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

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