Black screen on startup for iMac g5 17inch

This iMac is notorious for bad capacitors. It always seems to happen, even if it was well maintained. The reason is heat and capacitor plague. This is a very common failure. This is kind of Apple's fault, but the capacitors weren't. The heat the G5 puts out that helps kill them is.

Even if you can replace the caps, no. This thing will keep doing it time and time again due to the G5 heat output PPC G5 processors are notorious for. The displays also fail in them too and these use Apple specific TDMS panels and you have to use the Apple part. You cannot substitute it at all in this model.

These are not worth fixing. Sell it as-is to some collector who fixes everything Apple and move on. Get a new iMac that isn't a piece of garbage that won't fail the same way. Just don't get the 21.5" 1.4GHz model.

I've had the same problem several times on my G5 iMac with iSight... on start-up it gets a black screen with a loud fan sound and won't do anything else. The problem seems to occur when it doesn't eject a CD before shut-down (power outage, pulled plug, etc.)

Here's the solution that has worked for me. Unplug all devices (USB drive, printer, etc.) except the keyboard... then reboot with the mouse button held down. The CD will eject and you get a clean boot.

Not sure why this occurs, but it seems that the computer gets stuck trying to boot from the CD and this clears the problem.

Hope that helps!

Try starting it in single mode first....option-command-s on startup , and when the scripts stop rolling on the screen, type "reboot".

I have a first version 1.8 20inch imac, which had black screen and wouldn't work an external monitor iether. everything else appeared to work and I could read the hard drive when hooked up to my powerbook in Target mode. Checked the capicitors and nothing obvious blown. Checking closely one of the capicitors near the screen output cable (there are 2 sitting together on the logic board here) had a very slight bulge in it. I changed it and voila! screen back and a happy mac user again!

Cheers Jeff

PS - cost of capicitor £0.40 and just my time and plenty of guidance on ifixit!

I know this is very old, but I was recently given this iMac from a friend and I can see that Capacitors C5008 and C5009 have gone bad and most likely that is what will happen to most of the iMacs that are like this.

same problem. iMac G5 250GB 2GB RAM Tiger. Got stuck on grey screen starting up, fan spinning at top speed. Forced shut down/restart. Starts up, chime and then google notifier sounds there. Time machine backed up. So system running. But I have a black screen now. Tried hooking up external screen, and resetting PRAM. No success. Any ideas? I'll check capacitors if you think this is a possible problem.

Cheers,

Darko

Thanks for your reply.

I popped off the back. all capacitors look fine in my opinion. No sign of bulging or goop. Actually, maybe I have a good batch of capacitors, because the logic board was replaced in 2006 after I had a random shut-off problem.

My status now: After I reset PRAM (control/option/P/R) and SMU (o/n unplugged) the screen came back to life. But the system got stuck during startup. After I forced shutdown/restarted the OS came up and running, but now I have no video. Unfortunately I could not repeat this effect.

Does anyone have an idea what else I could try? I would very much appreciate it.

Cheers, Darko

I am not sure if this is an appropriate forum...but I installed FreeBSD powerpc64 10.1 and things were going pretty well, running XFCE desktop when the screen went black and now I can remote in using ssh but can't see anything on the screen...

I will try an external monitor when I can get a connector in a few days...but I was wondering if there was a software/command solution. I tries resetting the PRAM, all three light come on and resetting the SMU didn't work

Any suggestions would be greatly appreciated

thanks all

ralph