iMac 2009 27’ all in one computer

[Deb741]

I’m having problems with my computer .. The computer turns on and about 10 minutes shuts off and goes to black screen.. It does this continuously with the black screen. Please Help!!

 

[Sheepish-Lord]

If the computer shuts off on its own you either have a power cable issue or an internal hardware issue which you won’t be able to fix yourself.

Might be time to retire the 13yr old machine.

 

[The_Croupier]

I’m having problems with my computer .. The computer turns on and about 10 minutes shuts off and goes to black screen.. It does this continuously with the black screen. Please Help!!

Does it shut off or just black screen?
Put your ear near the vent on the top of the imac when the screen goes black, if you hear the fans spinning the Mac has not shut down which to me would probably indicate a failing backlight power board.

 

[Fishrrman]

At 13 years old, may not be worth fixing any more.
Might be time to start looking for a replacement -- even a refurbished or used Mac.

 

[Bodhitree]

The thing is, Apple doesn’t make the parts needed to repair such a relatively old machine anymore. So if there is some issue with the power supply or with the main board from heat, the only option might be to get a similar machine off ebay and cannibalise it for parts. That is not a small undertaking, requiring considerable technical know-how.

It might still be something simple like dust buildup or bad thermal paste. If you take it to a Mac shop they would know how to give it a simple clean. But if that doesn’t do it it looks like some kind of hardware fault.

 

[BeatCrazy]

I’m having problems with my computer .. The computer turns on and about 10 minutes shuts off and goes to black screen.. It does this continuously with the black screen. Please Help!!

Possibly a bad/failing power supply.

As others mention, it's probably not worth fixing since I imagine you're not eager to source down parts, learn how to take apart an iMac, etc. And a repair shop would likely charge you $300+

However, please don't toss it out in the garbage. There are lots of MacRumors members that could fix it themselves and/or salvage perfectly-good parts.

Consider offering it up for free/cheap to a forum member that is local to you?

 

[rpmurray]

I’m having problems with my computer .. The computer turns on and about 10 minutes shuts off and goes to black screen.. It does this continuously with the black screen. Please Help!!

Do you get to the desktop before it shuts off or does it remain in the booting phase and then shut off before you can log in? Do you see a progress bar while booting? Hear the startup chime? What version of the OS are you running on this?

Is it booting from an HD or an SSD? Internal or External?