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Test Equipment Anonymous (TEA) group therapy thread

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Robert763:

--- Quote from: mansaxel on July 14, 2022, 10:13:05 pm ---
--- Quote from: mnementh on July 14, 2022, 06:10:00 pm ---One of the welding shops I worked at was equipped with a huge ESAB MIG welder bought at auction from a factory closure; they powered it with a war-production motor-generator phase converter that was as big as the welder itself. There are ways... but jeez, the losses...  :o

mnem
 :-/O

--- End quote ---

Mmm, ElektroSvets-AB. Almost as good as Kemppi, who are the masters of both rectifier and inverter welders.

If you want hardcore, look no further than ASEA-Hägglunds; they made motor-generator sets where the motor is three-phase off the mains, and the generator makes the welding current directly. A dream to weld with, I'm told. The inertia in the rotating mass makes for very nice start currents.

--- End quote ---

They used to use big rotary converters to generate 400Hz 3 phase in test labs for aircraft equipment. This was good because it closely replicates the generator (typically 40-150kVA each) on the aircraft. This is particuarly true of impedance, transient response and surge current capability. Now they use solid state converters in the lab. This can cause issues with equipment bein fine in the lab but troublesome on the aircraft. The converter will limit the peak current e.g. at equipmet turn on. They are also less likely to suffer voltage droop or overshoot after a load change than a mechanical generator. While the equipment tests do include transient power variations these are applied with the equipment in steady state condition not response to equipment load variation So in practice to find such issues you might have to use a converter ten time larger that needed to just power the equipment and deliberately degrade it's control loop response.... Or put a big diesel powered AC ground power unit outside the lab....

The latest fancy digital TE is not always best.....

Vince:

--- Quote from: bd139 on July 15, 2022, 08:01:39 am ---
--- Quote from: bd139 on July 15, 2022, 07:01:11 am ---Have opened a case with the seller of the original part now. Their service and communications are terrible so I’m just claiming it back via eBay now. They’re disinterested in dealing with it or sending another part out and are pushing back asking to give it another couple of days after it has been missing for two weeks now on a RM 24h delivery I paid for. So screw them. User test-equip forget it. Shame because they have a lot of tek and HP parts.

--- End quote ---

Replying to self - eBay decided in favour of me almost instantly. Refund on the way. Good job as always  :-+

Discovered recently that due to the chip shortage, the availability of shit Arduino clones is pretty bad and the prices have gone through the roof. Considering buying the last decent "on device programmable microcontroller and electric swiss army knife" at the moment, the BBC Micro  :-DD. That and the user and printer ports give you a 6522 VIA worth of IO to play with, BASIC, assembly support and decent documentation...

--- End quote ---

Wow, a custom vintage Tek PROM programmer, the most interesting thing on TEA since I came here 18 months ago.

I hope you do do it, and share all the details  ! Maybe create a dedicated page on the forum ?

Reminds me of a series of old videos I watched on YT. An old TV program in the UK where they did all sorts of cool stuff with the BBC MIcro.

m k:

--- Quote from: factory on July 14, 2022, 07:41:16 pm ---
--- Quote from: m k on July 14, 2022, 09:17:20 am ---HP 54600 series.

Since picture data goes through 74LS194 with four lines,
I'd check how those values really are.
(page 21/125 of xDevs schematics)

--- End quote ---

The 54615B seems to differ here, can't find any 74LS194 on my mainboard (unless there are parts hidden on the other side), nor the UPD42102G-3 shown for the 54654N (next to the COMBO custom IC).

David

--- End quote ---

Do you have a third set of drawings?
What I got from archive.org was for model 45N.

There A3 System Board side B starts from page 41 and U97 is there.
First component page is Page 05 and there bigger module number 54645-69503 is replaced to smaller 54645-66503.

Schematics Sheet01.1 has a revision history, same with other sheets.
There D-54645-66503-3 has over a year of revisions starting from '96 when component list is indicating that something happened '97.
Maybe it's nothing.

