Chosen Solution
Howdy everyone! Just purchased a 24-inch iMac Intel from eBay, hoping to fix it. I’ve spent probably 2 hours now diagnosing the problem and I think it might be the power supply. Can someone confirm that for me? When I press the power button, the CD drive and hard drive spin. The first LED on the logic board is always on, but none of the others turn on. I get no startup chime, no screen, and no spinning fans (although one jerks a little when the power button is pressed). Isn’t the second LED to show that the logic board has received power through the power supply? Does that tell me that I should buy a new one? Thanks so much! -Tommy
So, to finish this off, I discovered that the iMac must have been damaged in a lightning storm. The logic board is irreparable, and all hope is lost aside from switching it out. Thanks for your help guys. This was certainly a unique problem.
Number one LED is on most of the time when the power supply is gone. But not #2. Just replace the power supply.
This is the expert answer, and sounds similar to your problem. Click here good luck
Okay guys. I got the new power supply. It didn’t help in the slightest. SOOOO, I took a much closer look at areas of the logic board (which I realized I should have done before I purchased the power supply. haha) and I’ve discovered an exploded part under the sound (?) card on the right side of the iMac!!! It looks as though some device in the USB ports could have caused a short to the board or something! CRAZY! Now, I’m not sure what I’m gonna do, but this case is closed for now I suppose. My iMacs troubles definitely have NOTHING to do with the power supply. :/ Oh well. Thanks for all of your help guys! Hopefully I can repair the logic board. That would be nice. :)
hi i have this same problem only firs led hdd spin cd make noise. Could anyone post what voltage i should have on 12 pins fro psu? Please????
Howdy! The power supply should have these voltages: All unlabeled pins have 0V.
These are the voltages I get without having the display attached. I imagine the pin above the 2.6V one probably has some voltage when the LCD is installed, but with the LCD installed, I’m not sure how someone would measure the voltages. It’d be awfully hard to get your voltmeter probes in there. haha
