Dave, It is an interesting question. On those PS-2 5V boards that I have seen bad with a short. Draw high current at power up, one of the filtering capacitors is almost always blown/split. Whether that was the cause or the reaction is unknown. There also is a pair of diodes that rectify AC to DC for the board that usually can be found shorted too.
I have one board that is shorted but the diodes seem good, so I am not sure what the fault was/is.
Can't easily work on these boards unless it is an audio amp issue, light FET or light/smoke Line driver.
Wish it was that simple.
As Barry says, once your board does fail, one alternative is to upgrade to the PS-2 3V with 5V connectors.
No PS-3 kits yet, and that will be a much more involved upgrade as all the lights need to be changed to LEDs at this point. G