>>2934027
Welp, I connected the board to a power source and what do you know - nothing happened. The display did not come on and the MD mechanism didn't do anything when I pressed the eject button. The connector that is supposed to be supplying power to the inverter seems dead as well. It showed 2.8V and falling at first, so I disconnected the power source, shorted the pins of the connector, connected the power source again and it now shows 0.22V. I guess there was some leftover charge in one of the capacitors.
Not entirely sure if it's broken or it just doesn't do anything until you connect it to a master unit via bus cable.
Also I've noticed a residue on the board and some cold joints on the big inductor coils (circled in my pic). Does that look like water damage, or flux residue from a prior repair?