Mac Pro G5 Dual 2.0Ghz - Plug In To Power and Get Eternal Clicking From Power Supply

[nj_computer_repair]

Pretty sure this is a bad power supply but just checking to see if anyone had a similar issue. The computer is a Mac Pro dual 2.0Ghz. When you plug in the power cord, you get the normal click that the power supply makes for this computer, but then it clicks again and again. This is without even pressing the power button on the front. The computer does not respond to any buttons although if you press the reset button on the motherboard and hold it, the clicking stops - only to start up again as soon as you let go. The front light on the power switch blinks also along with the status light on the mobo.

Anyone have this issue before?

[14049752]

I'm about 99% sure that this was a known issue with these a few years ago. I think there were a BUNCH of them that had that problem right out of the box, too.
It was the power supply on those system.

[anonymous Mac Tech]

You have to reset the PMU button on the logic board with the power unplugged. Give that a shot and see what happens.

[nj_computer_repair]

"Unlike models of Power Mac G5 or Power Mac G4 computer, the Mac Pro computer does not have a PMU. This functionality has been replaced by the SMC."

http://support.apple.com/kb/HT1806?viewlocale=en_US

I tried to reset the SMC with the computer off to no avail.

One thing that was interesting: I unplugged the connector from the power supply that connects to the system board right by the SMC switch. The computer obviously did not respond to the power button on the front but there was no clicking noise when I plugged in the power cord. The lights on the logic board were on and not blinking.

The power supplies for this computer are not cheap so it might not be worth repairing this system.

[anonymous Mac Tech]

Originally Posted by nj_computer_repair

"Unlike models of Power Mac G5 or Power Mac G4 computer, the Mac Pro computer does not have a PMU. This functionality has been replaced by the SMC."

http://support.apple.com/kb/HT1806?viewlocale=en_US

You said Mac Pro G5 in the thread title for which there is no such thing. I just went along like you meant a Power Mac G5 since you said its a dual 2.0 Ghz. Is it an Intel Mac Pro or Power Mac G5?

Some of the G5 towers had a button at the top right corner of the board for bypassing the power switch to rule out a faulty power button. You also might want to try reseating the processors. Then try removing the bottom processor and then try the bottom processor in the top spot because a bad/not correctly seated processor will show the same symptoms. Was the power LED flashing like no RAM was installed or flashing as the power supply clicked?

If its a Mac Pro check the video card for popped caps. Those things are famous for faulty video cards.

[nj_computer_repair]

My b! It's a Mac Pro INTEL - sorry about that. I will try what you suggested and post back. Thanks for the tips!

[14049752]

Yeah, I was going on it being a Dual G5 as well.... strike what I said.

You non-mac guys really gotta learn that not everything's a G5.

[nj_computer_repair]

I am slightly embarrassed right now - in any case, the project is being scrapped. Thanks for the tips anyway guys. Next time I will proof read before asking for help.

[14049752]

I am slightly embarrassed right now

Don't be! It's honestly an easy mistake to make..... It's just that it makes a ton of difference in terms of an answer. Tons of people call their new iMacs "G5" when I talk to them, so I automatically start remembering back to the failing logic boards and power supplies that plagued those system....only to find out that it's a new intel.

[nj_computer_repair]

Just embarrassed because I've been fixing Macs for a while. I love Mac naming conventions. It's been a long day, time to unplug and have some scotch