DEC AXV11-C analog board

[Douglas Taylor]

Yes, I am putting 1 into the CSR to start the conversion and I do get a 
200(8) indicating that the conversion is complete.  I wonder if this 
means the A/D chip is OK but something else, like the multiplexer chip 
or gain amp is fried.

On 2/6/2022 12:33 PM, Jerry Weiss via cctalk wrote:
> Are you triggering an A/D conversion via the CSR or external signal?  
> Then check the A/D done bit.
>
> See  EK-AXV11-UG-02 Chapter 4.
>
>    Jerry
>
> On 2/6/22 11:20 AM, Douglas Taylor via cctalk wrote:
>> 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
>>