Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

Took no more than one hour to get things up again, but it woke people up properly and Words were had. Wonder if it helps.

I fear that like most catastrophes which don't wipe out half the planet, the decision will be made to treat further such problems as a matter for politics to handle rather than having actual people do anything, because money.    Certainly, much noise and lip service will be paid very publicly... but a few days into the next news cycle there will be something much more important to worry about. 

It's the connected-age equivalent to swapping one battery between an assortment of SEP Field generators rather than actually stopping the blood loss. 

The point where we discovered that the problem was already apparent was when we started talking to the official Critical National Infrastructure people at the Cabinet Office in our preparation for Y2K (yes, that long ago). So in this particular case the people who could have 'had words', or even ultimately got new laws passed if necessary were already in the loop.

The UK, then and still, has rather a laissez-faire attitude to these things and, although there were civil servants who were concerned and active in trying to get fragilities weeded out of the system, there wasn't any apparent political will to press the point. The attitude seemed to be "Let's try and coordinate, foster cooperation, but basically leave these good 'dot com' people to carry on with the business of making money as fast as possible". Let me be clear, there was good stuff came out of our discussions - had some disaster befallen us in the future I could get engineering staff through police cordons, we had critical people's mobile numbers put on the list of magic numbers that still worked when the plebs got locked out and so on - but I never got the feeling that any progress was made towards the sort of coordination that was needed while the UK's communications infrastructure was being completely reshaped by a bunch of companies all essentially working independently and in competition with each other.

Jeezus C... I was just being cynical. Somehow, the way you flatly confirmed that cynicism is just... SO much worse...

mnem
*toddles off to reconsider his priorities*

[xrunner]

Here ya go guys and gals. Because I care and I think about you and I want to help. You need to get this DMM because it flashes the correct jacks for your test leads.

I hope this may help you enjoy this great hobby more fully. 

Auto-Ranging KAIWEETS Digital Multimeter

[mnementh]

That meter is relabeled by pretty much everybody under the HT118A model number. Here's a good ol' boy doing a quick teardown & comparison against some name brand meters. We won't talk about his understanding of why the name brand meters are made the way they are...

mnem
 

[beanflying]

I hate seeing this sort of shit 

you can sold fixe that with special aluminium welding rods

Probably not. That's a die casting and the aluminium alloy used for die casting has a lot of silicon in it. It makes it expand ever so slightly as it freezes - which is great for die casting, but lousy for welding. When welding it as it all freezes the base casting metal expands, the filler metal shrinks and the whole thing either bends out of shape or in extreme cases just cracks again.

You can "stitch" cast ally back together using lead, but on something that small...  idk.
Only seen it used on HGV engine blocks.


EDIT: This link might provide some useful clues/inspiration?  https://www.metalockengineering.com/en/typical-repairs/metal-stitching/

It can be done with a dirt cheap butane torch and some filler rods and patience  https://www.eevblog.com/forum/testgear/hewlett-packard-740b-dc-standard-digital-voltmeter-(and-740a)/msg1419955/#msg1419955

[Specmaster]

I would check Vref pin to make sure it's not wrong (assume it's 2.5V). Then use a 3478A or something in 3V range very high impedance mode to measure differential voltage across the inputs of the MAX134 while the actual input terminals of the 4503 are shorted and make sure that is zero. That will isolate either the ADC support or the input circuitry. Then divide and conquer!

Ok, this is back on my bench again for another go at it, can I just check what you mean here? Check Vref on pin 26 and Ground and then differential check on the other inputs, Pins 16,17,18,19 and 20 with reference to what ground? pin 16 10M, pin17 1.11M, pin 17 and ground, pin 16 101K, Pin 18  and ground, pin19 10K and ground and pin 20, 1k and ground?                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

[Neomys Sapiens]

And here is some seriously sad news:
You might remember THIS item:

