Test a iMac G5 logic board without Hardware Test?
My son's 17" imac PPC G5 was not booting up. After a trying a couple of things I got it to boot using Disk Warrior and reparing the file directory. At that time I also ran DW's hardware test which said the drive was fine. My son hard restarted it shortly after I fixed it and it wouldn't start up again. Just a gray screen, no apple logo. When I tried to use DW again it told me there were problems with the hard drive and it couldn't fix the problem. I tried to fix the hard drive in target disk mode using Disk Utiltiy and Drive Genius. No luck. So I pulled a working drive out of my Mac Pro and reformatted it and swapped the internal drive of the iMac with it. There were no DIP switches to set. Started up the imac with a Leopard retail disk thinking I would just install a fresh system onto the replaced internal drive of the iMac. Disk Utility on the leopard disk didn't see the hard drive. Now I'm beginning to think it's a logic board problem but I can't find the original disks to do a Hardware test with. Is there some other way to test a logic board? Or some other idea that I'm not thinking of that could be wrong with the machine?
Mac Pro, Mac OS X (10.7.4), ATI 1900, 8GbRAM