sabbertonic
Registered
I have a Power Mac G5 Desktop 2Ghz- M9032LL/A serial number XB4060FBNVS. I bought it June 26 2004.
I use a power strip that I turn off after the computer shuts its self down.
The failure mode that has occurred before and now seems permanent is:
Power strip on. I hear the relay in the computers power supply click on then off.
Push power button: it lights up while I'm holding it but it does not stay lit. I hear the fans come on and the hard drives spin up BUT no chime and no display.
I hold power button 5 sec and it powers down.
I measured the internal 3.6 volt battery in circuit at about 3.5 volts. Since it was the original I replace it with a new battery that I pretested under a 1ma load. The unit powered up normally and I reset the clock. Had a normal 4 hour session with no problems. Next day it was back to the same power up problem. I verified battery voltage at 3.6 volts in circuit. Tried several power up /down cycles.
I tried to reset Pram
I reset the PMU as instructed on MAC site. Same problem.
On the my test bench with nothing connected it repeated these same symptoms. After several attempts I did get it to chime 2 power cycles in a row but I did not have a monitor hooked up. So I powered it down by holding the button 5 sec. When I hooked up the monitor and rebooted it failed to chime. I removed the monitor and it has failed to chime since then.
I have removed both hard drives and replaced them with a spare. I have tried to boot up with no hard drives. No change. The power supply is obviously not totally dead but maybe one of the voltages is intermittent? Plug 1, pin 1 of the power supply does have 5.1 volts in standby mode. Does this sound like a logic board problem?
I have tried reseating the video card and RAM.
This is my main music studio computer and I need it to work. Any help would be greatly appreciated.
I use a power strip that I turn off after the computer shuts its self down.
The failure mode that has occurred before and now seems permanent is:
Power strip on. I hear the relay in the computers power supply click on then off.
Push power button: it lights up while I'm holding it but it does not stay lit. I hear the fans come on and the hard drives spin up BUT no chime and no display.
I hold power button 5 sec and it powers down.
I measured the internal 3.6 volt battery in circuit at about 3.5 volts. Since it was the original I replace it with a new battery that I pretested under a 1ma load. The unit powered up normally and I reset the clock. Had a normal 4 hour session with no problems. Next day it was back to the same power up problem. I verified battery voltage at 3.6 volts in circuit. Tried several power up /down cycles.
I tried to reset Pram
I reset the PMU as instructed on MAC site. Same problem.
On the my test bench with nothing connected it repeated these same symptoms. After several attempts I did get it to chime 2 power cycles in a row but I did not have a monitor hooked up. So I powered it down by holding the button 5 sec. When I hooked up the monitor and rebooted it failed to chime. I removed the monitor and it has failed to chime since then.
I have removed both hard drives and replaced them with a spare. I have tried to boot up with no hard drives. No change. The power supply is obviously not totally dead but maybe one of the voltages is intermittent? Plug 1, pin 1 of the power supply does have 5.1 volts in standby mode. Does this sound like a logic board problem?
I have tried reseating the video card and RAM.
This is my main music studio computer and I need it to work. Any help would be greatly appreciated.
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