Test Equipment Anonymous (TEA) group therapy thread

[pcprogrammer]

You know what you have to do......

Get some wax and give yourself a brazillian! It's the only way to properly test that it's working right. haha

As long as he does not post those pictures

[SeanB]

You will be easily able to find a standard candle on a clear night, just look with a telescope at distant galaxies for a type 1A supernova, which occur about once a week  in our galaxy alone. They all have the same brightness, and are used as a standard candle to measure distance.

As to those tantalum capacitors, the price on them from Vishay is POA, especially the higher values. Still got some 1200uF 16V ones around, plus a good number of 10uF 25V ones, all in the glass frit seal soldered package, they are almost impossible to have fail, unless you apply reverse voltage with enough current. Then they make fairly good bullets, which is what we did with the rubber seal ones (which do fail with time alone), using the bench vice and the power supply I built into the test bench. anything from 0-25VDC (limited by the 28VDC input from the power board on the wall) and capable of 40A, limited by the wire in the wall dropping around 20V then.

[m k]

You know what you have to do......

Get some wax and give yourself a brazillian! It's the only way to properly test that it's working right. haha

As long as he does not post those pictures

Are you a naturalist?

[Black Phoenix]

You know what you have to do......

Get some wax and give yourself a brazillian! It's the only way to properly test that it's working right. haha

As long as he does not post those pictures

Please no... I want to sleep tonight and I don't need nightmares...

[TERRA Operative]

For those with a Tektronix TM502A mainframe, I just uploaded a high quality scan I made to Tekwiki. (It's the 070-6502-00 manual)
If you print it duplex with size set to 'Fit' and Orientation set to 'Auto', it should print correctly (foldouts will be scaled and rotated to fit the page of course).

https://w140.com/tekwiki/wiki/TM502A

[pcprogrammer]

You know what you have to do......

Get some wax and give yourself a brazillian! It's the only way to properly test that it's working right. haha

As long as he does not post those pictures

Are you a naturalist?

I used to be when I was young and without wrinkles, Now I would need to iron first

But for some electronics and TE talk. I'm back on the FPGA and getting closer to the end of reverse engineering the FNIRSI 1013D scope its FPGA. Struggling a bit with the internal clock routing. Lots of data to process.

[Vince]

Vince, is that piece of junk using the X2 capacitor as a capacitive dropper? If it is, check it's not dropped in value and causing low voltage problems with the power supply. It's very hard to tell from the mess of wiring inside.
This type of circuit is very common these days, to avoid using expensive copper/iron lumps for the power supply.

Also check the electrolytic cap, could be dried out from being stuck underneath a heat source.

David

Yep I am now aware that these freaking X2 dropper caps can fail, since I had them go bad in no less than 3 appliances in the last 12 months.... I used to think naively "it's a film cap, it never fails"... but yes they do in this type of application at least ! 
I quite liked the video Dave Jones did on this very subject, which cleared thigns out... before, I was a bit confused by this cap/zener arrangement, wondering how it was supposed to work...

Well now that I am aware of it, I now go straight at them in case of power supply problems....

Next step was to test what this heater was doing so... despite the short wires, I managed to put the thing together in a way that the bowl would be sitting upright, sitting safely enough on its base, while at the same time having the PCB fully sticking out so I could probe whatever I wanted to probe, like the power supply to begin with.

Then I poured a couple glasses of water inside the bowl, making it half full. The red indicator light would tell me what the control loop was doing, and then I put a thermometer inside the bowl to see what was going on exactly. I don't even have thermometer but.... BU sent me one the other day when I was working on my fridge timer ! Thank you BU, see I make use of it today, glad I have it !! 
That said now I know the PT100/1000 probes that my DMM uses, are so cheap... I shall soon get one. Might also get one of those cheap ass IR thermometer guns, quite handy they are.

Then I spent probably 2 or 3 hours (time flies...), testing that thing for various pot inputs, watching patiently water warming up, cooling down, regulating... and well, looks to be working just fine to me !
So I think it's was indeed just a mechanical problem, the plastic arrangement holding the pot in place, being in a million pieces.
So I cleaned the area with acetone, then hot-glued the pot in place.... yes, it's the best this piece of filthy junk deserves, if even that ! 
Result : pot is held in place just fine ! I have to say I am liking hot snot more and more ! 

So I put it all back together, and hopefully my friend can take this horrible, disgusting thing away from me real soon !

[pcprogrammer]

Yeah that is the downside of knowing electronics. All your friends come to you to get things fixed

[Neomys Sapiens]

.
.
I've prepared a little experiment:
Some time ago I've built a little gadget to reform capacitors and measure the leakage current.
.
.

Is that a HERMETIC 700µF capacitor?
 
If so, whoa!

I've bought them as military grade wet tantalum capacitors.
Here is my little collection. The ERO ones are multipack tantalum capacitors, they just share the same storage box as the others.

Are they still available or was it an one-off?

[McBryce]

Do you have a candle to check the calibration? 

