joeyslaptop Posted July 23, 2020 Share Posted July 23, 2020 (edited) Does anyone have instructions or schematics for the power board (820-1178-A) that comes in the PowerMac G4 case? I'm trying to keep my mod as vanilla as I can, and really want to be able to get the power button to work as it did originally. To use the front-panel speaker, I pulled apart a usb headset cable for the little sound card on it. Then I soldered the tiny sound card to a tiny USB amp card for a USB speaker. Then I wired that to the speaker. So, my front-panel speaker is powered off one of the USB headers of my motherboard. The components are tucked neatly away in the speaker casing. If I could have found a small 2-watt USB speaker, I could have avoided soldering multiple tiny boards together, and just removed the USB speaker from its card, and soldered the connections directly to the PowerMac's speaker. I'm willing to do something similar in order to get my power button and led to function correctly as well. Any ideas or resources you can point me to? I tried just matching up pins based on using a multimeter, but found that nothing is connected directly to the power button. I think this requires continual power, and then the power button sends a signal when you press it rather than a simple power interruption like a normal motherboard switch. I could be wrong though. I'm not scared to solder if needed, but would like to keep it as close to the original functionality as possible - even if I have to buy and mod additional components. (Note the the 2nd image is flipped to make it easier to see where things line up from the front to the back). Edited July 23, 2020 by joeyslaptop Link to comment Share on other sites More sharing options...
LiveSorcerer Posted September 14, 2020 Share Posted September 14, 2020 I have this power board, I will try find a photo with correct pinout for ATX Motherboard. Link to comment Share on other sites More sharing options...
joeyslaptop Posted November 9, 2020 Author Share Posted November 9, 2020 I got sick of researching. I'm sure I'll be unsatisfied with this method after awhile, but for now, it gives me the basic functionality I need (On/Off, reboot). Later, I can bridge the scratched gaps with solder if I find a way to restore full functionality. https://www.tonymacx86.com/threads/simple-power-hack-mac-g4-sawtooth.176909/post-2132821 I also found another board in another case I bought at a garage sale as a backup. Link to comment Share on other sites More sharing options...
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