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

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Black screen no booting sound

Hi guys, I have iMac 20"/2.4GHZ/2GB/1TB/SD/AP/BT.

Suddenly screen become black. When restarting I can hear HDD and CD but not booting sound. Connected iMac to TV, nothing. Please help to find problem.

Thank you!

Update

Here is little update. I chek power supply, according this table

http://guide-images.ifixit.net/igi/PGEio...

my supply is fine.

Also three LED's are solid green.

PLEASE HELP!

Answered! View the answer I have this problem too

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You literally have the exact same problem as I'm having with my 24-inch iMac! I'm taking it to the Apple Store today to have them diagnose it. I'm fairly certain that it could be the power supply. I doubt it's the logic board because nothing's ever happened to it. . . . Power supplies are known to suddenly die. Logic boards-- not so sure about that.

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I just got back from the Apple Store. They said it could be anything shorting out the power. Like a bad disc drive, the hard drive, anything that could be pulling too much power. It could also be the power supply or the logic board. These things are pretty obvious, but I'm going to go ahead and order a new power supply for my 24-inch iMac and see if it fixes the problem. I've isolated every other part and that's doing nothing. :|

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Let me know if power supply will resolve this issue. Where do you buy parts for your Mac? Thanks.

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Hmmm... Hearing about the LEDs means that your iMac should be working properly. Have you tried resetting the PRAM?

http://support.apple.com/kb/ht1379

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Tommy, I did PRAM reset- no results :(

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Chosen Solution

Here. iFixit and eBay are the places to get them, but hardly anyone on eBay sells parts for these iMacs so I bought the power supply for my 24-inch iMac here. It's a very good price, too. I thought for sure it would be super expensive from iFixit. :)

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Tommy, did you have replaced power supply? Is this was an issue?

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Not yet, Roman. :) The new power supply comes in the mail tomorrow. It should do the trick!

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Just so you know, Roman, I installed the new power supply and it didn't help. After examining the logic board, I've discovered an exploded part on the board. It MAY have had something to do with the previous owner plugging in something dangerous to the USB ports or something. It's pretty bad. :/

Anyway. It's the logic board. Nothing else. :(

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WOW, logic board at least $400 !!! Keep as posted. I think I have same issue. :(

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Most Helpful Answer

Which three LEDs?

LED #3

Indicates that the computer and the video card are communicating. This LED will be ON • when the computer is communicating properly with the video card. If LEDs 1 and 2 are ON and you heard the startup sound, but LED 3 is OFF, then the video card might be installed incorrectly or need replacement.

LED #4

Indicates that the computer and the LCD display panel are communicating. This LED will be • ON when the computer is turned on and video signal is being generated. If the LED is ON and there is no image on the LCD display panel, the LCD display panel or inverter might be installed incorrectly or need replacement.

Hook it up to an external display and let us know your results.

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OK, when iMac is in standby mode-first LED is ON. When iMac starts, first, second and third LED's are ON. Fourth LED is OFF and no startup chime. Connected to TV, nothing on TV.

Hope some one can help me. Thank you guys for your time.

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So, I connect iMac to TV, no signal. Here is little video: http://www.youtube.com/watch?v=3JjjVLWyk...

Thanks.

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Roman will be eternally grateful.
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