I unscrewed all the screws that line the edge of the main control module plus a few screws that helped hold the wire cover in place. I probed the board and discovered that there is a voltage drop from 33 volts DC to about 6 volts DC when the lights go out and the audio gets garbled. The thermistor, on the bottom right-hand side of the board, is being used as a self-resetting fuse for overcurrent protection. It is heating up and dropping the voltage on the board. There must be a short somewhere. I tested all the diodes, capacitors, voltage regulators, and the audio amplifier. I suspect that it is possibly the audio amplifier (TDA2030AL) and/or the transistors (TIP41C and TIP42C) that are attached to it.

I flipped this second image to make it easier to trace the components of the first image.