Apple iMac G4

2021, Feb 06    

My love for older technology has always had a soft-spot for quirky designs, and the original iMac is no exception. With its round base, built-in monitor, and integrated speaker it was a revolutionary design at the time. After finally managing to acquie one in good condition, it was time to begin work on modernising the parts and restoring it to full health.

The Internals

It's safe to say that the device hadn't been opened in a very long time. Full of dust, heat-scorched ribbon cables, and a fan whose bearings had worn away a long time ago. While opening the device was simple (when you have the right set of screwdrivers), surviving the mountain of dust that comes out is a different story. Thankfully the internals were all in good condition and simply needed a clean.

Inside Dusty
This may have been dusty for some time...

The Changes

From a change perspective the main upgrade was that of the HDD-to-SSD change, as the additional RAM module (to take it to the unofficial 2GB max) was already fitted. The original plan was to keep the original device fan however the bearings had gone and so a new Noctua 92mm was ordered to replace it (even though it only uses two wires, a 3-pin fan will still work). It's worth noting however that the OEM fan has a reversed flow based on orientation, and also uses a reversed 3-pin connector (thankfully the Noctua fan comes with a 4-pin molex power connector that can be used instead).

Bespoke Fan
SSD's make all the difference

The new SSD was from OWC, specifically one of their compatible models for the iMac G3. One disapointment (in comparison to non-OWC models) is that its actually a SATA SSD with a converter board, rather than a SSD with a native IDE interface. While this doesn't make a negative difference to the overall performance (and it does improve compatibility), it does add an additional board to the mix which can get in the way. Thankfully (as expected) the SSD works without issue, at least with 10.4 (covered later).


Bespoke Fan
The original fan, replaced by a Noctua 92mm

Switching the fan out was definitely necessary given the bearing noise on the installed fan. Thankfully a 92mm Noctua fan fits just fine, however care has to be taken to ensure the orientation of the fan as the casing airflow direction differs between the OEM and the Noctua. Also, the fan connector is reversed and so it either requires a rewire or the use of the 4-pin molex connector. With the new fan fitted and new heatsink compound fitted (it needs to be done each time the full base is refitted), the system was ready for the new install of macOS.

macOS Install
The first macOS install (10.2), which took over 24 hours

With the new drive installed the first attempt at installing macOS was version 10.2, with the view being that once this was installed an upgrade to 10.4 would be performed. Unfortunately, this is where the incompatibility starts... Not only did the 10.2 install not see the additional 1GB of RAM, but what should have taken no more than 2 hours took over 24 hours. Worse, once installed you would constantly see the pinwheel whenever you tried to open an application (not to mention it takes over 10 minutes to fully boot). Thankfully a reinstall using the 10.4 media worked without issue and at full performance, taking less than 30 minutes overall.

Full credit to Apple at this point, as despite the system being many years old and running an OS that is now completely unsupported, the system updates to take it from 10.4 to 10.4.11 are still available and install without issue, despite the multiple SSL/TLS changes over the last 10 years. As an added bonus, 10.4 is also able to recognise and use the additional 1GB RAM.


The Result

A stable G4 iMac running macOS and performing incredibly well given its age. It's able to access the internet (using Safari) and runs without issue after many issues of CPU burn-in (to test the new fan and the heatsink compound). While not able to run modern macOS applications, it's still a great classic to showcase the unique design and earlier macOS version.

macOS Installed
The second macOS install (10.4), installed and updated