View Full Version : G3 iMac Wont Start

11th May 2008, 01:38 PM
Dad's new/8 year old G3 iMac will not start. It makes the gong sound then you can hear the static sound of the screen and the spinning cd but the screen stays black.
I have tried re-setting the pram, I hold the command, option, r and p keys for 60 secs and only the first gong sounds.
I have tried the c key for the install disc, as well as option and also the t key , all to no avail.

Any clues, help would be muchly appreciated.

11th May 2008, 02:24 PM
Possibly a dead battery?

11th May 2008, 02:28 PM
Possibly an issue with the screen....maybe everything is working but the screen is 'busted';)

11th May 2008, 03:31 PM
Try plugging in an external screen to see if you have an internal screen issue.

11th May 2008, 05:00 PM
Also reset the PMU.

Resetting PowerBook and iBook Power Management Unit (PMU) (http://docs.info.apple.com/article.html?artnum=14449)

11th May 2008, 06:23 PM
Try taking the cover off and replacing it. Or tipping it upside down a couple of times. Or plugging it into a different powerpoint. All of these methods have worked for me in the past. I have had similar problems with a couple of G3s now - If you do a search you'll come across my cries for help and all the great, helpful replies the gurus gave me.

Good luck,

11th May 2008, 07:21 PM
unplug and leave it off for a while and then try again. Also try starting it upside down. Thats what work for me.

11th May 2008, 07:30 PM
unplug and leave it off for a while and then try again. Also try starting it upside down. Thats what work for me.

Care to make a video of you putting your iMac G3 upside down while turning it on?


kim jong il
11th May 2008, 08:15 PM
Did you install OS X on it without checking that the firmware was up to date first; via FireWire maybe? The black screen while indicative of flyback transformer failure (it drives the CRT) doesn't mean that is the case although I suspect it is. When OS X was first released it was found to cause the dreaded black screen issue on the iMacs. Apple responded by releasing a firmware update that prevented the flyback transformer being overdriven and if updated straight away could restore functionallity before permanent damage occurred. Early versions of OS X included a firmware checker that prevented installation on G3 iMacs with the older firmware. While I assume this is still the case I don't actually know. Certainly I have inherited a similar G3 where the owner had installed Tiger via "Target Disk" mode which worked for a while but killed the flyback transformer. These iMacs will work just fine with an external monitor.

Plug an external monitor into the VGA port at the back of your iMac and (assuming it displays properly which it almost certainly will) check the firmware revision installed which will be found in "About this Mac"/More Info. Click on "Hardware" and the "Boot ROM Version" is the firmware revision. In your case it should be 4.1.9f1. If this is not the case, which I suspect it is, then you may have the issue I have just described.

19th May 2008, 01:44 PM
Well, well, well, I left the iMac off with the power lead out for the last week, my happy surprise when I plug it in, turn it on and starts up perfectly.