I've been given a strawberry G3 iMac 400/DV that is nice and clean but won't power up. So far I've replaced PRAM battery and tried pushing the CUDA switch. On one occasion the power-on button flashed for less than a second, but generally nothing fires up. I do hear a pop in the speakers, which suggests there is some power on the board but not enough to boot. Display remains dark.

Any suggestions on a troubleshooting checklist? Could this be a caps issue?

Rick