The wondrous little signal tracer, which made it finally to me thanks to <Worsthorse>, has arrived my desk...
and the the battery fungus got in before me.  I wondered all the time how and where the battery is. It turned out that you have to release the two tiny screws and pull out the back cap. That I saw a loose wire there right when opening it did not come as a surprise, because every battery change is going to put strain onto the AWG30 wires going to the phones jack on the rear cap.
BTW, it is smaller than I thought. The metal part is 110mm long and the hollow profile has outside dimensions slightly under 20mm.
Inside I can see a cell holder for a single AAA battery. And I could see how much damage a single AAA cell can do. It is definitely too colourful in there.  Very bright blue deposits on the interior walls. And crystal growth on the rear end of the PCB.
And here I stopped. I have to figure out how to access the interior. Those fiends have used tiny rivets to hold the front cap in place, and there is nothing to get a grip on them. Maybe I can remove the deformed heads with a riffler file and then push the remainder inside through the plastic cap retaining ears. Not before I have done that can I even assess the extent of the damage.

And single battery operation probably means Ge transistors. And with no documentation, I can only hope that I can still make out most components. If not, as announced, it will have to be a rebuild. But to use all those accessories (gain), get output to the dynamic earphone and have some battery life,  something other than one AAA might be in order. Maybe I could place 2 or 3 button cells opposite the pot/switch towards the rear, if I find little holders with a metallic cap for them. That would make that tearing of the wires unneccessary. But that would mean having a PCB, and getting someone to layout it for me, and soon it will become forbidding in terms or time AND cost.
But given my workload, this is far away. Today I hate my fogging karma. It could have been almost as pristine on the inside as on the exterior, ONCE rewarding me for caring about my tools and gear.
ORCFUCKBLOODSHITMURDERFROG!

[0culus]

The 184 saga continues...sometimes the HF function is showing signs of life but not much. Time to do a deep dive through the manual to try to figure out how it works. I also nearly had an electroboom moment when I accidentally connected the wishbone shaped inductor on the 500MHz board to chassis with my hand when I was moving the thing around. That inductor has +125V on it and it sure woke me up.  Decided it was time to put things away at that point...

[bitseeker]

Agilent 54622D carbon pad restoration

As I said in a previous post, scrubbing / cleaning the carbon pads again with IPA did not help the conductivity, nor did it even remove much of anything. I say "again" because when I got it several years ago I did the same cleaning. That being said, I tested the keys again after cleaning this time and they did not function any better. They all worked but needed to be pressed "hard".

...

Thanks for the update. The suspense was killing me. 

Added to POI.

[bitseeker]

Okies... show of hands.

April 15, I ordered a 10-piece lot of my favorite D-Sun MP1584EN buck converter boards for... stuff. Vendor shows 2-5 week delivery time, but updates in a few days with a Tracking number. Well, FF to this morning, I notice the delivery is now a week past the latest delivery date in the listing, and the tracking still shows as "en route to carrier". So they created a shipment, but either never shipped or more likely are just using that number to satisfy eBay requirements to be able to mark as "SHIPPED" and actually sent it some manner that isn't tracked.

I start a resolution, asking for a refund as I figure after 6 weeks I've been reasonably patient already; the vendor replies crying COVID delays and asking that I wait another 2 weeks. Since I already have a resolution process open, do I give the guy a break, or is 3 weeks late just unreasonable, even with COVID delays...?

mnem
 

I'm still waiting for my orders from China that were placed in March.

[BU508A]

Agilent 54622D carbon pad restoration

As I said in a previous post, scrubbing / cleaning the carbon pads again with IPA did not help the conductivity, nor did it even remove much of anything. I say "again" because when I got it several years ago I did the same cleaning. That being said, I tested the keys again after cleaning this time and they did not function any better. They all worked but needed to be pressed "hard".

...

Thanks for the update. The suspense was killing me. 

Added to POI.

You weren't the only one.   

[mansaxel]

...but I never got the feeling that any progress was made towards the sort of coordination that was needed while the UK's communications infrastructure was being completely reshaped by a bunch of companies all essentially working independently and in competition with each other.

That is exactly the point. We are in a new world, where there is no single GPO or Televerket or Ma Bell to coördinate all the wires. Over here, I know we've got at least some coöperation between the companies on engineer level; I can probably reach people with backbone enable for at least 85% of the eyeball ISP coverage simply by going to IRC. There is a more formal forum with the regulator, ISP's, telcos, various government agencies with acronyms where they coördinate at manager level. It's a small country, this, and we're used to talking in the duck pond.

