Replace Power Macintosh G3 Beige mini tower PSU with a new ATX PSU?

GVD

New Tinkerer
Dec 23, 2021
8
9
3
Hi all,

I want to replace the power supply in my beige G3 mini tower. The computer was literally a rats nest when I bought it. It cleaned up nicely. I “repaired” some wires with chewed up insulation on the power supply with electrical tape and has been operating fine as far as I can tell. Though I did have some issues recently when I tried installing a DVD-RW drive. Since I keep upgrading and plan on adding a G4 from a YIKES Power Mac, I figured it might be a good idea to have a reliable power supply.

Currently, it has a Rage 128 graphics card, sonnet USB/FireWire combo card, and a SeriTek/1S2 PCI SATA card.

I purchased a new ATX power supply on Amazon but it present two issues:

1. The fan on the power supply sits almost up against the access panel when it’s closed. This is an issue for air flow. It looks like every new ATX power supply has the same issue.
2. The power connector for the case fan is a 2 pin female connector that attached to the male connector on the original power supply. Is there a 2 pin female to molex adapter? I have a molex to 2 pin male adapter, but it’s of no use in this situation.

Has anyone else done this swap recently?

I had one other idea, I purchased a dead PSU from a Power Macintosh G3. I want to open it up and remove the internals, except for the fan. I was thinking about installing the internals from a new PSU and utilize the original PSU's fan.

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GVD

New Tinkerer
Dec 23, 2021
8
9
3
Update in case anyone is looking to replace their PSU with a modern ATX one. I used this ATX2G3 Conversion Cable, 20-pin male to 24-pin female extension cable from Kero's Mac Mods. You don't need to use one of these, but I liked how Kero added the wire for the case fan. If you are halfway decent at rewiring things, I think you can make this on your own. Everything works great. The fan runs quiet and the PSU stays cool. If I could do anything differently, I would have purchased a modular PSU. There are a lot of unused harnesses that you need to tuck away otherwise.