I unplugged the sound board connector, A6P1, & checked pin 5 of the aux. power supply to ground & got -6.56v. I plugged A6P1 back in & on the aux. power supply, I checked resistor R7 to ground. The banded side read 13.7v & the other -6.57v. Checking the ohms of R7, I got 0.1. Checking in diode mode, VR1 read -421 in one direction & 1 in the other. CR1 read 944 & 412; CR2 921 & 444; CR3 974 & 510; CR4 read 908 & 422. Does this mean R7 is bad? Edit: When I first it on, there's no sound. After playing a few games, it'll start to play the game music non-stop & sometimes make game sounds. I don't know if this means anything.