But, as soon as things are good and you see the prospect of saving some money, leeway is taken.

[xrunner]

Thanks for the update. The suspense was killing me. 

Added to POI.

LOL sorry. Thanks for adding it.

To note: Anyone reading these tips out there and wanting to try them - take account of your skill level and do so at your own risk. Much of the equipment you see in these threads is 10, 20 or more years old and replacement parts cannot easily be obtained. Any number of unforeseen problems can arise by taking them apart and attempting to repair or make them work better. On the other hand - the rewards can be great. Good Luck!

There, now I can rest easier. 

[Saskia]

But given my workload, this is far away. Today I hate my fogging karma. It could have been almost as pristine on the inside as on the exterior, ONCE rewarding me for caring about my tools and gear.
ORCFUCKBLOODSHITMURDERFROG!

@Neomys Sapiens

I propose soaking the PCB in "Essigessenz" and wait for the bubbling to subside. This neutralizes the KOH and basically stops the caustic from eating any further into your PCB.
Next step would be to get the PCB out, put it into an ultrasonic and inspect it under the microscope.
We can do that here (if you want to) and have a closer look at the damage. It may still be repairable, and we could use my microsoldering stuff to redo some traces.

[AVGresponding]

... just a question: Does you omnibus also contain vintage transistors (TO-18) ? I am working on some esoteric oscillator project where I need *old* parts that have not been made using modern production processes.

regards
  Wolfgang

How old, and do they have to be TO-18 package? I have a few, and some TO-5, think I even have some TO-1 germaniums somewhere but I can't find them atm.
I also have a few TO-98 case Japanese 2SC380, 382, and a 2SA495, all 1970s vintage.
The most interesting TO-18 I have (maybe) is a BSX 20, looks to be late 1980s SGS Thompson, Towers guide says it's a 500MHz UHF low current switcher.
Also a few oddball X-09 case from the 1960s, and a lonely TO-66.

If you're interested in any of them, they're yours for the price of the postage.

[Specmaster]

Working on the Black Star 4503 and have just discovered that R39, the input resistor that should be 1K 1W and has always been read as 1K is now reading as 222.5 . I have pulled it from circuit and checked it and it still reads 222.5 so it has short in it somewhere. Lets see if I have one, I know I have .25W one.

Edit
FFS, I must be losing the plot, that resistor is an actual 222 in reality now that I've checked the colour coding, but the schematic and the BOM shows it as a 1K so I'm guessing is selected to keep the overall input resistance the same because of tolerances damm, thought I'd nailed it 

[Wolfgang]

... just a question: Does you omnibus also contain vintage transistors (TO-18) ? I am working on some esoteric oscillator project where I need *old* parts that have not been made using modern production processes.

regards
  Wolfgang

How old, and do they have to be TO-18 package? I have a few, and some TO-5, think I even have some TO-1 germaniums somewhere but I can't find them atm.
I also have a few TO-98 case Japanese 2SC380, 382, and a 2SA495, all 1970s vintage.
The most interesting TO-18 I have (maybe) is a BSX 20, looks to be late 1980s SGS Thompson, Towers guide says it's a 500MHz UHF low current switcher.
Also a few oddball X-09 case from the 1960s, and a lonely TO-66.

If you're interested in any of them, they're yours for the price of the postage.

Thanks a lot for the offer, but I need parts that appear on the NASA parts list. I am builing an USOs that is supposed to be space qualified, so a lot of parts are not even allowed. So for the types, that are 2N2222, 2N2857, 2N2848, 2N3866, ...
really retro, I know. Other parts may be even better, but you know the space buerocrats.

All the best, stay safe !
   Wolfgang

[Zucca]

You should definitely try and specially if you are not ONLY doing python
Mostly  all my colleges have moved to VScode

I like it, pycharm uninstalled. Thanks!

