautech]

Being a '71 vintage or later, more Tek than Telequipment so Tek knobs will very likely fit.
https://w140.com/tekwiki/wiki/Telequipment_CT71

[Ice-Tea]

HP 8156A (optical attenuator) presents with a "FAIL0040" error. Opened her up, vaguely hoping it would be the CMOS battery or something.



Seems the previous owner also opened her up. And didn't put the hood back on. And pulled so hard on the PCB that it cracked. And lost the hood  Even if I could figure it out and repair, I probably still can't sell it. I'm guessing that optical mirror being contaminated with dust is not a good thing.



You can't win them all I suppose but at least I had a learning experience. Optical is black voodoo to me, but seeing this makes a lot of sense. The input passes a lightguide to line it up. There's a rotating mirror placed under an angle so it reflects back to the output. I'm guessing that the mirror has a gradient or something so rotating it changes the attenuation.

[m k]

Can you test it?

Light is a nasty bugger to deal with.
Acoustic beam shaper was one solution.
Latest laser I've had to fiddle was Linotronic 500, pretty fresh, eh.
(it's a film printer and time was this millennia)

Since the light likes to "fold" it's route must be kept materially homogeneous.
Air is just fine for straight stuff, but deflection is different.

That old Lino has five beam deflection points, if memory serves.
Including one rotating hexagon and one curved convergence mirror.
(and a mechanical attenuation wheel with dimming glasses)
To keep things in order all of them are deflecting from the surface.

On the other hand it's light, nothing more.
For film printer it means that no darkness and the film is gray.
Unfortunately placed dust particle and a dot is nowhere or somewhere else.
(don't sneeze when cleaning is almost done)

So clean the glass like you'd clean your eye, no scratches, no harmful chemicals and no leftovers.
Repair the PCB, add a new cover and sell it for secondary projects.

[Shimonu]

I got a couple of faulty frequency counter yesterday. A Philips PM 6669 and an HP 5315A.
My suspicion is that the seller of the HP didn't quite know how to use a frequency counter as they said it wouldn't show anything when connecting a signal on the input. My guess is they didn't adjust the sensitivity because it worked fine when I got it and haven't had that kind of problem. On the other hand it was behaving strangely and would seemingly enter the display check for no reason. That just turned out to be some dirty switches and after cleaning it seems to work great!

The Philips had a strange problem, it has the battery option and it wouldn't show any count if the plug was connected together with the battery but it worked fine on each power source separately. It turned out to be a broken output pin on a 7905 which I've resoldered temporarily.

Today I've also got a DMMCheckPlus, lovely little thing. Pretty handy for checking all the functions of repaired multimeters or even an LCR meter.

Yeah, I'm starting to like this hobby.

[wkb]

Now this followed me home, so I have an infinite IQ rabbit hole to explore   

A day on which you did not learn something is a day not lived...

[Ice-Tea]

Can you test it?

Maybe, not sure...

So clean the glass like you'd clean your eye, no scratches, no harmful chemicals and no leftovers.
Repair the PCB, add a new cover and sell it for secondary projects.

Doesn't solve the Fail. In addition: not worth my time. There's no way I could sell it full price (at least not while staying honnest) and at anything less than full price it rapidly descends in 'not economic to repair' territory. Probably will keep it around for parts (the display and the PSU are shared with other devices I think). Or, if someone is willing to fork over the price of a display, it's theirs ;-)

EDIT: Another class of instruments I have little experience with. R&S ESCS30. So many questions, so much to learn!

[Ice-Tea]

WHAT IS THIS ALL DOING HERE???