Imac won't start

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whybrick Author

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Imac won't start

Hello?

My iMac won't start.

I hear Optical Drive spinning for few seconds but no screen and no hard drive noise and absolutely no response at all.

I opened up the iMac and i found these.

when Power is ON, LED 1,2 and 3 are ON but 4 is OFF.

they say there might be a problem with graphic card but i also foung this

this is Power Supply Unit, Liteon Pa-3241-02A

Lower-right corner as you see on this photo above, there is a thing burned.

I don't know if this burned thing is preventing the iMac from starting up.

Or i should replace graphic card as LED diagnose advises.

Please advise

thanks

imac, Mac Mini, Cube, TiBook, Color Classic, Newton, iPhone, iPod Nano & Mini,, Mac OS X (10.4.10), iMac Cherry, Aibo

Posted on Sep 17, 2012 10:53 AM

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Answer 1

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BDAqua

Level 10

238,871 points

Sep 17, 2012 1:05 PM in response to whybrick

Fantastic work, I believe you've found the culprit. 🙂

Of course that doesn't mean it didn't affect the Graphic card though.

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Answer 2

whybrick Author

Level 1

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Sep 18, 2012 1:12 PM in response to BDAqua

Thanks BDAqua,

Here is what i concern as well.

First Light is always ON after i Plugged power cord to the back of my iMac 24. After I turned it on, all three lights except the last one were ON and OD started spinning, I believe because it made noise. But after a minute or so, OD stopped and all of sudden, no activity at all.

Hard drive never even start spinning, no chime, no warning, no screen activity whatsoever. but all three LED light remains ON all time unless I turned it off.

PSU indicates physically damaged. I checked output voltage with my tester. some of them gives me some voltages but some not. but I don't know what that means i just picked and poked with test needles.

I don't know if it is worth trying to replace PSU with spending little more than $100 even though disgnose LED Light indicates power has no problem to feed system.

thanks

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Answer 3

BDAqua

Level 10

238,871 points

Sep 18, 2012 1:20 PM in response to whybrick

Yeah, tough decision, I'd like something better than my 24" iMac/2007, but the newer ones, besides being Wide Short Screens, seem to have too many problems, & only run iOS10.7 or iOS10.8 😉

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Answer 4

whybrick Author

Level 1

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Oct 11, 2012 8:10 AM in response to BDAqua

BDAqua,

Finally the PSU has been replaced, $110 including shipping from MacPalace.

Now i see 4th LED light on and hard drive starts spinning.

somewhow, HDD has been damaged and required to be formatted.

successfully Snow Lwopard has been installed and iMac is working perfectlyso far

So all of the problem began from that burned piece on PSU??

thanks

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