Compumotor S Series Drive - Help Required

Hi does anyone have any experiance of trouble shooting compumotor S
series drives?

My motor function error light won't extinguish. According to the
manual this happens if there is a poor motor connection or short in
the motor.

Ive checked the motor, connections etc and recon it to be the drive
but as Compumotor want £150 to even look at it and the price of a
new drive modern drive is less than this Im tempted to try and find
out whats wrong and if nothing comes from it Ill chuck it and buy a
modern replacement.

Any help welcome Id particularly like to find out how the error is
sensed and what I can meaure to test the function of various parts
of the drive.

Thanks
Fred