Hi, i would pull the unit out and remove the bottom panel and check the gears to see if they are broken. Post back to me.
the gears in the bottom of the unit are not stripped or broken. any other ideas
Does it sound like the motor trying to start?
Do you have a volt meter to test voltage at the motor?
If you have a volt/ohm meter, we can check motor windings and switches from behind the control panel.
The motor runs but seems to get jammed up. When that happens the shafts that drive the ram start rotating back and forth until the motor over heats and shuts down.
Remove the chain. run the unit and see if the motor sticks. If it does you will need a new motor, if not i would be looking at the power screw that the ram goes up and down on.
the problem was actually the door switch making intermittent contact causing the motor to stop/start.
Ok. Thank You for letting me know. I will put in a refund request for you.