Model A1225 / Mid 2007 and Early 2008 / 2.4, 2.8, or 3.06 GHz Core 2 Duo processor

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iMac won't start. Bad power supply?

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

Answered! View the answer I have this problem too

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I set up a genius bar appointment this morning to see if Apple could confirm the power supply. :/ I hope they do!

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Deck the Halls
With tools and Fix Kits

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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.

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Number one LED is on most of the time when the power supply is gone. But not #2. Just replace the power supply.

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good to see you back..hope you're feeling better? x

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Thanks Polly. I actually shaved my face for the first time in 10 days. I hope I'm back at least a little bit. Getting Radiation sucks but a least I glow in the dark for Halloween.

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Oh no! Mayer, you got radiation!? From what? I hope you're doing okay!

P.S. I bought a new power supply from iFixit. It will be here tomorrow. It's looking hopeful that that'll fix it! Just keeping my fingers crossed!

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I got Radioiodine I-131 from the Nuclear Medicine department at my local hospital. It is meant to kill my thyroid which is overactive and causing heart arrhythmias. Have to get that right before they crack my chest open.

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mayer, you hang in there and let them get you fixed up. Take it easy and take care of yourself, and remember you got some friends on here pulling for you.

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This is the expert answer, and sounds similar to your problem. iMac "Core 2 Duo" 2.4 24-Inch (Al) completely dead. Help! good luck

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I already read through that post, and it helped me suspect the power supply greatly. His issue is somewhat different though. His iMac had no power at all. I appreciate the reply!

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I never said I was an expert! lol..more that this has the light "codes", our lovely resident guru on Mac's is a little otherwise occupied at present. I think the guys that answer on here probably fix more machines that the average "genius"...hopefully one of the guys will see your question and help you out. Replace or repair your PSU and see what happens?

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Yeah. I myself am generally more experienced than the Geniuses at Apple, but much more so in the way of Apple laptops. I know rather little about the desktops. :) I bought a power supply this morning from iFixit. After isolating just about every part, I think it's a safe bet. I'll let you know how it goes. :) I'm just praying it's not the logic board!

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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. :)

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Photo's, let's see what you mean! Never say never.. Have a g5 ongoing and iBook. Waiting tools and good karma.

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Bad news everyone! After extensive studying of this board, it's pretty clear that this must have been damaged by a lightning surge. Something went straight into the Ethernet board, blew up an enormous protection capacitor and must have messed with other parts on the board. It seems pretty unlikely that this can be repaired. I'm keeping hopeful though!

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replace the cap, shouldn't it have stopped any further power surge? you never know...might be a $0.75 fix!

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Haha. Thanks for your reply, but I already did replace the cap. No dice. The trick with it, too, is it seems like the original owners for whatever reason tampered with the inductors that are parts of the USB and the Firewire ports. I'm thinking that their crude work has something to do with the board not working, too. You see, the USB ports will power a mouse (the laser lights up), but they won't power a keyboard. There's something wrong with them too. I'll let you know what ends up happening here. One thing's for sure, I'm not giving up yet!

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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????

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Howdy! The power supply should have these voltages:

All unlabeled pins have 0V.

Block Image

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

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TommyJames337 will be eternally grateful.
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