[AVGresponding]

Working on the Black Star 4503 and have just discovered that R39, the input resistor that should be 1K 1W and has always been read as 1K is now reading as 222.5 . I have pulled it from circuit and checked it and it still reads 222.5 so it has short in it somewhere. Lets see if I have one, I know I have .25W one.

Edit
FFS, I must be losing the plot, that resistor is an actual 222 in reality now that I've checked the colour coding, but the schematic and the BOM shows it as a 1K so I'm guessing is selected to keep the overall input resistance the same because of tolerances damm, thought I'd nailed it 

Yeah the discrepancies in the schematic/circuit diagram are a damn nuisance.
I'm guessing the one that's commonly available is the version 1, and they never updated it, just added revision text when they remembered to.
It would be nice if there were a revised schematic/circuit diagram, but I suspect not...

[BU508A]

Thanks a lot for the offer, but I need parts that appear on the NASA parts list. I am builing an USOs that is supposed to be space qualified, so a lot of parts are not even allowed. So for the types, that are 2N2222, 2N2857, 2N2848, 2N3866, ...
really retro, I know. Other parts may be even better, but you know the space buerocrats.

Is it possible, that you could post this parts list here? Just out of curiousity.

Thanks.

[bd139]

Search for "JANTX" on ebay. Sorted. Also broke 

[Cerebus]

I propose soaking the PCB in "Essigessenz" and wait for the bubbling to subside. This neutralizes the KOH and basically stops the caustic from eating any further into your PCB.

If it has been there for any time it won't be Potassium Hydroxide any more, it will almost certainly have converted to Potassium Carbonate by taking up CO₂ from the atmosphere - remember that alkali metal hydroxides are used to make CO₂ scrubbers to remove CO₂ from the atmosphere in rebreathers and spacecraft. It isn't necessary to do anything so aggressive as trying to neutralize it with vinegar. Potassium Carbonate is basically the Potassium version of washing soda (Na₂CO₃) and it ought to wash out quite happily with just water - it's so soluble that it's deliquescent. Adding an acid to the mix could make things worse by attacking things that are susceptible to acid attack that weren't susceptible to attack by bases. In particular, copper is more susceptible to attack by weak acids (e.g. vinegar) than is it to weak alkalis (e.g. K₂CO₃) - I use citric acid to micro-etch copper when making PCBs to promote adhesion of resist films.

[Cerebus]

Search for "JANTX" on ebay. Sorted. Also broke 

I have some NOS JANTX qualified 1N829-1 5ppm/ºC 6.2V zeners that I picked up for a song on eBay a couple of years back. I thought that they'd be useful stock for replacing the same (or less well specified) 6.2V zener references in older test gear. I would not want to have paid full price for them - £7.53 each with a MOQ of 100 on Digikey currently.

[bd139]

Indeed. I own one of them somewhere. No idea where it went. Probably in a bag of other random zeners somewhere!

Edit: random "fuck microsoft". Windows Defender is giving me trouble today falsely flagging newly built and signed MSI packages on desktops but not on their own malware service. Grr. Utter tosser it is.

[Wolfgang]

Thanks a lot for the offer, but I need parts that appear on the NASA parts list. I am builing an USOs that is supposed to be space qualified, so a lot of parts are not even allowed. So for the types, that are 2N2222, 2N2857, 2N2848, 2N3866, ...
really retro, I know. Other parts may be even better, but you know the space buerocrats.

Is it possible, that you could post this parts list here? Just out of curiousity.

Thanks.

Yeah, why not. The link is here:
https://nepp.nasa.gov/npsl/

It also has links to the European and Japanese Space Agency Lists. Dont be surprised that some parts are older than you

[mnementh]

Edit: random "fuck microsoft". Windows Defender is giving me trouble today falsely flagging newly built and signed MSI packages on desktops but not on their own malware service. Grr. Utter tosser it is.

Yeah; when it was still SCEP they were a lot more aggressive about maintaining the definitions files because they'd been caught with their pants down too many times and felt like they had something to prove.

Since they rolled that back into Defender, they've gone back to their old lazy-ass "don't worry about it until enough people bitch about it and it makes the news" approach. The cycle continues... 

mnem
I guess failing false-positive is still better than false-negative...?