1.83 GHz Core Duo or 1.83, 2, or 2.16 GHz Core 2 Duo A1208 (EMC 2104/2110/2114/2124)

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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

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== Unresponsive, How? ==

Can you explain specifically what you mean by an "unresponsive intel imac"? If it isn't booting up, there could be some reasons other than the power supply. For example a loosely seated stick of RAN can probably stop the machine from booting. A better description of the symptoms are needed here, and of the steps you have taken to discover the true cause of the unresponsiveness. Thanks. --Bob

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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?

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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.

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I've turned on several different standard PC power supplies with just a wire, no resistor. I'm not sure if this iMac PSU is different or not.

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oh, ive always used a resistor, just to be safe with any power supply but i guess you don't need it, but some power supply's wont turn on without reasonable load.

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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.

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