What about this hackable candle simulator:
https://youtu.be/LocrjlooIT4

Not cheap. Friend of mine has one.
At garden parties, in the evening kids up to 15 try to put a hand or finger into the flame. It's that well made. Live better than in this video.
(The PCB is not covered by any casing, so it is easily accessible for TE probes.)

They cost 510 Euro for one candle.
Can be bought here: https://shop.ingo-maurer.com/en/My-New-Flame-USB/3331131

To put it mildly, that's taking the piss.

McBryce.

[BU508A]

I've bought them as military grade wet tantalum capacitors.
Here is my little collection. The ERO ones are multipack tantalum capacitors, they just share the same storage box as the others.

Are they still available or was it an one-off?

Sadly, they are all gone. I've bought them in 2017 just by pure luck, because I was looking for some input capacitors for a low noise amplifier (0.1 - 10Hz) which is still in my project queue. I do still have some of the badges from the Bundeswehr which marked them as spare parts. Some of them were used ones, pulled from some gear, not sure about their origin.

[factory]

I'll just leave this here, still haven't got the milling machine setup for modifying the replacement side frame.





P.S. also need to take better picture. 

David

[Vince]

Oh boy these old HP handles really just kept breaking, they made them out of glass FFS ! 

[Neomys Sapiens]

The story of the Testovent heated-wire anemometer ended on the scrap heap.
After the mechanical problem with the instrument's adjusting screw was resolved, the functional test gave a negative result. For a first try, I left the telescopic probe, which does not retract completely, undisturbed.
Reassembled, battery fitted, battery test ok...and that was it. Electrical zeroing not possible and resulting in erratic indications. The moving-coil indicator itself is working properly.
Inside I found 4 LM358 and some transistors and diodes. Visually, no suspicious parts or connections could be seen.
I exchanged the OPAs, which are in sockets, and did a quick in-circuit test of the other semiconductors. Result: just the same.
I then looked at the probe in order to decide whether I should try further. Upon removal of the plastic bushing at the cable entry broken parts of a copper spring came out, which did not improve but worsen the blockage.
Already having found out that Testo won't or can't help, this is an ex-anemometer. I got a cheap chinese impeller-type anemometer to perform the test at work and set the Testovent aside for possible parts reclamation.
I have a multitude of more pressing and interesting projects.

Next week (I'm on vacation) the young lady studying physics is visiting again. Given that she also has some other activities planned in the region, we have quite a pensum of work set out for us. Some practical test and measurement, building  a quick and cheap power supply for her out of the carcass of a Voltcraft PS, introducing her to PSPICE.... while keeping it not too stressful, will be just enough.
Also looking forward at the Weinheim UKW-Tagung with the (hopefully well-stocked) Ham fleamarket on Saturday.

[Vince]

Yeah that is the downside of knowing electronics. All your friends come to you to get things fixed

Yeah I keep quiet now not to attract junk like a magnet. I only do it for good friends that help me out for other stuff... it's win-win. I would not work on such junk for some random guy, especially since of course he would expect the repair to be free as always ! 

Anyway, same friend passed me ANOTHER piece of junk to look at ! Here it is !

This one is more interesting (and much cleaner !).. a little Bosch consumer grade "cube" laser ! 
I sure could do with a laser.  However I doubt I can revive this one... but if I can, he said I can keep it 

Friend said it stopped working after too much time spent with the batteries (a couple AAA) still in it, in his damp garage.

I just cracked the cube open, and removed the PCB. It's covered with corrosion all over the place on both sides. I am not sure I want to bother... he said he bought it for only 50 Euros tops back then...

However just for fun I might work on it just this evening, as a little " revival " challenge !  I want to see if I can see that laser come back to life and illuminate the room !

ALSO... there is a foot print for an 8 pin 0.1" header right next to the MCU, and the silk screen next to it says two things :

1) " SWIM "... might be why it's all corroded ! 

2) " UART "  AH !!!!!  I want to revive this thing just to see if the MCU spits something out on the UART, and what it is ! 

That's more fun than a gross wax heater for sure...

[Neomys Sapiens]

After I lost a bid on eBay for this document last week (sold for 25.-€!), a quick web search yielded a result on booklooker for only 6.90 including postage. Bought and received. Condition flawless.
When I'm back at work, I will scan it and make it available. But at 56 pages this will probably take several weeks.

[Robert763]

I'm going on a TE road trip tomorrow.
Telford hamfest in the morning, a stop near Manchester to drop of a test lead then up to Otley in Yorkshire to pick up a coule of R&S "collection only" ebay purchases.  Over 400 miles round trip 

[capt bullshot]

...
1) " SWIM "... might be why it's all corroded ! 

2) " UART "  AH !!!!!  I want to revive this thing just to see if the MCU spits something out on the UART, and what it is ! 

SWIM is the debug port of STM8 MCUs. You can see one of these on the board. But what I don't get, this thing is just a laser putting out crossed lines - why in heck do they need an MCU?
Apparently it does some kind of self-leveling, but this feature looks mechanical, not electronic. So is it just an overcomplicated ON/OFF switch?

