I have replaced the capacitors on three G5 iMacs, both on the logic board and in the power supplies. I got my capacitors from Jim Warholic (Google his name), who also provides lots of advice and tips. There are other sources of advice and caps online, at least one of which says Warholic is full of, er, stuff. Ain't free speech and democracy wonderful?
I was able to bring back to life only one of the three G5 iMacs. All three were pre-iSight models, meaning either first-gen or second-gen ambient light sensor. Both of the failures (a 20" 1.8 GHz and a 17" 1.6 GHz) had ceased chiming or even trying to boot before I got them. Replacement of all the caps on the logic boards and in the power supplies succeeded in getting the second diagnostic light to come on, but not the third, and in getting the hard drive to start running, but that was all. Both of the power supplies were brought back to life. My assumption is that the logic boards had suffered irreparable damage that new caps could not reverse. The third one, a first-gen 1.8 GHz 20-inch model, is running perfectly as this is written. It was still trying to chime and boot when I got it, even though the screen went nuts and froze after about 15 seconds after it lit up. I replaced all the caps on the logic board and in the power supply. The first go-around, it initially booted and ran perfectly, but when it warmed up it started throwing occasional video glitches and kernel panics, as well as beeping 3 times on restarts. I took that as evidence that I had not done a very good solder job. So I removed the logic board capacitors, cleaned out the holes thoroughly and carefully reinstalled the caps. That worked, and it's now a very stable machine. The most difficult part -- aside from my steep soldering learning curve ascent -- was removing the original capacitors. Apple used lead-free solder in those iMacs, and I literally burned up several solder guns of increasingly higher heat capacity before I got one that could melt the original solder enough to free the bad caps. I even had to use a tiny drill chucked into a Dremel tool to clean out the holes; I used hand power rather than the 10,000 or 20,000 rpm motor to avoid doing damage. So be aware that your toughest part of the job is going to be removal of the original caps without damaging the boards. The second-toughest part is doing a satisfactory solder job on the new caps. For some reason, those iMac logic boards do not like to be resoldered, Perhaps its the whole original lead-free thing. All I can say is that the same technique and tools I have used many times to replace flyback transformers on G3 iMac PAV boards do not work the same way on iMac G5 logic boards. Good luck! Jim Scott -- You received this message because you are a member of the iMac Group, a group for those using Apple iMacs and eMacs. The list FAQ is at http://lowendmac.com/imac/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] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/imaclist To unsubscribe from this group, send email to imaclist+unsubscribegooglegroups.com or reply to this email with the words "REMOVE ME" as the subject.
