Test Equipment Anonymous (TEA) group therapy thread

[SeanB]

Just bought an old bridge  ... Japanese kind  ... (more details attached below)

Snap, got one a while ago, and ordered recently some 2AA to D cell adaptors for it ( 5 pack, I need one for an AVO8 and a 5 pack was cheaper than the single ones) so I can remove the brass shims that currently allows 4 C cells to power it. Accurate, had to make a copper plate shorting shim to zero it properly, the meter can actually measure under 20 milliohms of the shorting shunt, let alone the leads i first tried.

[bd139]

I was surprised to find that the power supply in my HP54602 was made by Yokogawa

[BravoV]

Snap, got one a while ago, and ordered recently some 2AA to D cell adaptors for it ( 5 pack, I need one for an AVO8 and a 5 pack was cheaper than the single ones) so I can remove the brass shims that currently allows 4 C cells to power it.

Thanks, good idea. 

Going to order these AA to D adaptors and a set of four of LSD Eneloop AAs.

SeanB, what kind of battery do you put in yours ? As I'm a militant anti alkaline cell especially in T&M equipments. 

Will the nominal 1 to 1.1 volt NiMh cell times four cells voltage enough to power it ?

Accurate, had to make a copper plate shorting shim to zero it properly, the meter can actually measure under 20 milliohms of the shorting shunt, let alone the leads i first tried.

As its sealed, but as photos mine is quite old, does it need some sort of maintenance, especially at the mechanical switch ? I haven't tear it down for inspection yet.

[URI]

I was surprised to find that the power supply in my HP54602 was made by Yokogawa

Yokogawa and Hewlett Packard weren't competitors in some fields:

My HP 4263A LCR Meter has a sticker "Yokogawa-Hewlett-Packard" on its back panel.   

Wikipedia:
"HP and Yokogawa formed a joint venture (Yokogawa-Hewlett-Packard) in 1963 to market HP products in Japan.[13] HP bought Yokogawa Electric's share of Hewlett-Packard Japan in 1999."   

[URI]

I was surprised to find that the power supply in my HP54602 was made by Yokogawa

BTW: How about your repair of the HP54602?

[bd139]

Getting there. Found out that the dead channels are due to the offset summing amplifier knocking the traces out of the input range of the ADC rather than anything nasty like blown up ADCs or hold ICs. Might just be a fluffed DAC or opamp after it. I haven’t dug further yet. Took a while to get that far. Likely something as trivial as an open resistor or duff LM324.

Annoyingly a lot of work has been done because some chump clearly dropped it. I had to rework half of the front panel and some diodes as the former had cracked and the latter had exploded taking a big chunk of the board out. The panel is entirely working now though albeit propped up with kynar, some non SMD 1n4148’s and kapton tape 

All the self tests are now passing which is good though.

Going pretty well 

[Specmaster]

Getting there. Found out that the dead channels are due to the offset summing amplifier knocking the traces out of the input range of the ADC rather than anything nasty like blown up ADCs or hold ICs. Might just be a fluffed DAC or opamp after it. I haven’t dug further yet. Took a while to get that far. Likely something as trivial as an open resistor or duff LM324.

Annoyingly a lot of work has been done because some chump clearly dropped it. I had to rework half of the front panel and some diodes as the former had cracked and the latter had exploded taking a big chunk of the board out. The panel is entirely working now though albeit propped up with kynar, some non SMD 1n4148’s and kapton tape 

All the self tests are now passing which is good though.

Going pretty well 

Great news, will the board repair be permanent or will you have to look for a donor one?

[bd139]

Permanent. Fix will be durable.

[URI]

All the self tests are now passing which is good though.

Going pretty well 

Congrats! I hope the faults still in there won't be too bad.   
I'm seeing forward to reading future posts in that thread.

[tggzzz]

There is literally bugger all happening on ebay. Diddly squat. It's terribly boring.

There's more to life than fleabay. There are real life flea markets such as the hamfest in Didcot next Sunday. Make a day out of it at the Pendon Museum - that has the advantage of demonstrating what real obsessive attention to detail is like

https://www.g3pia.net/radio-electronics-rally/
https://www.pendonmuseum.com/

Very tempting. I will spend the next week persuading myself to go to that. Didcot isn’t a terrible trek from here either.

Did you get there? I did, and found it to be much larger than I expected, at least the same table area as at Kempton. As a bonus, the "big new" sales organisations weren't there, so it was almost entirely a good old-fashioned flea market.

