Level 1 (51 points)

Late 2009 iMac starts with black screen and slow boot

I think my late 2009 iMac has come to the end of its life but I'd appreciate any advice which might prolong it.

More often than not, my iMac starts with a completely black, blank screen. When this happens, I know the mac is definitely working, as I can hear email notifications etc come in. I've tried connecting an extra screen. This comes on when the iMac screen comes on but doesn't come on when the iMac starts with a black screen. This is no help.

On the last occasion when it started properly, I decided to simply leave it on. However, after three days I found the fans going like crazy, although the mac wasn't hot, so I thought I'd better turn it off.

It hasn't started properly for three days but it has just come on, after trying half a dozen times today. When it does start properly, it takes much longer to complete the start up process than it used to, Although the screen illuminates within a second or two of pressing the power button and hearing the chimes.

I cant complain as I've had fifteen years from it, almost problem free but if there's any way I can get a few more years I'd be thankful.

Any advice would be gratefully appreciated.

N.b. I'm in the UK.

Posted on Nov 9, 2026 9:42 AM

8 replies

den.thed

Level 10 (99,154 points)

Nov 9, 2026 10:31 AM in response to Rob Bartholomew

An intermittent failure to light the display can be caused by several different issues.

1) a failing display

2) a burnt backlight cable

3) a failing backlight inverter board

If you have or can borrow an old external monitor that has DVI or VGA inputs.

You can connect it to that iMac using a Mini DisplayPort to DVI or VGA adapter for testing.

It's not worth it, to buy an external display or adapter just for the purpose of keeping or testing that iMac.

If you are going to any spend money, it's better to spend it on a new or newer Mac and recycle the 2009 iMac.

MrHoffman

Level 10 (169,253 points)

Nov 9, 2026 11:58 AM in response to Rob Bartholomew

Rob Bartholomew wrote:

Thanks for your reply den.thed.

I borrowed a display from a friend and connected it via my iMac’s MiniDisplayPort to the HDMI socket on the external display. The external display worked when my iMac started properly but not at all when my iMac didn’t start properly.

Does that make it easier to identify the problem?

R

It does make it easier to get a backup, and to start the process of replacing this iMac.

Getting that backup is your bestest and first priority too, even if you (later) decide to try running Diagnostics or such.

I wouldn’t assume Diagnostics will isolate the error. Some errors do get missed, and particularly transient errors.

You may not get another chance to get the data, depending on the failure already in progress here. Backup, first.

den.thed

Level 10 (99,154 points)

Nov 9, 2026 12:26 PM in response to Rob Bartholomew

Rob Bartholomew wrote:

Thanks for your reply den.thed.

I borrowed a display from a friend and connected it via my iMac’s MiniDisplayPort to the HDMI socket on the external display. The external display worked when my iMac started properly but not at all when my iMac didn’t start properly.

Does that make it easier to identify the problem?

R

You're welcome.

That sounds like the old iMac also has a failing internal drive.

One way to work around that, is to format and install OS X on an external USB drive, then startup and run from it.

see > https://support.apple.com/en-us/111336

Sadly that old iMac can only use a slow USB-A external drive connection and that will be somewhat slower than running from a good internal drive.

Rob Bartholomew Author

Level 1 (51 points)

Nov 9, 2026 11:27 AM in response to den.thed

Thanks for your reply den.thed.

I borrowed a display from a friend and connected it via my iMac’s MiniDisplayPort to the HDMI socket on the external display. The external display worked when my iMac started properly but not at all when my iMac didn’t start properly.

Does that make it easier to identify the problem?

Rob Bartholomew Author

Level 1 (51 points)

Nov 9, 2026 12:05 PM in response to claus237

Hi claus237

Yes, everything is backed up on Time Machine. The most important stuff is also on iCloud.

I've never been to Denmark but my partner has visited when in her previous marriage. She says Denmark is the most wonderful country and the people are very friendly. I'm determined to visit with her in the not too distant future.

As for Greenland - what a crazy idea? Stay strong, he's on the way out.

Good Health

Rob

claus237

Level 2 (256 points)

Nov 9, 2026 11:55 AM in response to Rob Bartholomew

You probably, have a Time Machine Backup, in case your, old iMac crashes completely?

N.b. i`m in the DK................"The country, that refuses, to sell Greenland"

Rob Bartholomew Author

Level 1 (51 points)

Nov 9, 2026 12:35 PM in response to MrHoffman

Thanks Mr Hoffman,

I have now done that. All files and folders are safe. It still a real pain!!!

Thanks for your advice

Regards

Rob

claus237

Level 2 (256 points)

Nov 9, 2026 12:54 PM in response to Rob Bartholomew

Thanks, for your feedback from the U.K.

I completely agree with you!

Have a nice day.

Originally posted at discussions.apple.com/thread/256391476