[volt-nuts] Datron 1281 Repair Help

[jjohnson]

Михаил <timka2k at ...> writes:

> 
> M202 (DG211) switchs, pins 6-8 and 1-3.
> 
> Friday, March 21, 2014, 2:45:46 PM, you wrote:
> sun> I am working on a Datron 1281 meter.
> sun> DC voltage calibration at 10v functions ok, but the Internal source 
> sun> calibration failed.
> sun> This Meter has the following errors after Internal Source Calibration.
> sun> Error codes:
> sun> 2202 1KV    Range zero magnitude test   (P028).
> sun> 2192 100V  Range zero magnitude test   (P021).
> sun> 2162 10V    Range zero magnitude test   (P006).
> sun> What would cause these errors?
> 
> 


I have the same issue and prior to seeing this blog i checked the m202 dg11 
switchs and did not find an issue. What i did see was noise on the guard 
around that line which goes to the non-inverting side of the dc amp, where 
that noise is coming from possibly the bootstrap i am not 100% or i would have 
fixed it. But it seems like this is a common issue this is the second post i 
have found on this issue which makes me believe it not a cold solder issue. 
Ive checked most caps in power supply and dc board if you have any other 
possibilities please let me know.