I restrained myself to buying a ridiculous quantity of wire-ended neon bulbs, a big bag of bigger-than-normal resistors, six 50ohm SMA terminators, and a Tek 475 which sort-of-works but has 2 6062B probes, the service manual and a front cover.

Total cost including entry was £29
But excluding car costs and visit to the Swindon "outlet" shopping centre

[bd139]

Unfortunately not. Was pretty exhausted after yesterday (5AM start and 1AM bedtime driving wife in and out of London to stations) so crashed until far too late today to bother. Plus my eldest was out and my wife was unconscious so baby sitting was required. Ended up playing with Lego instead so I'm not complaining

That's is however a pretty good haul for the day! Can't complain at that. Nice work. You're lucky I didn't go or you'd have to have fought me for that 475 . Very good deal that.

I however did a mini spend up on Aliexpress in lieu: one dual valve 6J1 preamplifier kit (this will never be an audio preamp but a 1W-ish CW transmitter), one HT/filament transformer, a mini tesla coil kit and some 2.1mm DC to screw terminal connectors. Down £20 which was an acceptable compromise for not going. Although three of the items may attempt to kill me.

[Specmaster]

There is literally bugger all happening on ebay. Diddly squat. It's terribly boring.

There's more to life than fleabay. There are real life flea markets such as the hamfest in Didcot next Sunday. Make a day out of it at the Pendon Museum - that has the advantage of demonstrating what real obsessive attention to detail is like

https://www.g3pia.net/radio-electronics-rally/
https://www.pendonmuseum.com/

Very tempting. I will spend the next week persuading myself to go to that. Didcot isn’t a terrible trek from here either.

Did you get there? I did, and found it to be much larger than I expected, at least the same table area as at Kempton. As a bonus, the "big new" sales organisations weren't there, so it was almost entirely a good old-fashioned flea market.

I restrained myself to buying a ridiculous quantity of wire-ended neon bulbs, a big bag of bigger-than-normal resistors, six 50ohm SMA terminators, and a Tek 475 which sort-of-works but has 2 6062B probes, the service manual and a front cover.

Total cost including entry was £29
But excluding car costs and visit to the Swindon "outlet" shopping centre

Wow that sounds pretty reasonable, even with the annual subscription on top I reckon you did well there 

[tggzzz]

Ended up playing with Lego instead so I'm not complaining

That's a most excellent use of your time; cherish it while it lasts!

That's is however a pretty good haul for the day! Can't complain at that. Nice work. You're lucky I didn't go or you'd have to have fought me for that 475 . Very good deal that.

You could have had the working rack mount Tek 7603; I couldn't be bothered because the timebase plugin was only a single timebase, and I don't have any extender cables. (Well, I do, but only for a 500 series)

You could also have had many naked nixies, or 4 nixies plus drivers on a PCB. I passed since the seller felt that was worth £50; it may be, but not to me

[bd139]

Not sure I could have been bothered with the ear ache of a 7603 rack mount. They’re quite a bit deeper than the standalone units if I remember.

I’d pass on that for nixies. It’s much cheaper buying some old knackered Heathkit or Advance gear and nicking them out of that if that’s your thing. May be frowned upon but the gear was usually substandard anyway

[mnementh]

Getting there. Found out that the dead channels are due to the offset summing amplifier knocking the traces out of the input range of the ADC rather than anything nasty like blown up ADCs or hold ICs. Might just be a fluffed DAC or opamp after it. I haven’t dug further yet. Took a while to get that far. Likely something as trivial as an open resistor or duff LM324.

Annoyingly a lot of work has been done because some chump clearly dropped it. I had to rework half of the front panel and some diodes as the former had cracked and the latter had exploded taking a big chunk of the board out. The panel is entirely working now though albeit propped up with kynar, some non SMD 1n4148’s and kapton tape 

All the self tests are now passing which is good though.

Going pretty well 

Mmmhmmm... sounds like you did it the hard way; with epoxy and foil. I've used the Cicuitmedic kits before; their dry resin technique is pretty awesome and OE durable. I was lucky enough to have the company pay for it when I was doing rework; I just wish I'd had the foresight to nick a few leftover circuit frames and eyelets before I left, as all their product are frightfully expensive.

I wonder if any of the China-direct manufacturers have glommed onto that idea yet and I can find usable supplies at slightly less than "an arm and a leg and your firstborn" prices.



Onto my T12 project...


