If you have an APQS, Innova or A1 machine, this erratic behavior may be caused by your machine's power cord. These machine cords do not regulate power surges very well, which can lead to surges going into the IQ. A standard surge protector may not fix this. We recommend purchasing the ISOBAR power regulator found at this website:
Plug the regulator into the machine power cord only. It does not need to connect to the IQ.