10-11-2010, 12:44 AM
What are the specs on the iMac G5? Does it have the iSight Camera? 20" LCD?
Reason I ask is a few with older iMac G5's with corruption on the screen had an issue with the LCD"s Cable where it plugs into the Logic board. There are 2 small screws holding it in the Jack on the board. In the case of the affected users, the contacts on the LCD's plug got dirty over time. Just unplugging the jack and plugging it back in the issue went away.
At first I thought you put in the new Hard Drive and was going to tell you to take it apart and check. The iSight G5 are a pain to take apart though.
If it's not the plug then it's either the LCD or Video Chipset on the main board since you ruled out OSX by reinstalling.
That LCD cable is very close to there the Hard Drive is By the way and the person who installed the hard drive could have bumped it. Like I said there are two very small screws holding the plug from the cable to the jack on the Logic Board.
Just a note, 10.5.8 Leopard is the newest OS a Power PC G5 will take. Snow Leopard is Intel Only. Also the reason why 10.5 has gone so high in price is the fact it's the last and latest OSX that will work on G4 and G5 Macs, so there is a large demand for it by owners of the Power PC Macs.