Cause1: The power unit cable is not properly connected, or almost disconnected.
Action1: Connect the power unit cable securely.
Cause2: The system power supply breaker is OFF.
Action2: Turn ON the system power supply breaker.
Cause3: An alarm is activated.
Action3: Remove the cause of the alarm, and reset the alarm.
Cause4: The stroke TD (TD2 in the standard system) CAL cable is not properly connected, or almost disconnected.
Action4: Connect the CAL cable securely.