G4 starts up but screen is blank.

Boomer · Apr 2nd, 2008, 03:16 PM

Any ideas what this could be? Just got a panic call from my daughter at university. Her imac G4 screen is blank. She thinks the computer is starting up OK, but the screen is completely blank. It was OK last night when shut down. Now is not a good time for it to be down as exams etc are just around the corner. Please help! Thanks.

chas_m · Apr 2nd, 2008, 06:53 PM

Is there ever a GOOD time for a Mac to go down?

Anyway, first try unplugging the whole thing, wait 20 minutes or so, then plug it all back in. This may resolve the issue.

If not, try starting up the machine and holding down the S key to bring up single-user mode. If you get video, ah good (see below). If you don't, oh dear.

If you get video on single-user mode, just type "exit" or "reboot" to get the machine to start up. We've now determined that there's no video hardware failure, which is a Good Thing. From here you should probably try starting up from the original system DVD and run Repair Disc and Repair Permissions. Disc Warrior, if she has it, would be another very good idea.

If you didn't get video on single-user mode, the assumption has to be that there's a serious hardware problem. Before freaking out, you can do the following:

1. Connect the nonfunctional iMac to another Mac computer via a Firewire cord. Start up the iMac and hold down the T key to get it to boot in Firewire mode (you might get video on this, you might not). The hard drive of the iMac will then show up on the connected Mac, and you can copy her user folder (or the really important stuff therein) onto another drive so as to have a backup.

2. Once that's done, take it to a local authorised service centre.

eMacMan · Apr 2nd, 2008, 09:59 PM

You did not mention which variety of G4. If an iBook or mini try zapping the PRAM.
"Command option p r" at boot keep that key combination held down until you hear the start-up chimes 4 or 5 times. This is one of the few instances where zapping the PRAM may accomplish something.

If it is an iMac, eMac, tower or Power Book replace the PRAM battery before trying more drastic measures.

Boomer · Apr 2nd, 2008, 11:03 PM

Thanks for the replies guys. Sorry, it is a G4 imac (lampshade). From what she tells me, all sounds are normal on startup. She thinks it is waiting (if we could see the screen) for her password input. That tells me the computer is actually starting up but the video is kaput. What that might be I think, is a job for an apple technician. We are looking to buy a used G5 right now to help her get through this year. If we can fix hers, she will get it back and we get a newer imac for the house as this one is a old G3 600 machine. Again, thanks for the replies

monokitty · Apr 3rd, 2008, 10:55 AM

If the iMac G4 has suffered from hardware malfunction, it is not worth repairing in the majority of cases, especially when the hardware failure is connected to its video (logic board, inverter, display). The used G5 you're looking at will do a much job in any case.

Malco · Apr 3rd, 2008, 04:42 PM

Apple - Support - Discussions - kimacfp: iMac G4 monitor is blank. ...

This guy was able to boot via the option key start-up.
Yet another iMac G4 flat panel boot-to-black - macosx.com