Test Equipment Anonymous (TEA) group therapy thread

[Neomys Sapiens]

In case someone has a Tek curve tracer and no adaptor heads for it:
https://www.ebay.de/itm/166380523963?hash=item26bd0d51bb:g:R1wAAOSwBuBlLO8~

[Vince]

How timely, I just happened to be playing with mine just 10 minutes ago ! 

... unfortunately mine is a 575 and these adapters are advertised as being for a 577 and looking at pics of the latter, the layout of the jacks seems incompatible.
Oh well...

The TO-3 adapter would have been particularly useful  !

If you find the same adapters for a 575 tracer, don't hesitate to post about it ! 
Well that's assuming such adapters even existed, I have no idea... but I guess I could check old Tek catalogues to see if they listed such accessories...

I guess I could fabricate my own adapters, and try to make them look "vintage" in some way, somehow, so as to blend with the looks of a 575..

[TERRA Operative]

Oohhh nice. I have a 577...

Too bad no shipping to Japan, besides the exchange rate being crap and I already spent too much on stuff recently.

[TERRA Operative]

Today was 'working on car day' followed by calibrating some THS720 scopes.

The passenger wing mirror was screaming every time it folded in and out (which was every time the car was locked and unlocked), and after managing to remove the motor/gearbox assembly from the mirror, it turned out to be dead bushings in the actual motor. Luckily I had a spare assembly, so into the bin with the old and into the mirror with the new.

I also took the chance to add the option LED illumination that I've had sitting in a box for an embarrasingly long time... It shines down onto the ground from under the mirrors when you unlock the car so you don't step in a hole or a puddle or a dog poo or something.

https://youtu.be/ZafSkqu4-cA



Then, the three Tek THS720 scopes got calibrated. I'll keep the nice THS720P (With bag and almost all accessories) and sell of the THS720STD and THS720A that I upgraded to THS720P.
I updated the firmware from a flash chip image, but that includes the cal data from the original scope that the flash was copied from, so a recal is needed after the update.
If the proper Tek process is done, it only flashes the firmware part of the memory so recal isn't needed. So far I have found all the required info to do it, bar the actual hardware. The PCB in the programming pod is reproducible, but a 'Motorola M68332BCCDI 'DIBUG' debug module' is needed which seems to be really super rare these days.
I'm pretty sure with some reverse engineering, a Raspberry Pi of some sort could be made to be a fully self contained programmer, however I don't have the skills, and I just recalibrated my scope anyway so... meh....


Next is to finish troubleshooting this Korg X-911 guitar synth that a friend gave me to repair. After replacing all the capacitors (some were leaky), repairing a hole punched in the PCB from a too-long stand screw being used, deoxit everywhere and a good general cleanup, it is still playing games. I thing that screw may have shorted out something and made it go pop, deeper investigation required...

[Vince]

Well that was a busy day for Terra.... Toyota has some fancy options it looks like ! 
I am not that fussy...

It was car day for me too, spent 4 hours non-stop trying to investigate, and fix some, of the countless problems that the driver's door suffers from. At 24 years and 320.000kms, my Safrane is showing its age, I guess... can't blame her for that.
Still not finished but it's dark so I put it half back together, temporarily just so I can drive the car to work... and will continue my investigations in the coming days, as weather allows (no garage at home for now). I am exhausted.

No TE was involved, and only minor electronics : the electric window and its electronic controller. 

So not much to speak about...

No scope calibration for me...

[W6EL]

Vince,

I brought my car to my mechanic once in about the same state, door all tore apart and screws everywhere. I was about at my limit with the stupid window motor and it's screws which are only accessible, ultimately, from inside the door. Guy looks at me, looks at the door, looks back at me. "Go home, we'll fix it"

Gave me a discount on the labor too since it was already all taken apart .

--E

[m k]

My take is that wires have become too stiff and are braking around the inlet.

[m k]

also one part came off with the tape.

That is not nice.

You must expect similar stuff everywhere.

[W6EL]

Got this HP 3400A  on a bit of a gamble from ebay recently. $75. Seller says it sat in storage for 20 years and he can't find the power cord. Unlike a lot of these meters that are affordable and in pieces, this one, aside from some yellowing, looked pretty good. There wasn't any paint peeling and it was dent-free.

I looked inside. There's sticky "dots" of stuff everywhere. My guess is some capacitors outgassed slowly in a hot environment and this is basically electrolytic goo that was airborne and collected in random places. Everything is sticky. Many capacitors look quite suspect.

Now, you'd think I'd then take it apart and replace all the electrolytic parts, right? Well.. that was the plan for a few minutes. Then I decided to just bring it up softly (2 minute VARIAC turn) and see what happened.

