Upgrading a
Macintosh iMac G3

The original iMac is credited by many as saving Apple. It was a very cool design for it's time and brought back the all in one design that originated with the first Macintosh 128k in a modern package. It also introduced new technology such as USB but at the same time removing the venerable but antiquated floppy.

We own several generations of iMacs the other distinguishing feature of the original iMac was this covered slot known as the Mezzanine slot. It is believed that this was used by Apple to test and troubleshoot the motherboards.

The next version of iMac did not come with the mezzanine slot nor did any further versions.

The Bondi and second generation iMac G3 had their cpu on a daughtercard. This meant that the 233 mhz and 266 mhz cpu's could be replaced with the 333 mhz cpu very easily. Also note that there was a second memory slot on the underside the cpu daughtercard.

Just pull it up and out of the metal cage.

There seems to be some debate as to whether you can use this plug to add in another monitor, if that information stamped on it is correct it doesen't seem like it granted I haven't experimented since this iMac is in good shape and the only one I have of this model in my collection so I don't particularly want to fry it just to find out for someone else.

This is the cable running into that plug.

On this generation of iMac G3 memory expansion couldn't be easier, just turn the knob and open the door to expose two 168 pin dimm slots.

This particular iMac is happy with PC 100 or PC 133 dimms up to 512mb per dimm. Earlier iMacs used SODIMMS so you should double check what memory your iMac requires before ordering it.

The base can be removed allowing you access to the motherboard, optical drive and hard drive.

As mentioned above not too many user replaceable parts other than the 1/2 AA battery used for PRAM backup. I do notice that this G3 350 mhz motherboard is similar to the 400 mhz version with Airport slot and firewire. I have not tried to swap the parts as you would need the motherboard and trim for the ports on the side.

What is interesting is that the metal trim behind this plastic cover has the cutouts for firewire ports.

Just plugs right into the motherboard, also looks similar to the one in the 400 mhz with firewire.

This is the caddy which holds the hard drive and the CD drive.

At first glance it looks like the optical drive is a standard laptop drive, it isn't. May work if you had a mounting adaptor though.

OEM drive is a slot loading CD/RW drive.

Comments? Feel free to e-mail me at kevino@newsroom.net.