54600A 74LS194 is U37 so equal naming between these modules should put it to side A.
It is outputting half and full brightness from Pixel_data 1 and 3.

COMBO_PAL is also outputting half and full brightness but there are four linebuffer lines.
Pixel_data lines 0 and 1 are right there but 2 and 3 are hiding above LvRAS.
So all four are still there, why leftovers are not dropped, are they leftovers.

BTW,
I "repaired" a front loader clothes washer, UPO something, old local brand, now local somewhere else.
First the drum didn't rotate at all so I took it out of its hole.
After some poking around I tested it again and it started rotating with sort of non-regular chirping sound.
Then suddenly chirping disappeared and now the machine is washing like a new, but without spinning.
Earlier spinning tests had few sort of inrush moments where speed tried to max from zero right away.
Chirping was also coming from somewhere under the drum and clearly away from the center.

First I thought the problem was a control panel chip with a missing piece.
Had to get more light and googles and so the chip was actually intact but partially covered with black dust, like old TV HV parts and one of its eight legs were missing since the beginning.
The chip was LNK304GN, a regulator part for non-isolated situations and circuit close to manufacturers example.
Output was 16.6V so more regulators later but pretty easily down from 300V.

Generally quite a bugger was this machine.
Control panel was easily available but no back plate, solid plate over 3 sides, clearly a dropped in drum and stuff.
If this is a norm today no wonder EU did its repair law.
On the other hand, if retail price is <300€, smallest ones <200€, and imported, here over the sea and 1/5 VAT, it must be a quick assembly with minimal raw materials.

bd139:

--- Quote from: Vince on July 15, 2022, 10:28:21 am ---
--- Quote from: bd139 on July 15, 2022, 08:01:39 am ---
--- Quote from: bd139 on July 15, 2022, 07:01:11 am ---Have opened a case with the seller of the original part now. Their service and communications are terrible so I’m just claiming it back via eBay now. They’re disinterested in dealing with it or sending another part out and are pushing back asking to give it another couple of days after it has been missing for two weeks now on a RM 24h delivery I paid for. So screw them. User test-equip forget it. Shame because they have a lot of tek and HP parts.

--- End quote ---

Replying to self - eBay decided in favour of me almost instantly. Refund on the way. Good job as always  :-+

Discovered recently that due to the chip shortage, the availability of shit Arduino clones is pretty bad and the prices have gone through the roof. Considering buying the last decent "on device programmable microcontroller and electric swiss army knife" at the moment, the BBC Micro  :-DD. That and the user and printer ports give you a 6522 VIA worth of IO to play with, BASIC, assembly support and decent documentation...

--- End quote ---

Wow, a custom vintage Tek PROM programmer, the most interesting thing on TEA since I came here 18 months ago.

I hope you do do it, and share all the details  ! Maybe create a dedicated page on the forum ?

Reminds me of a series of old videos I watched on YT. An old TV program in the UK where they did all sorts of cool stuff with the BBC MIcro.

--- End quote ---

I will create a thread for it if I get anywhere. I'm putting it off for a little bit until I've moved as all the kit is packed away for it at the moment so not much point in getting it all out as I'm going to have to put it all away after  :-//

BBC micro is fairly easy route for that sort of task. I used mine for all sorts of nasty hacks back in the day.

This is a very fine example of what you can do...

Neomys Sapiens:

--- Quote from: mansaxel on July 15, 2022, 07:55:58 am ---Trip report:

To escape the the heat, visit fortifications.

To manage wine buying habits, install reinforced springs on your car.

Accidental TE:

From Fort d'Uxegney just west of Epinal. Meter is from the original 1914 installation of "Groupes Electrogènes" in the fort.

Today, having visited the immaculate condition fort above, we're going to teach the realities of war, with a visit to forts Douaumont and Vaux, along with the actual boneyard,  outside Verdun.

--- End quote ---
After having been to Munster, you should consider going to Saumur:

https://www.museedesblindes.fr/

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