I have been using an ADC11/12 usb very sucessfully for 4 months to log 9 voltage channels. Suddenly all channels are reading 9.999 volts ( even ones not connected) in my vb software and are just asterix's in Picolog. Yesterday unplugging the USB lead seemed to clear the fault, fault reappeared this morning, this time changing PC and usb lead didn't solve problem. Have checked all input voltages and they seem to be normal. Any suggestions would be most gratefully recieved.