I want to confirm that you switched CPUs (A in B slot and B in A slot) and that they were both seated properly when you turned the computer on. If CPU A is bad and CPU B is good putting CPU B in the A spot and CPU A in the B spot should allow the computer to boot. Both CPUs (even if one is bad) need to be installed for the computer to work. When I was fixing my problem I had both issues (unseated and only one installed).
One of the earlier G5s was able to run with only one CPU installed in a 2 CPU system so you could try that, but I think it was an earlier model to yours. Have you replaced the battery? That can be the cause of various issues. I do not know of any motherboard checks except for visual inspection of bad capacitors. If the computer is making sounds and the fans eventually go into wind tunnel mode I would think the power supply is probably okay. The chance that BOTH processors went bad at the same time seems slim. So, I would guess logic board. I fixed mine on a whim just to see if it was possible before getting rid of it. These computers are so cheap now that it is almost not worth the time/effort to repair them. This is the store<http://www.electronicscafe.com/> I purchased my parts from. They also sell on ebay. They have a motherboard that might work for about $17 and a pair of cpus for $25. -- 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
