I love that you guys took a look at some retro tech, especially stuff I grew up working with. My aunt is a (now retired) teacher at a private Lutheran school and she helped run their computer lab. We had a bunch of these iMacs when they were new and I remember helping her take them apart for troubleshooting and repairs. And now I keep a few on hand for fun. There's also a Low End Mac group on Facebook that's pretty active. If someone would like to join, we'd love to help you guys find an LCD screen that fits in here and get your project going. Just please don't gut this one, use an iMac that's already dead.
But some error correction is in order here.
Apple didn't use a CMOS or BIOS on those computers, that giant 1/2 AA battery (yes, it's actually called a "one half double A") was for the PRAM (parameter RAM) stored for their OpenFirmware. Yeah, OPEN FIRMWARE! You could boot into it and change settings directly if you knew how. Apple didn't want you booting these machines from USB, but if you're skilled with OpenFirmware, it could be done. There's actually some debate over which brand of batteries is decent enough to replace these in our aging machines.
Next up, that CD drive is most definitely not SCSI. These computers don't use SCSI, not even externally. You can tell it's not SCSI because there's no jumpers or wheel to select an ID number. It's ATA (or PATA or IDE, whatever tickles your fancy) with a wider ribbon to carry some control signals and power, and then the narrow part below that is a normal width ATA cable for the hard drive. Apple System Profiler will show you a lot of good information about the hardware. While there were a few more that supported it, the last Mac to boot from internal SCSI (at least by default) was the Power Macintosh 9600/350. While the 9600 did run a PowerPC processor, it was older than the G3 in this iMac. And this wasn't even close to the last generation of PowerPC computers Apple put out. This was a model from about 2000, the iMac G4 and G5 were two newer generations that came out before the Intel transition to X86.
Finally, also relating to the slot load CD, you can eject it by sticking a straightened paperclip into the right side. Those drives die with age, we have a few workarounds and repairs we've learned for them to keep them running.
Now PLEASE come join us on LEM so we can help you with that mod!
