On Aug 25, 2011, at 2:10 PM, Iamanamma wrote: > I've got a 20" iMac G5 2Ghz that is behaving oddly. > > When you turn it on, it starts up, chime and all, finds the system > folder, and proceeds to the gray Apple screen where the start-up > animation spins for a few seconds like normal, then the screen turns > blue and the finder refuses to load. The cursor usually comes up and > I can move it around with the mouse, until the start-up animation > shows up again and start spinning, and spinning, and spinning... > > If I leave it on long enough, sometimes the fan will kick on in high > gear, but not always. > > I tried booting from a DVD, and I get the same behavior. Zapping the > PRAM had no effect at all. I opened the case, blew out the dust > bunnies and checked for bad capacitors. The capacitors all look > healthy. I've had enough of these particular iMacs have caps go all > bulgy, so I was pretty sure I'd find the problem there, and was > surprised when I did not. I did not notice any odor coming from the > power source, but I did not remove it to look for evidence of bad caps > in the power source. I'm not getting the usual symptoms of a bad > power source (won't turn on , turns itself off intermittently, fans > blowing loudly ALL the time), I just can't finish the startup > sequence. > > Any ideas?
It's freezing (with moving cursor) right at the point the OS is making full demands on the video circuitry. It could be heat-related (clean out the dust/bunnies; check that all three fans work). Or it could be that the logic board needs to be removed so you can replace the Northbridge heat sink thermal paste which may have dried out. I wouldn't touch the cpu and gpu thermal pads. I fixed a similar iMac G5's flaky behavior, which was similar to yours, simply by cleaning everything inside the case and redoing the Northbridge thermal paste. Good luck! Jim Scott -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g3-5-list
