Hello Prusa,
Before sending this card for repair, I would like to ask you a couple of questions and make some troubleshooting to determine if the cards is effectively not working properly.
Was the card working properly before, and just started failing now? If so, do you recall doing anything unusual, in particular to those channels that are not working?
Every line of a PXI-6508 comes with a 100KOhm connected to it, so you might want to try replacing the resistor in these lines and see if you get data that you desire. (If this is the case, it will save you the time to send the card over for repair and have it return to you.)
Please let me know how everything works out.
Thanks,
LA