I have a 2003 iMac G4 1,25Ghz 17". It runs fine and I have not had any problems except this annoying issue - it takes several attempts to get it to start-up. For example, first thing in the morning, I press the power button and it locks at the white screen with the grey apple logo with faint grey or white vertical lines. I repeat restarting the iMac with the power button and it happens three or so times and usually boots up fine to the Desktop on the third or fourth attempt. After that it runs fine. I have changed the internal HDD as it was failing with a new unit, upgraded the RAM, changed the PRAM Battery, zapped the PRAM and PMU, repaired disk permissions and even tried a clean install of the OS. In addition, I had a look at the logic board and all the capacitors looked fine and all connectors were in. It has lead me to think it may be the PSU that is on its way out? System diagnosis is fine, RAM is OK and there are no common symptoms of bad capacitors on the logic board like freezing, crashing and graphic artifacts on screen. The previous owner said he never had any problems but admitted the iMac was rarely turned off - it would go to sleep when it was not being used. I would be most grateful if anyone could throw some light on this or share similar experiences before I start spending money on replacement parts in the hope it may fix the issue. Thanks in advance. Iain

Have you tried booting from your Apple Hardware Test disc and running a full test? At this point in time, I would recommend backing up all your critical data if you haven't already.

Hi and thanks for your reply. I don't have the Install Disk 1 which the correct AHT is on - just bought the computer a few weeks ago and it only came with the five Software Restore disks. On the Apple Support page there is no AHT to download for my particular iMac (USB2 version), only the others. All data is backed up via Time Machine, no worries :) Lately, I have been keeping the iMac on all the time (it sleeps when I do) and have had no problems at all. Think it might be a dodgy capacitor in the PSU? It resembles a poor starting motor or fouled spark plugs in an automobile. Once it starts, it is fine. (Scratching head) There are no funny sounds or burnt smells from the PSU. Cheers. Iain

sounds like a video card problem to me... the faint lines on the monitor kinda give that one away.. I'd look in that direction...