We are having intermittent problems with our QT20, alarm 15 system malfunction. Today it popped alarm 15 during a run and during a few power shutdowns and restarts it kept coming back.

Alarm 15, drive 1 =A6, drive 2 =f6/e7, drive 3=e6.

Can anyone point me in the right direction? My searching has not lead me very far... Much appreciated