Thanks for posting an update on your problem. If the gearing/mechanism was jammed somehow, probably the DC electric motor windings were drawing high current through the control relay contacts when you operated the up/down switch. I would think there should be a protective fuse or breaker in the motor drive circuit (and a thermal overload inside the motor) that should have tripped open. Of course that increases the "build" cost and may have effectively “reduced” a need to repair......cost to owner.
__________________
|