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JS24
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iMac won't power on. How do I check this model's power supply?

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My iMac won't power on at all and I suspect the power supply is the issue. I've searched everywhere I can think of, but no one has a tutorial on how to check it on this particular model. I was able to disassemble it without any trouble and I removed and inspected the power supply visually, but I'm hoping someone has advice on how to test it with a multimeter. I haven't been able to find any pinout or voltage information for it. Maybe the same unit is used in other models? Any help would be greatly appreciated.

Edited by: Eric Essen ( )

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mayer
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Just to the right of the RAM slots you will see the diagnostic LEDs. Tell us which ones are one. If just the first then you need to replace the power supply.

Here's the power supply: iMac Intel 24" 2.16/2.33 GHz Power Supply

There's no teardown for this model yet but this guide should get you there: Installing iMac Intel 17" Power Supply

Edited by: mayer ( )

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iMac Intel 24" 2.16/2.33 GHz Power Supply

Power Supply for iMac Intel 24" — Currently out of stock.

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Installing iMac Intel 17" Power Supply

good answer +

rj713,

I'm guessing if no LEDs are on, as is the case with mine, then it's *definitely* the power supply?

JS24,

------------ Yes.

mayer,

If you are replacing your power supply and don't already have a set of small torx drivers the http://www.ifixit.com/Tools/54-Piece-Bit... and http://www.ifixit.com/Tools/26-Piece-Bit... have the required torx bits, plus lots of other handy bits, and are a great deal compared to purchasing the individual drivers.

Eric Essen,

It was, in fact, the power supply. I followed a tutorial on this site to get the case opened and replace it. This is the correct power supply: http://www.ifixit.com/Apple-Parts/iMac-I...

JS24,

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Jenny
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If no lights are on can you say its the power supply or can you say its the power supply and/or the logic board? One would think testing the PS would be in good order before assuming its bad.

Edited by: Jenny ( )

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Matt McCaffrey
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Not for nothing, but my 24-inch mid 2007 iMac also went completely defunct in one power cycle. I actually brought it to an Apple Store where they replaced (according to the paperwork) power supply x2, backplane, and main logic board. They ended up returning it to me "no charge" and pulled the hard drive at my request.

I'm following up to ask you if you have had success with your repair. I'm leaning toward replacement but if this problem turned out to be something simple and mechanical like the power switch, it would be totally worth my time to tear it down and repair it.

Thanks, JS. I'm feeling a little stumped, because Apple says they essentially replaced the entire guts of the iMac and it still was stone-cold dead. At some point you gotta ask, how could that be? I'm glad your repair worked out!

Matt McCaffrey,

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s m
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Hi,

If computer is off, but power is plugged in, number 1 diagnostic LED is on.

If computer 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.

Hoping for the power supply...

Any ideas?

Thanks!

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