Chosen Solution
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.
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: [linked product missing or disabled: IF169-000-1] There’s no teardown for this model yet but this guide should get you there: iMac Intel 17" Power Supply Replacement
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.
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.
