Error 14 Prosetter 74

my Heidelberg Prosetter 74 displays ERROR 14:

This is the User information:
An error occurred in the mirror motor unit...
THE RECORDER HARDWARE IS DEFECTIVE

This is the Technical Information:
TRHE TIME MONITOR REPORTS TIMEOUT DURING THE SPIN-UP PHASE OF THE MIRROR MOTOR....
CHECK THE MIRROR MOTOR UNIT.

---- The mirror motor apears be fine. Could be because there is a bad cable or any defective sensor or something that is more encouraging than having to buy the mirror?

I appreciate any help.