Some time ago, I made a foolish impulse purchase of a second Power Mac G5 – my original machine was a dual 2.0 GHz model, the new one is a dual-core 2.3 GHz model. It arrived with a big cut through the power cable, so I couldn't even try to boot it until I sourced a modern replacement.
Once that worked, I was a good fraction of the way through getting it set up when, one day, it mysteriously died upon being turned on. After much investigation I determined that the apparently pristine power supply was in fact totally dead.
I recently got a replacement power supply off eBay, and after much finagling, it... still wouldn't try to boot, but now one of the three LEDs that is supposed to come on when the side door is open was working, so /progress had been made!/
After much poking and prodding, and extensive re-reading of the service manual for that model which is available in various places online, I took a chance on ordering a replacement front-panel power switch. Man, that thing is a NIGHTMARE to disassemble safely - the little circlip that holds it in is the kind that you have to pry out at one end, not the kind you can pinch with a special tool that looks like a pair of pliers with little pins sticking out of the side. Getting that pried out without severing the leads soldered to the tiny circular PCB behind the button is NOT easy. Further, if you buy a front panel switch it usually comes with the rest of the front panel, and surprisingly enough, there were three mutually incompatible designs for that (I had ordered one that didn't match my machine, but luckily, I only needed the actual button part, which was the same on all three designs).
The front panel board on the Late 2005 model, which I believe must be the last of the three designs, is electronically connected to the motherboard via a strange press-fit connection that involves 24 little spring pins in a DIP outline brushing against bare traces on the bottom of the front-panel PCB. Several of mine were mashed and probably not connecting properly. With care and no small degree of pure luck, I managed to bend them back into position without breaking any. (If you try to fix one of these, I cannot over-emphasize how fragile they appear to be.)
So after all that, I put it all back together and plugged it in... The LEDs now come on with the side panel open, though the last of the three does so reluctantly; and the red LED illuminates for about a second and a half whenever the machine is turned on even with the door closed – but IT WORKS! I have revived it from the dead! (Mostly. I think it's still got a little bit of a Living Dead aspect given that the trouble LED lights up whenever I power it on, but, hey, it's close enough for me!)
I hope my admittedly vague description of the power button's guts is helpful for someone – there's not much said about it elsewhere online. If anyone has questions I will try to describe it better.
Once that worked, I was a good fraction of the way through getting it set up when, one day, it mysteriously died upon being turned on. After much investigation I determined that the apparently pristine power supply was in fact totally dead.
I recently got a replacement power supply off eBay, and after much finagling, it... still wouldn't try to boot, but now one of the three LEDs that is supposed to come on when the side door is open was working, so /progress had been made!/
After much poking and prodding, and extensive re-reading of the service manual for that model which is available in various places online, I took a chance on ordering a replacement front-panel power switch. Man, that thing is a NIGHTMARE to disassemble safely - the little circlip that holds it in is the kind that you have to pry out at one end, not the kind you can pinch with a special tool that looks like a pair of pliers with little pins sticking out of the side. Getting that pried out without severing the leads soldered to the tiny circular PCB behind the button is NOT easy. Further, if you buy a front panel switch it usually comes with the rest of the front panel, and surprisingly enough, there were three mutually incompatible designs for that (I had ordered one that didn't match my machine, but luckily, I only needed the actual button part, which was the same on all three designs).
The front panel board on the Late 2005 model, which I believe must be the last of the three designs, is electronically connected to the motherboard via a strange press-fit connection that involves 24 little spring pins in a DIP outline brushing against bare traces on the bottom of the front-panel PCB. Several of mine were mashed and probably not connecting properly. With care and no small degree of pure luck, I managed to bend them back into position without breaking any. (If you try to fix one of these, I cannot over-emphasize how fragile they appear to be.)
So after all that, I put it all back together and plugged it in... The LEDs now come on with the side panel open, though the last of the three does so reluctantly; and the red LED illuminates for about a second and a half whenever the machine is turned on even with the door closed – but IT WORKS! I have revived it from the dead! (Mostly. I think it's still got a little bit of a Living Dead aspect given that the trouble LED lights up whenever I power it on, but, hey, it's close enough for me!)
I hope my admittedly vague description of the power button's guts is helpful for someone – there's not much said about it elsewhere online. If anyone has questions I will try to describe it better.
