Power light is on, but no response from G5 tower

Hi,

Our G5 Power Mac was in sleep mode over night a few days ago. The power went out during the night sometime and came back on about 2 hours later. Both our Mac Book Pro and G5 were in sleep mode, the MBP is fine, no damage at all. However, the power light on the front of the G5 is on, but the computer is not on, the external hard drives are off and the monitor wont come on. I tried to hold the power button down to shut off the light, but nothing happens no matter how long I hold it. The only way to make the light go out is to unplug it from the wall.

After I plug it back in, the light instantly comes on again by itself and the Mac just sits there doing nothing. The G5 is on a surge protector if that helps the diagnosis.

Thanks in advance for any help.

The G5 may have suffered damage to its power supply from the power off, power on, during the night. Power surge strips (no matter how sophisticated) do not provide adequate enough protection from power hits and line surges. In some instances they may mitigate it somewhat, however, the best protection is an isolated UPS system.

Your machines were in sleep mode which means they were still on but in low power state and vulnerable to line hits.

See if this trouble shooting article helps: LINK

Regards.

Thanks for the link, however I didnt see anything there that sounded like my problem. They had some info on power supply problems but the users were experiencing fan noises, mine is dead quiet with the front light on and thats it, nothing else works.

Might be time to make an appointment at the Genius Bar. I just hate to spend anymore money on this old G5 tower.

Unplug the G5 from the wall again, but this time leave it off for several hours.

Secondly, open up the G5 while it's off, and replace the PRAM battery (not a big cost). If I were you I'd also pull the RAM modules, and then reseat them firmly. Again, wait for an hour or two before trying a restart.

Thank you, I'm trying it right now.

A quick update. Its working perfectly again. A friend suggested taking the cover off and pushing the PMU reset button on the logic board. Did that and it fired right up when I plugged it back in.

Thanks again

Jumbo Jet said:

A quick update. Its working perfectly again. A friend suggested taking the cover off and pushing the PMU reset button on the logic board. Did that and it fired right up when I plugged it back in.

Thanks again

Click to expand...

Congrats! Hopefully everything will remain stable.

- Nick