iMac Starts Up And Then Shuts Down ...

Question

Lindsay Ash Author

Level 1

5 points

iMac Starts Up And Then Shuts Down ...

Hi ...

I'm hoping that someone out there can help me ...

I purchased an Apple 24" iMac about 3 years ago ...

It was pretty much working perfectly until 2 days ago ...

The last time it was fully operational I'd just switched the computer on for the day - opened iTunes - and was using the FINDER to find approx 600 MP3s to add to iTunes ...

Whilst the FINDER was searching for the MP3s the iMac froze ...

So I decided to RESTART the computer by holding the POWER BUTTON to shut the computer down ...

I gave the computer around 10 secs to shut down ...

Then when I pressed the POWER BUTTON to START the iMac again it reached the grey screen with the Apple logo and the rotating dial ...

The computer then started emitting an audible clicking sound as if it was searching for / organising data ...

The sound eventually stopped but the iMac froze on the grey screen ...

So again I decided to RESTART the computer by holding the POWER BUTTON to shut the computer down ...

I gave the computer around 10 secs to shut down ...

Then when I pressed the POWER BUTTON to START the iMac again it reached the grey screen with the Apple logo and the rotating dial ...

And froze again ...

I followed the instructions contained within the EVERYTHING MAC booklet ...

I tried holding the OPTION key whilst starting up ...

I tried holding down the COMMAND OPTION P and R keys to reset the PARAMETER RAM ...

I also tried holding down the D key whilst starting up to test the Apple Hardware ...

My iMac passed the Apple Hardware Test ...

However every time I now try to start the iMac it reaches the grey screen (Apple logo / rotating dial) and then shuts down after approx 1 minute ...

Is this simply a boot problem ? ...

What alternatives do I have to boot up / correct the problem ? ...

I'd be ever so grateful if someone out there could help walk me through alternative actions to take ...

Kind regards ...

Posted on Dec 22, 2011 5:22 AM

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Answer 1

a brody

Level 10

82,941 points

Dec 22, 2011 7:45 AM in response to Lindsay Ash

Try to replace the PRAM battery.

Try replacing the RAM with to spec lifetime warranty RAM*:

http://www.macmaps.com/badram.html

If neither stops this from happening, bring it in for service. Your power manager may need fixing.

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Answer 2

Dec 22, 2011 8:05 AM in response to Lindsay Ash

I really dont suspect your ram to be defective. You zapped the pram and nothing else do so.. By the way there is no special battery for the pram. The logic board itself have a battery and the power for the pram is provided by capacitors. But i would be very surprised that this could be the problem. In 13 years i never saw a computer not starting because of the battery.

Hard drive problem: Try to start-up from your installation disk to see if the computer is booting. You will then know if this is something caused or not by your hard drive. If the booting is successfull that way, try re-instal your OS. If that don't work, = hard drive change.

Logic Board or SMC problem: Resetting the SMC could help here. Here's the procedures:

http://support.apple.com/kb/ht3964

If that fail and the step before (hard drive) too, i really suspect the logic board.

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Answer 3

a brody

Level 10

82,941 points

Dec 22, 2011 8:41 AM in response to Alain Boisclair

Alain,

Except for iBooks, I'm aware of no other Mac that uses capacitors for PRAM. If you can find documentation to the contrary, please link to it.

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Answer 4

Dec 22, 2011 11:33 AM in response to Lindsay Ash

Hello

Try target disk mode see if your mac shut down from this way , to do that

hold hon at start up "T" on key board just after startup sound until screen show a firewire logo as screen saver

and wait ..

if by chance you have a second mac you can use a fire wire cable to link it , in that way your mac is like an external hard drive , most easy way to recover data from it

Try start in single user mode , use COMANDE - S at start up

Try start in safe mode , use SHIFT key at start up

if in all case you mac shut down after 1 or 2 min of use , certenly mean a mother board and or powersupply problem

be sure to have perform SMC and PRAM reset at least 3 times each

HTH

Pierre

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Answer 5

Dec 23, 2011 1:07 PM in response to a brody

😉 You are right.

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