Time Electronics 9814 DC calibrator

[VintageTest]

Hi everyone,

I can't remember if I've asked you all this or not, so here goes! I repair vintage tech and have both an old Fluke760A and a more modern Time Electronics 9814. I bought the 9814 to replace the Fluke, as it's smaller, lighter, more accurate etc, etc. However, I had tested it when I bought it at the beginning of the year and everything was hunky-dory then. I left it on the lab floor and kicked it over one day - it was standing on end. Now it seems to be an order of 1000 times too low - 10V measures as 10mV! Time are no help at all, with the 'it's obsolete' excuse, but sent me the 'Technical Manual' for the MK3 version (not the one I have), which has no schematics. There's little , if any, info on the 'net, although I did find a teardown on a 9823 - which is a different beast, but contains broadly similar cards - except the reference board. So . . . I was hoping that just mayba someone might have a schematic for this old calibrator. I've dismantled it and checked for anything which could be shock damaged or loose, but nothing. The power supplies are fairly primitive and good, the processor is working ok as well. Any help would be appreciated!

Cheers all,
Mel

[doktor pyta]

It should be simplified version of this calibrator: https://xdevs.com/fix/te9823/
Manuals in the same article.

[VintageTest]

Thanks, I have that, but as I said, the reference card is quite different, although the D/A card seems similar.

Cheers,
Mel

[chekhov]

Maybe some IC decided to jump out of its socket ? (or similar mechanical issue with connections)

[NyquistNoise]

Hi Mel,

I've worked on quite a bit of TE gear, but never the one you're attempting to repair. I've repaired a 9823 so am familiar with the construction style. I've had a similar problem with a TE unit which was a stuck attenuator relay (out by a multiple of 10 issue). It might be worth going around and just checking any relays are switching correctly and not seized.
Please do post images of the voltage standards guts - always interesting to see what makes them tick. I assume as with most Time Electronics gear the reference is a plan old diode in a potted ref box?
Also if possible please do upload the technical manual, we can see if it hints at any clues to your fault!