How do I test the power supply?
i have an unresponsive intel imac and i was wondering if there is a way to "jump start " the power supply so that i can see if it is functioning with my meter and maybe a pinout . also are there any good sources for apple component level repairs like board repair ? the only thing i have found so far is the g5 imac info about cap replacement
-thanks in advance
you will need to connect the green wire to a black ground wire via a high ohm resistor, this is the case with most power supply's but basicly you need to connect the "Standby Lead" to a "Ground" lead with a high enough resistance to make it think it is on, you could also do this with the computer powered on.
Just to throw a much less technical option out there...
Have you checked the diagnostic LEDs on the logic board? Upon removing the access door and front bezel and peeling up the black EMI shield, there are three small LEDs above and to the right of the RAM slot.
The first indicates that the machine is receiving power at all.
The second (when pushing the power button) indicates whether or not the logic board is receiving power from the power supply.
The third indicates whether or not the display is communicating with the logic board.
Does the second LED light when the iMac is plugged in and the power button is pushed?
As always - great care to be taken on any mains powered device, if you work on the mains voltage part.
I suggest at first to check the power supply (without connecting it to the mains) for obvious faults like open circuits, fuses, burnt trough resistors, shorted rectifiers.
then, I would check if there are any output voltages once the PS is connected to the mains - just checking generally the low voltage output area.
All this is non specific (I have no first hand knowledge of the PS in question) but has worked for me on anything from TV's to terminals to computers etc.