So my latest insane attempt at building yet another Mac is taking the logic board from a 1.25Ghz G4 iMac (the 20" screen one) and placing it in either a PC case or a gutted Digital Audio case. I have all the info I need for the project except how to hookup an ATX power supply to this puppy, if that would even be possible. I don't have any other parts from the iMac as I bought the board all on its own and have gathered other needed parts as I come across them (VGA converter etc.) but don't want to shell out another $130+ for a stock power supply as that would bring the total cost too high. Anyone have any ideas, or even the pinout for the iMac's power supply so I could fool with it myself?
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iMac G4 project
- Thread starter eire3678
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This sounds like a good project to inquire about over at Applefritter. There's most likely someone there that has done something like this at one point, and they can provide you with any information that you need along the way.
ATX Wiring
Here are some service manuals - you may find it here.
Service Manuals 1
Service Manuals 2
Here are some service manuals - you may find it here.
Service Manuals 1
Service Manuals 2
Mechcozmo said:
Yeah, I've already got a VGA converter for the video out. As far as I can tell all I should need to do from here is power it and cool it. Cooling I've got covered, I'm going to fabricate my own heat pipes/fans solution that should be way past what was possible in the original form factor, hopefully allowing some good overclocking on the G4 and 5200FX. The system had a 160 watt power supply but I'm aiming for at least 300 as I'll have more drives then the stock configuration.
Simie, good sites but still not what I need, or at least I didn't see it. I need a pinout for the iMac's power supply so I can figure out how to hack apart an ATX supply to power everything. I do know it requires alot more +12V leads than most power supplies have so I'll have to get creative. This is what I had figured out from all the photos I could dig up back before the project landed on the shelf for a few months:
It seems Apple likes to use photos from different systems in their service manuals and pass them off as USB 2.0 iMac docs. I've seen both 14 and 16 pin power supplies in the PDF. The board I have has a 16 pin hook up.. Using Apple's 14 pin grid, I've come up with a ground in pin 1 and +12v in 8, 11, 12, 13 and 14. Examining what photos I could find of a 16 pin hookup I found +12v in 9-12, 14 and 16, +5v in 15, -12v in 13, and a ground in 8. It seems that the +12v in 16 and the +5v in 15 run off to power the optical and hard drives inside the iMac, they may not be direct from the power supply, just leads off the same hookup on the motherboard (does that make any sense?). I know there are more grounds and at least one -5v lead, possibly more of all kinds, however I haven't been able to determine where they would hook up on a 16 pin power supply. Anyone have any feedback on those ideas? To get pin numbers I used the ATX style of numbering 1-8 as the lower row and 9-16 as the upper, with the clip being on the upper side.
http://www.lbodnar.dsl.pipex.com/eServer/index.html
In this conversion article the eMac also has a 16 pin power supply hookup. Could the iMac have the same pinout or am I just off my rocker?
In this conversion article the eMac also has a 16 pin power supply hookup. Could the iMac have the same pinout or am I just off my rocker?
Mechcozmo: Thanks for the link but I already had it. There aren't any details in there that can help me beyond what I've already figured out (which assumes Apple used the same color coding as ATX power supplies). In fact I used those pdfs to decipher most of what I have.