DEC AXV11-C analog board

[Douglas Taylor]

I have one of these and would like to use it, however it appears to only 
partially work.  Here is what I have found that works and what doesn't:

1. CSR and DBR are present and operational.

2. Jumpers set to 'factory'.

3. D/A portion works, can deposit codes in ODT and see voltages out on 
DAC pins that change depending on the octal value deposited in CSR+4 or +6.

4. A/D portion returns full scale code, either 3777 (2's compliment) or 
7777 (offset binary) whether in the input is open or shorted to gnd.

I think the problem is that the A/D inputs are not exactly protected and 
damage has occurred to this portion in the past.

Does anyone have any info on the A/D module?  Who made it?  Can you open 
it up?  Does XXDP have a test for this?

Doug