Electronics > Metrology

Data Precision 8200 calibrator - repair and other fun stuff

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branadic:
I today received some DIP-TO99-adapters and desoldered the components on the board (Z6, Z14, Z19, C19).
Z6 was an AD517, while Z14 was an opamp marked AD40932, same as Z19, except it had a plastic cap/cover and was potted inside with some sort of silicone. When I removed the silicone I found that the leads on all pins were extended with 10R (brown, black, black, gold) carbon composite resistors, probably to reduce heat flow?, which I found pretty interesting. The three OP177 are now in place, we will see how that turns out.

-branadic-

branadic:
After some zero point adjustments, I still use the original 50k at the offset trim pins of the opamps, I took some noise measurement data on the 10 V ouput. It seems like there is an improvement.  :-+

rms = 388 nV
std = 387 nV
pp = 2.7 µV

rms = 500 nV
std = 500 nV
pp = 3.2 µV

rms = 401 nV
std = 401 nV
pp = 2.8 µV

rms = 382 nV
std = 382 nV
pp = 2.9 µV

rms = 399 nV
std = 399 nV
pp = 2.5 µV

-branadic-

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