A couple of things I forgot to mention regarding logic boards. If you have a Rev. A through Rev. D G3 iMac logic board, theoretically you can mix and match the boards. For example, a Rev. D board could be installed in a Rev. A model, boosting the speed by 50 to 100 Mhz. Somebody correct me if that is accurate. The slot loading G3 iMacs (350 to 700 Mhz) I'm 100 percent sure they can be mix and matched. But make sure the models you are swapping logic boards out of use the same P.A.V. board.

Another tip, just above that door, you should have a perforated blanking plate, to gain access to a vga output (if available, as not all are supplied with)
try to connect a screen and fire the Imac, an upgrade to Mac Os X without loading the proper firmware tends to disable the inner screen.

A firmware upgrade (from a HD and 9.2 Os) solves the problem.

Click to expand...

Not all slot-loading G3 iMac logic boards have external VGA out. I have a 400 Mhz board that came with an MPEG codec card, but no VGA out, whereas the 500 Mhz board that replaced it had the opposite (1 VGA out, no MPEG board). It would've been nice to add that MPEG card, but the new board didn't have the connector soldered on. I would have to desolder it from the old board and resolder to the new board.

I agree with regards to installing OS X without the right firmware upgrade applied. Double check that you have version 4.1.8f4 installed. If not, boot into OS 9.x, download the firmware update from Apple and you should be good to go. You may have to reinstall OS X as well, but you don't have to lose anything. Do a clean install and it will still retain the users and user data; it will only install a clean system folder and your old folder will be turned into the "Previous System Folder". From there, reinstall the software updates, move the preference files into the new System folder and you're good.

73s de Phreakout. :rambo: