Fuji DSR 83 DC Drive Problems

I have a old Mori Seiki Lathe with a Fuji Dsr 83 drive. The old drive blew up and destroyed a circut board. I've now replaced the complete drive with a working 2nd hand one. But the main spindle motor isn't doing anything. When turning the motor by hand it generates a voltage. When I tell the drive to go it also puts out a voltage which weakens fast but I think that's a built in safety as it can't see feedback from the motor. Is the new drive no good or should I be looking at the motor? The motor was working fine before the drive blew up. Just before the drive blew, as soon as it had power the motor started turning and not even the e stop would stop it.