[Squarewave]

I'm going on a TE road trip tomorrow.
Telford hamfest in the morning, a stop near Manchester to drop of a test lead then up to Otley in Yorkshire to pick up a coule of R&S "collection only" ebay purchases.  Over 400 miles round trip 

400 miles?! THAT is dedication!

[Vince]

...
1) " SWIM "... might be why it's all corroded ! 
2) " UART "  AH !!!!!  I want to revive this thing just to see if the MCU spits something out on the UART, and what it is ! 

SWIM is the debug port of STM8 MCUs. You can see one of these on the board.

Oh thanks, interesting ! You learn a little something every day... don't know squat about  STM MCUs...

But what I don't get, this thing is just a laser putting out crossed lines - why in heck do they need an MCU?
Apparently it does some kind of self-leveling, but this feature looks mechanical, not electronic. So is it just an overcomplicated ON/OFF switch?

The self leveling is mechanical using a pendulum yes, but it has a limited range of course. In this case 4 degrees. If more than that, the pendulum can't go any farther. The MCU detects this condition, and to signal the user that the self leveling is not possible any more, it blinks the laser beam slowly.

[factory]

Oh boy these old HP handles really just kept breaking, they made them out of glass FFS ! 

Thin cross section of die cast zinc/alu alloy versus crap packaging (I blame people copying amazon) and/or shipping gorilla(s) unfortunately. 

See this almost three year old post for the replacement sideframe. https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg2719034/#msg2719034

A lot has happened since then....

The milling machine & another lathe that were at my Grandads place, are now in my Dads workshop, unfortunately some of my TE & other stuff, is all around both machine tools & we can't get to either to actually use them. I see no end to this problem yet, as the storeroom is pretty much full (they have no larger rooms available) and I'm struggling to find an affordable property, with enough space for the TE. 

David

[AVGresponding]

Oh boy these old HP handles really just kept breaking, they made them out of glass FFS ! 

Thin cross section of die cast zinc/alu alloy versus crap packaging (I blame people copying amazon) and/or shipping gorilla(s) unfortunately. 

See this almost three year old post for the replacement sideframe. https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg2719034/#msg2719034

A lot has happened since then....

The milling machine & another lathe that were at my Grandads place, are now in my Dads workshop, unfortunately some of my TE & other stuff, is all around both machine tools & we can't get to either to actually use them. I see no end to this problem yet, as the storeroom is pretty much full (they have no larger rooms available) and I'm struggling to find an affordable property, with enough space for the TE. 

David

Ironically they'd be a lot stronger if they were made out of glass. GRP, at any rate. The repairs I've done using that have taken a lot of abuse to come apart.

[Vince]

Oh boy these old HP handles really just kept breaking, they made them out of glass FFS ! 

Thin cross section of die cast zinc/alu alloy versus crap packaging (I blame people copying amazon) and/or shipping gorilla(s) unfortunately. 

See this almost three year old post for the replacement sideframe. https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg2719034/#msg2719034

A lot has happened since then....

The milling machine & another lathe that were at my Grandads place, are now in my Dads workshop, unfortunately some of my TE & other stuff, is all around both machine tools & we can't get to either to actually use them. I see no end to this problem yet, as the storeroom is pretty much full (they have no larger rooms available) and I'm struggling to find an affordable property, with enough space for the TE. 

David

Thanks, I understand now.... was not familiar with the HP way of doing things, didn't know the handles were an integral part of the sides 

Lucky you could find spare sides with that seller.

As for milling, Robert just got his fancy shiny new mini milling machine. Might be good enough for what you have to do ?
Maybe you can subcontract the job to him, maybe he can give you a TEA discount on his usual 200 quid hourly labour rate ?! 

[factory]

Thanks, I understand now.... was not familiar with the HP way of doing things, didn't know the handles were an integral part of the sides 

Lucky you could find spare sides with that seller.

As for milling, Robert just got his fancy shiny new mini milling machine. Might be good enough for what you have to do ?
Maybe you can subcontract the job to him, maybe he can give you a TEA discount on his usual 200 quid hourly labour rate ?! 

I was very lucky to find some at the time, most sellers that scrap old TE for parts never even think to offer them, I know this as I've messaged several sellers trying to obtain a sideframe to fit a 140/141 series, I was always too late and the case/frame already thrown out.

David

[factory]

In other news, I found the (almost complete) prototype bodge I was making to replace the HP 1820-0092 display decoder/driver IC. It's a 74141 with a TI 74F00 (wired as inverters) stuck on the back, to invert the negative BCD input used by the original IC, here it is now finished.




Testing was done using the board I made, this is a BCD switch with 7404, to invert the positive BCD to negative BCD, the 6237B was used for the +5V and the 6290B provided the +170V.





The BCD switch only does 0 to 9, to test the blanking I abused one of the dead (salvaged parts) 7404 ICs  , soldered four pins together, may have to find another switch in the future & replace the 10 position one.



I'm happy to say the prototype works fine. 

This leaves me with one question, why do the salvaged 1820-0215 ICs not work, well I suspect they are a different BCD code or pinout. I've ordered a manual from Artek, that will hopefully answer this, the Agilent one is unreadable crap as usual.

David