Can someone help me with these motor/drives, I think the drives are dodgy?

You'll see there is a couple of pics of the motor and the writing on it, it's old (I think it's from 1986).
I also put pics of the amplifier, I'm starting to think they are the problem, when I switched a couple around, the motor that was stalling didn't stall anywhere near as much.
I'm hoping to get some second hand drives, but don't know what type to get, I've tried to find info on the motor but have'nt found squat.

Not much information to go on there. They presumably are DC, you would need to calculate/obtain the size and possibly use A-M-C or Copley Controls type of which there should be one to match those motors.
Al.