It works. And not only that, but it is nearly in-cal. The switch and BNC connector need a good cleaning, but otherwise, it's really pretty good. I will still replace the caps, but I can now enjoy doing so at my own pace, as I know the entire thing basically works fine. I verified flat response up to 15 MHz, and degraded performance above this frequency by so many dB. Basically in-spec.

Oh, and the date? "8 67" is stamped on the side, and the meter shows 6-11-63 inside. Looks all original. Maybe it even has the germanium transistors, we will see. I just can't believe it's not more broken. I watched some youtube videos on these meters where guys spent several episodes replacing parts and chasing down issues.

[factory]

Nice early one, still with the original optical chopper board too. 
I've got one of the early chopper board designs, not working of course, kind of hoping some boards would appear cheap, since people have been fitting modern IC based boards.

P.S. don't forgot to check for rotting foam that isolates the Nuvistor board.

David

[TERRA Operative]

I wonder how many of those carbon composite resistors are still in tolerance too?

I have found they have often drifted waayy out.

[W6EL]

I am sure they are WAY out. But I guess they drifted together enough that it's still within 10% calibration. Possibly even better. Compared to all my equipment, the readings are within a "hair or two". I'll have to make a closer comparison later.

But to your point, yeah, new carbon resistors are one thing, and 50 year old carbon resistors... yeah. I am sure I will find a lot of things are way out of alignment inside. Any instrument used for precision measurement should not have a single carbon resistor, if you ask me. It just all depends on how much time I want to spend on it. I will replace basically all the caps for sure. Currently wondering if I need to maintain that some are tantalum or if I can just use standard electrolytic caps. My feeling is the tantalum caps were chosen due to higher temperature stability of the ESR compared with aluminum electrolytic. But who knows. I could almost re-cap it with what I have on-hand this evening if aluminum electrolytics are acceptable.

Ok now for a fun question... I also have an HP 3490A on the way. I am wondering if I could place a modern RMS-to-DC converter inside it. I see that there is an input attenuator which is supposed to bring the input voltage down to 1 volt at full-scale. I am thinking I could put a chip or hybrid right there, and then remove the rectifier stage which is after the 20x amplifier. But I am not sure. I don't need another not-really-RMS meter. And I think it would be fun to try. I could possibly also bump up the bandwidth during this modification too, depending upon how much is there with the existing circuitry of the attenuator of course. Thoughts? Recommended modern RMS chips/hybrids?

[W6EL]

David,

Do you have a photo of the original foam around the nuvistor? I looked, indeed, no foam here except for some little bits of brown foam floating around. I can't even tell where it once was. Is it just a piece glued to the outer panel perhaps?

Thanks,

--E
de W6EL

[TERRA Operative]

I'm restoring a Yokogawa 2853 DC Volt/Current standard. It only has one PCB, so I replaced all the carbon comp resistors with 50ppm metal films for fun (along with new caps).

Will be interesting to see how well it performs against rated specs once I get it all repainted and reassembled.

[m k]

I looked inside. There's sticky "dots" of stuff everywhere.

Scoop some sticky stuff and try dissolving it.
Maybe it has inhabited a sticky stuff factory in its early life.
Though exterior indicates something different.

Plastic and rubber can also degenerate over time.

Fly shit around here is usually dark.
And can create a tincture of ammonia when cleaned.

[factory]

David,

Do you have a photo of the original foam around the nuvistor? I looked, indeed, no foam here except for some little bits of brown foam floating around. I can't even tell where it once was. Is it just a piece glued to the outer panel perhaps?

Thanks,

--E
de W6EL

They all suffer from this foam turning to dust & it gets everywhere underneath.



These pictures are from the parts mule (dead thermocouple), that was used to repair several others with failed unobtainium parts.






P.S. I find the Allen Bradley carbon comps that HP used aren't that bad, other brands with moulded casings are crap. As your 3400A is working, they can't be that bad either. As always YMMV.

David

[W6EL]

Ahh thank you, David, this clarifies a lot.

Was the foam just to provide a soft mechanical mount, to protect the nuvistor?

I have some ESD-safe foam I can stuff in mine.

--E
de W6EL

[factory]

Soft foam (probably polyurethane based) , same as used on the oscilloscope front ends, to reduce vibration related micro-phonics/noise.

David

[med6753]

Got this HP 3400A  on a bit of a gamble from ebay recently. $75. Seller says it sat in storage for 20 years and he can't find the power cord. Unlike a lot of these meters that are affordable and in pieces, this one, aside from some yellowing, looked pretty good. There wasn't any paint peeling and it was dent-free.

