393 motor circuit board failure

So this week I was trying to fix one of our broken 393 motors. I took it apart and put a current into where the standard motor wires go into the motor’s circuit board but got no response. I then put the same current into where the board powers the motor and the motor spun. What is the purpose of this circuit board and what do you think caused the board to fail?

Any answers to this? We had the same problem at the State Championship this weekend. A 393 motor died without warning. Motor inside is functioning when the case is opened and power applied direct to motor input, but if direct current is applied to the input wires no response. So something in the circuit. We will be opening it up for failure analysis this week, any advice would be helpful. Anyone have a schematic of the motor circuit board?

There’s really nothing on it, just the PTC IIRC. The 269 motor used to have a resistor as well, never really sure why that was needed. Most likely you have a broken wire of bad solder joint.

Here is what we found:

PCB trace delaminated from board.

Trace cracked, so black wire has no connection.

Suspect that that trace was lifted when we got it and vibration through use cracked it.

will post complete failure analysis write up shortly at Rollingrobots.com/blog