Model A1224 / Mid 2007 and Early 2008 / 2, 2.4, or 2.66 GHz Core 2 Duo processor

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Will not Turn On; Diagnostic LED 1 appears but no others.

Hello, I have the aforementioned iMac EMC 2133 A1224 2007 20" model.

I received this, broken, from my boss. He doesn't have the time to fix it so he gave it to me.

I was under the impression it was a bad power supply but the fact that diagnostic LED 1 is lit green makes me weary to spend money on a new one.

When I press the power button, nothing happens. I resat the connection and that has not made a difference. I have also tried an assortment of different RAM sticks that I had laying around to rule that out.

Any ideas?

Thank, Tony

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A bad power supply will give a green #1 lit unless it completely burned out. That rarely happens. Do you get anything else when you press the power button?

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Nothing at all changes when the power button is pressed. I disassembled and reassembled the computer to check for visible signs of damage and found nothing. This at least restores my confidence in swapping out the power supply and hoping for the best.


If you have big hands, like I do, attach the cable that plugs into the backside of the power board before completely screwing it down. My tech has no problem with this but I do.


I just replaced the power supply with a known good one and I still get the green light but nothing happens when I press the power button.


Why do you think the power supply is a known good one?


I received it from a friend who has the same exact iMac but his display is broken. His iMac powers up besides the display with this one, mine won't react to the power button. I may bite the bullet and purchase a bare logic board minus the processor and GPU and just transplant everything over.


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Tony will be eternally grateful.
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