grahamlee's Journal: iMacs in bits

I had to poke around in a couple of fruit-flavoured G3 iMacs today, as neither was booting properly. The inside of the iMac is a pretty interesting place, so here's a quick detail of what I did should it be interesting to anyone else. Needless to say, if you're not comfortable pulling computers apart, working with mains equipment or near the potentially fatal voltages found in the Cathode Ray Tube [see below], don't try this.

The first thing to do was to prepare. I found the Service Manual on the web, which contains troubleshooting and take-apart information. This is not quite indispensable, but gives you a good idea of what to look for. Read the take-apart section before you start working, so that you don't have to keep stopping and looking back.

Place the iMac face down on an anti-static mat, taking all the usual anti-static precautions. On the bottom near the back is a single screw in a recessed handle. Unscrew this (it won't come out though), and give the handle a good hard tug to get inside the case.

The good news is that if you just want to access the logic board, memory or drives, you don't need to go anywhere near the CRT :-). Just below the bit where you removed the cover are two screws clamping a bit of metal onto the plastic case. Unscrew those, and detach the four cables that plug into the area where the disks are. Now just pull upwards, and you're holding pretty much the whole computer in your hand. Be careful: the CD-ROM drive has a habit of sliding out of place (but can just as easily be slid back in).

That was the easy bit :-). Getting it back together is a bit trickier; my colleague and I collectively spent about an hour prodding, pushing and shoving until the logic board chassis went back into the case. Place the chassis at the top of its 'run' back down into the machine, and let it freely glide as far as it will go. Now you need to grab both sides of the outer case and pull outwards slightly, so that the chassis comes forwards (away from the machine) and downwards (toward the screen). It will then fall relatively smoothly into place.

Coming soon: PRAM battery replacements and software upgrades :-)