Hi and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, proposed preliminary try (if comfortably/safely able to do or have done by somebody else) is to temporarily disconnect where the red and black wires of the motor are connected to the motor board:
Very significant additional information.
The earlier post was in response to the first "... test the motor board and the motor...".
Hopefully, an alternate approach / second opinion can be provide to your concern. The question would be re-opened as I would rather opt out.