Datron 1281 Meter Repair Help

[starjohn]

I am working on a Datron 1281 meter.
DC voltage calibration at 10v functions ok, but the Internal source calibration failed.
This Meter has the following errors after Internal source calibration.
Error codes:
2202 1KV    Range zero magnitude test   (P028).
2192 100V  Range zero magnitude test   (P021).
2162 10V    Range zero magnitude test   (P006).

What would cause these errors?
Is there anyone that has experience in repairing these instruments?

[jjohnson]

I also have a Datron with the same issues to include error codes 2222 and 2224. I was hoping you may have found a solution to your first three. What I have found in looking through my unit is that at the lower ranges 10v and below i have some random spuratic noise on my guard in certain areas of the board not sure if it suppose to be like that but it seems to come from the bootstrap area and cant seem to pin point the bad component if you can help please let me know.

[pelule]

I am working on a Datron 1281 meter.
DC voltage calibration at 10v functions ok, but the Internal source calibration failed.
This Meter has the following errors after Internal source calibration.

How did you do the internal source calibration?

[Krampmeier]

You can start the internal source calibration by entering the EXT CAL menu and selecting QUIT. The meter will then ask if you want to trigger the internal source cal or quit. After that, you can set the cal due date.