Disclaimer: This page is for entertainment only and is not guaranteed accurate. Performing modifications or other work inside your Mac will void any Apple warranty, may cause damage to your computer or result in personal injury. Although Ian indicates he made these modifications successfully, neither the site publishers nor the author warrants any of the information listed here. You assume all risk from the use of any of the information in this article.

IMPORTANT NOTE: This article used the motherboard from the original "Sawtooth" pre-summer 2000 (pre-Gigabit G4) model. Later models (Gigabit G4, Digital Audio, Quicksilver and later) have a different power supply and motherboard that passes 28 Volts DC from the power supply to a connector for the ADC port graphics card. (28 VDC is passed to the Graphics card ADC port to power Apple's ADC monitors, introduced at the Summer 2000 MacWorld NY Show.)
A standard PC ATX Power Supply does not have 28V DC and will not be pin compatible with the Gigabit G4 and later Macs. I wanted to clearly note the ADC/28V issue for anyone thinking of using a standard PC ATX supply for a conversion with the summer 2000 and later Macs. And unlike earlier G4s, the Mirrored Drive Door G4 uses a non-standard form factor power supply and will NOT fit in most ATX cases. (You can sometimes find Gigabit/Digital Audio and Quicksilver Power Supplies for sale at Ebay.)

Step #1 – Find the right case

Figure 1 ATX case with power supply installed

This was the case I chose to use. It was cheap and has fairly good expansion capabilities. I picked it up at my corner computer store for $50 (not bad at all). Now when you buy your case make sure you have lots of room for the Macintosh motherboard because they are different from their PC counterparts. I would recommend you take out your mother board from your Mac case first and measure it carefully, or measure it in the case, your choice, just make sure when you get the case your board will fit.

Step #2 – Drilling/Mounting Motherboard

All right this was the fun part. The Macintosh Motherboard is not ATX compatible so the holes that are pre-drilled and tapped on the case you have just bought will not work with your Mac board. You will need a good drill, a decent vacuum and good drill bits. Perhaps a tap and die set if you want to tap the holes you drill. Take your Motherboard out of your old case if you haven’t already done this. Now make sure you have at least one card in the expansion slot so as to get it lined up. I did not do this the first time and drilled the holes incorrectly. I couldn’t get in my expansion cards!

Figure 2 Test fitting an expansion card before drilling holes

Now place the motherboard in the correct position in the case and mark the holes.

Figure 3 Correctly positioned motherboard

Take out the motherboard and drill the marked holes out with a drill bit of the appropriate size. Now you have a choice of using the tap here and tapping out the holes or you could use a nut and bolt like I did.

Figure 4 Holes drilled and nuts on.
Notice a few “test” holes are present.

I used the supplied, little, plastic, stand-offs that came with the case to keep the board away from the back of the case. This will also give you the correct offset from the back of the case for the expansion cards etc.

The next page deals with the ATX Power Supply Connector.