I looked inside. There's sticky "dots" of stuff everywhere. My guess is some capacitors outgassed slowly in a hot environment and this is basically electrolytic goo that was airborne and collected in random places. Everything is sticky. Many capacitors look quite suspect.

Now, you'd think I'd then take it apart and replace all the electrolytic parts, right? Well.. that was the plan for a few minutes. Then I decided to just bring it up softly (2 minute VARIAC turn) and see what happened.

It works. And not only that, but it is nearly in-cal. The switch and BNC connector need a good cleaning, but otherwise, it's really pretty good. I will still replace the caps, but I can now enjoy doing so at my own pace, as I know the entire thing basically works fine. I verified flat response up to 15 MHz, and degraded performance above this frequency by so many dB. Basically in-spec.

Oh, and the date? "8 67" is stamped on the side, and the meter shows 6-11-63 inside. Looks all original. Maybe it even has the germanium transistors, we will see. I just can't believe it's not more broken. I watched some youtube videos on these meters where guys spent several episodes replacing parts and chasing down issues.

That is the clear plastic on the body of the capacitors breaking down. It does not affect them electrically, it just looks bad and they may test good. I've encountered the same on many old Tek units too. To be on the safe side I replace them all.   

[soubitos]

I have what appears to be an older model not halogen bulb and two cells unlike any I've ever seen before.. I guess NiCd but honestly have no clue what we're talking about LOL
Any idea what I can use to replace those with?

[Robert763]

Picked up some sort-of TE. It's a Heim/Racal/Thales digital instrumentation recorder. Model is DATaRec A480. it was obviously intened to replace the huge multi-track FM and PCM instrumentation recorders that used 2" tape on open reels made by SE Labs etc.
As you can see it is reasonably small. Whwt is not obvious is it is very dense! There are more slots on the back for a total, with the modules fitted, of 32 channels. Each of these has a 24 bit ADC and 48 kHz sample rate. As well as a bunch of analog IC's each module has a Motorola DSP and Altera FPGA.
I can't find any manuals so far. Unfortunatly the product range seems to have been subject to a lot of mergers and takeovers. Currently seems to be under the Thales group so getting info may be a problem. It records to a Sony AIT-2 8mm data cartridge. There are options for replacing that with Compact Flash but no point looking if I can't get a manual.
I switched it from 115V to 240V, plugged it inand it lit up. It then ran self-test and internal calibration routines and it all passed. The bargraphs respond to signals at the input.

If I can't get manuals it will have to be scrapped which would be a shame. It must have cost tens of thousands when new 20 odd years ago. I have a lot invested in it. It had been re-listed on ebay at least twice due to no bids. I won it with a maiden bid. Collection only and about 80 miles away.
BUT: only a 3 mile detour from a trip I was making anyway and my bid was 1p. Yes £0.01 

Quick update on this. Could not find any manuals for this from the usual places on the web. The Internet Archive / Wayback machine found some ols site with ads but no data.
Without much hope I sent a friendly email to a UK company who used to be a supplier of the recorder. Lo and behold they came back with PDF's of the data sheets, user manual and technical manual. 
A quick read of the manuals showed that the 32 input channels are single ended or differential +-30mV to +- 30V etc. It also has four two channel function generator output modules.
Even better, the manual revealed the name of the configuration software and the because it suppoerts later models it' still available. Even better it's free. Downloaded it and it seems to run but have not connected to the recorder yet. It also allows you to download data directly from the recorder.
Things are looking up, thei recorder may yet have a new life.

[Vince]

Wow good on that company, helpful.... they don't make them like this anymore 

Glad you can now make use of it...

[EE4all]

Just scored my unicorn, the 85645a, working.

The 8563e is a low hours unit, bought broken a few years back. I needed to put a new YTO in. I also fully recapped it since I had 2 others that needed power supply repairs, so I made a parts order big enough to recap them all while I was in there. This is the one I kept, along with adding all the options.

At the time of the 8563e repair, I only did a minimal alignment, but now it's deserving of a full go through. The 85645a probably has Rifa's like the 8563e does, so it will eventually get the full go through as well.

  

[W6EL]

med6753,

I think you are correct. I don't see nearly as much of this stuff on the other components.

I assume the capacitors with the "+" indicated are tantalum, is that a safe bet? Is it going to matter much if I put aluminum electrolytics instead?

Thank you all for your ideas,

--E
de W6EL

[tautech]

I assume the capacitors with the "+" indicated are tantalum, is that a safe bet? Is it going to matter much if I put aluminum electrolytics instead?

I would strongly suspect that unit is from the pre Tant era.
Most electrolytics won't be low ESR either but testing them will confirm that.
Sourcing axial Ecaps is getting harder....