No power and ticking from PSU

Hi all,

I'm trying to salvage an old IBM 9494-HBO LCD monitor and am posting here because I think the problem is in the monitor's power unit. Anyway, symptoms:
- Plug in, turn on -> no lights, no power, soft ticking noise from back panel
- Disassemble, disconnect power board from logic board -> louder ticking
- Hook up ATX PSU to logic board's GND,+5V,+12V -> ATX PSU clicks on and shuts off, repeats

I'm getting the impression that this type of behaviour is the PSU sensing an short (or something) and shutting down to prevent burning something out. But if this was the case (implying the the problem is on the board or screen and not in the PSU), why would the power board act the same even when it's unloaded?

TIA