Reseat the RAM, unplug disconnect all external devices, floppy drives, SCSI, etc., except keyboard and mouse, disconnect internal SCSI hard drive cable from logic board, check Lithium CMOS battery (purple and green) for correct voltage, zap the P-RAM (Parameter RAM), if there is a ROM SIMM, then reseat that. If all else fails, remove RAM, disconnect internal SCSI cable, remove Lithium battery and turn on. Power on for 5 seconds then turn off. Reconnect everything and see if it turns on and boots. If not, I would suspect a bad capacitor problem or a bad filter on the logic board.

Let us know what you do.

73s 8)