DEC AXV11-C analog board

[Douglas Taylor]

I just took another look at the AXV11 board.  The A/D module has a 
diagram glued on top which shows the block functions of the device.  If 
you look close the pin numbers are listed where signals are brought out 
to the 36pin connector that plugs the module into the host board.
I may be able to inject a signal on one of the inputs and see how far it 
gets.  I think I can trace it through the multiplexer, the programmable 
gain amp and to the sample and hold and see what the A/D chip input is.

Doug

On 2/6/2022 12:26 PM, Nigel Johnson Ham via cctalk wrote:
> Now that I have thought a bit more, I think it was the DT2762
>
>
>
> The board was made by Data Translation.  There is an identical board 
> sold by them, in the DT2x6x series but I can'r remember the exact number.
>
> Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU
> Amateur Radio, the origin of the open-source concept!
> Skype:  TILBURY2591nw.johnson at ieee.org
>
>
>
> On 2022-02-06 12:20, 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
>>