No chime, black screen, white light steady
If iMac is off, but power is plugged in, number 1 diagnostic LED is on.
If iMac is on, no chime, fans go max, black screen, white light stays steady and number 1 and 2 diagnostic LEDs are on.
If LCD unplugged and external monitor plugged in, can't turn off, it turns right back on, once external unplugged, it turns off.
Also tried with detaching everything (add on cards, hard drive, etc.), no results.
Maybe the power supply? Hope its not the logic board....
Is this a good question?