Over a decade ago, I purchased a Power Mac G4 Mirror Drive Door (MDD) when I wanted to build an “Ultimate Mac OS 9” device. It’s been dead. Marchintosh 2025 is the perfect excuse to get it back online! And to return to the blog after… 7 years!

My poor MDD stopped working back in 2013- pressing power returned no solid lights, and I could not get it back to operating. So the MDD got shoved into a closet. I knew the PSU was bad, and that the Internet as a whole noted that your options were to buy a working old unit, repair the unit, or purchase a repair service.

In 2025, a member of the local Apple User Group (yes, they still exist!) reached out to my father on potential repairs for her MDD. With two MDDs in need of the same repair, and one belonging to someone other than me, there was enough reason to actually go ahead and see what can be done.

So I finally decided to pull the trigger on the MDD repair service offered by ACX Electronics at a cost of ~$330 (140 for each PSU, plus shipping, plus tax). The seller offers a $35 refund per returned power supply, so when I process that return, the cost will only be ~$260 to bring two devices back online.

NOTE: This equipment was purchased myself and this is not a sponsored advertisement.

So when I received my two PSUs, I got to work replacing the old units. On a MDD that has never been worked on inside, you will find a number of screws to remove (one holding the PSU to the side, one for the HDD area, two for the DVD area) as well as one hex key screw on the outside of the unit.

Removal took 10-15 minutes to get inside the device- more of less depending on screws and internal goodies in the way. For example, the user machine I started with had all the screws, but only one drive. For my machine, most screws are missing, but there are a number of extra drives that needed to be removed.

Once all the blocking bits of metal are removed, you can pivot the PSU out and remove the cable runs (it’s a bit tight!). Then you install your replacement PSU and return the cages and cables to where they came from.

At this point, I turned on the user device and – to my surprise – we reached Mac OS X’s login screen! The machine lived!

Next, I moved to my MDD, which was a bit tougher cause of extra cables (like the zip drive extension cable), but it too booted up once all put together.

The poor thing had been offline since 2013- but is now back online! I look forward to playing with it more and putting it through some workloads in 2025. My main goal will be to migrate away from spinning hard drives to SSDs.

The MDD now joins my other Mac OS 9 Ultimate machines- a TiBook 1GHz (that runs my Hotline server), a Mac Mini 1.5GHz (running Mac OS 9 using the unofficial support method), and UTM Virtual Machines.

While Kiwidget has always been a simple blog, I did take video of the work! If you are bored, you can watch the swaps below:

#MARCHintosh Event Logo concept and design by Javier Rivera | YouTube: https://www.youtube.com/c/JavMaster | Twitter: @javmast3r