hi, I have now the same problem, but I'v got a Compact qtof. However the digitizer board in my case is correctly fixed. Did you finaly solved your problem ensuring tight fixing in its slot??
Digitizer is in the PC right? So before switch on PC, I push the digitizer card firmlyy into the slot. So helpful. You also monitor the temperature of the digitizer card in the sevice mode. It is so hot and cause the large noises. Now I use a small fan to blow and decrease the card temp. Card is quite expensive.