Thanks for the reply. Now that the trace is fused, I did ohm out the 24V pin on the P4 CONN to the return (white wire) and it read 160 ohms, which doesn't seem right. I did the same for the 24V pin on the CONN P3 and it was ~24k ohms, which seems more reasonable.
If I have to replace motor, the motor control board, and buy another new machine control board, it looks like this is going to be expensive even if I do this myself. Might be worth it to just get a new machine.