Disklavier

After moving my Mark 3 DC6A, I get the following Error message when I  turn 
on the controller:
 
SENSOR LED ON ERROR
 
 
It completes the boot-up process like normal. 
 
Playback through both the CD player and the floppy drive is  OK. 
 
I have not tried recording, yet.
 
Any ideas what the message means and what it affects?
 
Thanks, Group,  Glen