Hi,
I just recently got a beige G3 desktop, but the power supply seems to be dying. I heard that these support ATX PSUs but I'm still not entirely sure. I read on one site that you need to change some wires, but on another it says it'll work fine without any mods.
Checking the pinouts, pin 18 on ATX is -5V while on the Mac it's GND. Modern PSUs don't have -5V anymore and my G3's PSU doesn't have a wire going to pin 18 either, so I'm guessing that's fine?
I've also heard that pin 8 might be +3.3V on some Macs? This is where I'm unsure. The service manual says pin 8 is POK though, which matches ATX. Oddly the G3's PSU doesn't have any wire going to pin 8.
Also, AFAIK the minitower and desktop have different PSUs and use a jumper to select between the two. How do the two PSUs actually differ and what does the jumper actually do? Since the jumper is near the reset button maybe it has something to do with POK?
Sorry if this has been asked before, but I wanted to clear a few things up before giving this a try.
ATX pinout:
![atxpinout.png]( "atxpinout.png")
G3 pinout:
![g3pinout.png]( "g3pinout.png")
I just recently got a beige G3 desktop, but the power supply seems to be dying. I heard that these support ATX PSUs but I'm still not entirely sure. I read on one site that you need to change some wires, but on another it says it'll work fine without any mods.
Checking the pinouts, pin 18 on ATX is -5V while on the Mac it's GND. Modern PSUs don't have -5V anymore and my G3's PSU doesn't have a wire going to pin 18 either, so I'm guessing that's fine?
I've also heard that pin 8 might be +3.3V on some Macs? This is where I'm unsure. The service manual says pin 8 is POK though, which matches ATX. Oddly the G3's PSU doesn't have any wire going to pin 8.
Also, AFAIK the minitower and desktop have different PSUs and use a jumper to select between the two. How do the two PSUs actually differ and what does the jumper actually do? Since the jumper is near the reset button maybe it has something to do with POK?
Sorry if this has been asked before, but I wanted to clear a few things up before giving this a try.
ATX pinout:
G3 pinout: