Overhaul/repair of a Celestron CGEM mount after a power surge

Problem:
A Celelstron CGEM mount exhibits unusual behavior during use, such as motor misfiring, spontaneous shutdown, etc.
These mounts are normally known and appreciated for their high reliability and robustness.

After connecting the mount to a laboratory power supply, extreme voltage spikes appeared, leading to the unusual behavior.
(See video, left voltage indicator).

To inspect the interior of the mount, loosen the four screws on the plate housing the control instruments.

After opening the mount, which houses the two motors and the circuit board, a chemical/slightly burning smell was immediately noticeable.
This and other indicators (e.g., BOTH motors were not running correctly, the controller exhibited delayed responses) suggest a likely incorrect or faulty power supply, which must have led to a current overload and caused this behavior.

Solution:
Celestron offers a so-called Motor Assembly Set, which includes one or both motors and the circuit board.
This allows you to replace the defective motors and the circuit board.
After installing the two motors, you need to carefully adjust the gears to match each other.
To do this, loosen the two medium-sized set screws on the opposite side of the mount opening.

These provide a clear view of the two gears, which must mesh precisely. The gap is controlled using the two fastening screws per motor.

CAUTION: Make sure you tighten the screws on the motors. If you want to be on the safe side, use Loctite to secure the screws.

A test with the connected hand controller will show whether you were successful or whether the gap is still too large or too close.

After everything was replaced, the lab power supply showed normal voltage values.

The final functional test revealed no abnormalities so far.

If that's too complicated for you, feel free to contact us for exchange and testing (for a small fee) and/or updates. ;-)