So, I received the replacement logic board today, installed it, and now the iMac starts up as expected. I still have a video problem, but that is because the replacement LCD screen I ordered is bad. At least the old one still works now, multi lines and all. So somehow I must have injured the logic board when I originally installed the replacement LCD screen. I am definitely more careful handling all the parts now. Learned a bit about troubleshooting iMacs, so thanks again for all the communications. Guess I'll close this post. Thanks. Ron

Follow-up to this post.....I installed a replacement LCD screen, and now the Ipad3 works as expected. Guess I should have suspected that to begin with, but it sure didn't appear to be the typical Ipad screen issue, with the chiming and all. So...thanks for the replies and the suggestions.

Majesty, you have been so helpful and patient, and I appreciate it. I finally resolved the problem! Apparently, I had a couple of issues going on, and led myself down the wrong path with a logic board replacement. I put the old logic board back in and confirmed I still could not install OSX 10.3....however, I now believe that is because the disks I bought were not the retail version that was advertised. Then, with the borrowed iBook that has OSX 10.5 installed, I cloned from it to mine via Target Mode. This time I let the clone finish to completion....before, I think I ended it before the verify was done, as I thought it was complete. Lo and behold....both Mac iBooks now run flawlessly with OSX 10.5. So, this has been a great learning experience for me with Macs. I did not realize the difference between the install disks that originally come with a Mac and the Retail versions...and the impact they can have on installation. Guess I was using too much Windows mentality. Still find it interesting that you...

I tend to agree with the logic board(s) conclusion, however one thing puzzles me. When I cloned the "good" OSX (onto a new HD), I could not use the cloned copy in either machine, although the clone appeared to work A-OK, and was identified in the cloning process as bootable. However, the original "good" OSX works in both machines...it just freezes in the problem machine. That makes me wonder if there may be some weird Apple kernel related issues with trying to run the "good" OSX in a machine it was not originally installed on. I'm thinking I might put the original logic board back in, and try to locate a copy of 10.4 install disks. Not giving up yet!

Well, I'm back and still unresolved. I bought a used iBook G4 14" A1055 (identical to the problem machine) and verified it works as designed. So, I attached the problem machine to it in Target Mode and did a disk clone. Still no go. Next I took the hard drive out of the working machine and put it in the problem machine, and lo and behold, it booted up. Unfortunately, it will only run a few minutes, then it freezes with no cursor activity or anyway to get it going except a power reboot. I'm surmising this points to a logic board problem. I'm going to put the original logic board back in it and see if that makes a difference. Still cannot get it to start up from any install CDs. More later.

Majesty, I'm inclined to agree with you on the logic boards, although I hate to believe someone would sell a known failing item advertised as working. If I can get a good iBook, I will be able to verify what is failing. Now it has become a challenge to figure it out. Once again, thanks for the help. Ron

Well it doesn't see the USB optical drive at startup either. Since it does not start up with a OSX install CD, whether there is a HD installed or not, doesn't that indicate something other than a HD problem? I think my next step is to see if I can get my hands on a working iBook to compare things with. Hopefully, that will help me zero in on the problem. I really do appreciate the help, and will post back if I learn anything useful. Thanks.....Ron

I disconnected the optical drive cable and tried booting up. The HD spins, the screen lights up, and it sits with small flashing folder in the middle of the screen, which alternates between a ? and a happy face icon. I tried this with no keys pressed and with the C key pressed, same result. If I leave the optical drive disconnected, and connect a USB optical drive, do you think it would try to boot from that? I've already tried booting from a USB HD, that has OSX 10.4 on it, and it does not recognize it.

The CDs appear to be clean and scratch free. The external drive powers up, but there does not seem to be any recognition of it. This is a USB connection...is that OK? I am working with only the AC Adapter, no battery, but have tried the power drain. Yes, when I copied the OS from another Mac, I did selet the bootable option. Another bit of info I just learned, based on an earlier comment about the HD cable. I examined it and it appears OK and connected well. Out of curiosity, I unplugged the cable from the logic board, and tried a few different start-ups.....they all gave the exact same results as the start-ups tried with the cable connected. That suggests it is never getting to the hard drive. Also....when booting from the CD, I never get the spinning wheel with the Apple logo....just the logo, then it moves a couple of pixels on the screen and freezes. I can hear the CD drive spinning....so maybe I have a bad CD disk?

Thanks. I tried both the SAFE MODE boot and the Boot From External Drive boot. Both ended with the universal "NO" symbol after the Apple logo was up for a few seconds. The Alt key boot did not show any drives at all. I inserted the OSX CD and tried the Alt Key boot again, and it showed the Optical drive. I selected the Optical drive and booted from it, and got the usual frozen Apple logo after several seconds. Interesting that it does not seem to recognize a hard drive at all, internal or external, but does recognize the optical drive. I had a loaner Macbook a few days back and did a Target boot with it. It did show the iBook hard drive, so I copied the Macbook OS to it, hoping that would make it bootable....but I continue to get the same results. Question.....should the machine normally boot up from the optical drive even if there is no hard drive installed? If that is the case, then I am beginning to wonder if the problem is with the optical drive "or" the install CDs.