Well, my 1.3" OLEDs arrived; unfortunately, while I THOUGHT I was buying one 1.3" OLED with SSH1106 controller and one 1.3" OLED with SSD1306, what arrived was two of the same exact SSH1106 1.3" OLED display from two different listings. At first I thought it was a parts pick error; but after reviewing the listings I confirmed it was my own damned fault. 

Anyways...




As you can see here, the larger white OLED does appear slightly brighter, and I do kindof like having it all the same color.





However, once the smoked lens is placed over the OLEDs, the perceived brightness difference is pretty minimal. Usability is a little better simply due to larger pixels and more total light emission. But the SSH1106 is of course the wrong controller for the firmware in this T12 unit,  and the pixel addressing is wrong, offsetting the first few columns to the wrong side of the display. I could probably modify the firmware to relocate the errant pixels; but my Kung-fu is weak and I can't be arsed. I'd much rather just throw a few more $$$ at the question and have an excuse for stockpiling some OLEDs. 

I'm shopping for a new SSD1306 OLED, but it appears there must some considerable demand for these right now, as one of them in the 1.3" size costs as much as both of these HS1106 OLEDs did.  Of course. 

I'll let y'all know what develops once the SSD1306 OLED is ordered and arrives.

Cheers,


mnem
Are your OLEDs REALLY organic?!?

[Neomys Sapiens]

For those Nixie-Fans among us: there is a moderately priced Keithley160  on Ebay DE.
https://www.ebay.de/itm/Nixie-Tischmultimeter-Keithley-160-mit-original-Service-Manual/253413525681
Due 13. Feb. 2018 19:13:50 MEZ

[URI]

Jippie!

I managed to compile gpib 4.1.0 on my raspberry pi3 successfully.
Connected my USB-to-GPIB-adaptor (easy, w/o firmware to be loaded: NI GPIB-USB-HS) to the raspi, ran gpib-config and tadaa:

pi@raspberrypi:/usr/local/src/linux-gpib/examples $ ibterm -m 0 -d 6
Attempting to open /dev/gpib0
pad = 6, sad = 0, timeout = 10, send_eoi = 1, eos_mode = 0x0000
ibterm>id?
PM25350 S04
ibterm>
TDC     +023.20E+00

For a simple test: measuring temperature using a PT100 sensor on my Philips PM 2535 multimeter.   

But that's just the beginning.
I've got a Keithley KUSB-488 USB-to-GPIB-adaptor that I want to use side-by-side with the NI GPIB-USB-HS (just too many devices for one GPIB-subsystem). Could turn out to be a real text adventure on the command line for me.   

That will be the basis for doing automatic or long-term measurements.
Will have to dig into Python for that and I'm not a programmer or software engineer. I'll be facing a very steep learning curve..   

[mnementh]

mnem
*Un-programmer*

[bd139]

Been programming python for 20 years.

The xkcd that will be released in about a decade as a successor to the above depicts someone plummeting to earth due to having to do a git merge on two fucked up branches of python indentation from two developers who were on a death march and have both left the company.

[Specmaster]

Been programming python for 20 years.

The xkcd that will be released in about a decade as a successor to the above depicts someone plummeting to earth due to having to do a git merge on two fucked up branches of python indentation from two developers who were on a death march and have both left the company.

[beanflying]

I think my head would explode if I tried adding Python to it so many programming languages already being forgotten in it now 

[Mr. Scram]

Been programming python for 20 years.

The xkcd that will be released in about a decade as a successor to the above depicts someone plummeting to earth due to having to do a git merge on two fucked up branches of python indentation from two developers who were on a death march and have both left the company.

Death March is next month, no?

[beanflying]

I like this 

[mnementh]

Been programming python for 20 years.

The xkcd that will be released in about a decade as a successor to the above depicts someone plummeting to earth due to having to do a git merge on two fucked up branches of python indentation from two developers who were on a death march and have both left the company.

And you know this because you typed "Import TARDIS" in your editor after licking a number of colorful frogs, no doubt...


mnem
Seriously... I'm programming-defective, in the same way I'm math-defective. If it weren't for my TI-82, I'd have never graduated.

[neo]

My 0-12 just stopped displaying a trace. Nothing catastrophic happened and the rear of the CRT still lights up, worked just fine last night.
Exact coarse of events, crt was loose and so it rotated when i moved it.
I open it and very carefully rotated it back.
I take extreme caution and tighten the clamp.
Quick test, still works and is even.
Back in the case it goes and to bed i went.
No trace this morning. 

Anyone got any hints or ideas? I hope i didn't screw damage it.