Disc board fails to spin disc

I've got a gamecube with an interesting problem. I have another cube that is known working and I've done part by part swaps (motherboard, disc motor, hinge switch) to narrow down my issue. Something on my disc drive board is wrong and it will not spin the disc. Changing the motor to my known working cube proves the motor isn't the problem. I even swapped the good motor to see if that will work, which it didn't. I have a cheap multimeter and the caps are taking a charge and discharging as normal. A reflow of the hinge connector has not fixed my issue. I'm at my wits end and about to call it a lost cause.