Upgrading a
Macintosh iMac G4

The iMac G4 with 15" LCD monitor was a radical departure from the all in one Macs Apple had previously released. Sporting a fast G4 cpu and 15" LCD monitor a first for the iMac line it was a very fast and capable computer and even today (2008) is a solid performer.

To access the internal components of this iMac you have to first remove the base plate that is held on with 4 screws. These screws by the way are not fully removeable.

With the base plate removed you have access to the lower memory slot as well as the slot for an AirPort card. Removing the 4 torx screws allows you to gain access to the upper memory slot and the internal components of the iMac.

To gain access to the internal components you have to gently pry the two parts of the base apart. Be careful as there is a power and ribbon cable as well as the video and another power cable holding the two halves together.

To get easier access to the upper portion of the iMac you need to unplug the ribbon cable and the power cable in this photo. Also note that Apple uses a thermal paste on the heat pipe which is visible in the top right corner of the base containing the motherboard. You must reapply this paste when you put the iMac back together.

The upper half of the motherboard has a second memory slot which is populated with a 168 pin dimm. You can install a PC 133 512mb dimm in this slot. Also note the 1/2 AA battery location.

The dome of the iMac contains the power supply as well as a caddy that holds the CD/RW and hard drive. To remove the CD and hard drive 6 torx screws need to be removed and the caddy gently removed from this structure. Don't force anything as there is a lot of wiring running nearby that could be damaged.

This is the caddy which holds the hard drive and the CD drive. I replaced the original hard drive with a 120 GB version which is the maximum size this Mac can access. Low End Mac does report on their website that iMac G4's can see all the space on larger hard drives if you run OS X 10.2 or newer. I have not tried this yet even though I am running 10.4 on my iMac. http://lowendmac.com/macdan/05/1024.html

I replaced the original DVD/CD RW drive with a Pioneer DVR 115 which is a dual layer DVD writer. This drive is slightly smaller in length than the original but fits nicely and works perfectly.

The only trick to installing an aftermarket DVD writer is that you must remove the trim on the tray and faceplate in order for it to clear the small slot on the body of the iMac. Still a very simple fix and installation.

I have encountered a problem with my particular iMac and it has to do with problems with the LCD screen. When the iMac boots up the screen brightness is too high causing the screen to look totally washed out. I can dial back the brightness to a useable level but it means I cannot reliably edit photographs. This is caused by the LCD going bad as replacing the cabling and inverter do not solve the problem.

Another weak link can be that nice chrome arm which can wear out and become loose as well as the cable that run through this arm. Overall though this is an extremely cool looking Mac, one of my all time favourites.

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