There is usually a cap in the startup circuit that can cause that. It will be on the hot side. Sometimes you got a resistor to the raw B+ which hits a source from a tertiary winding that powers the drive circuitry. Caps on the secondary side don't generally cause that, and even if they get slightly weak there are more caps on the mobo to take up the slack. If they get really bad and the ones on the board are not enough you might get erratic operation and maybe even data corruption. Even when it is not that bad those caps being bad can cause it to be more susceptible to momentary power glitches one of which just destroyed the OS in one of my boxes. I'm going to reload it one of these days but haven't gotten around to it. Lazy, and when I get unlazy I got work to do. In that one if the caps were in better shape they would have held a charge long enough, there were three outs of duration in milliseconds. It shouldn't have affected anything.