The Mac Pro First Generation is an Intel Xeon-based workstation computer manufactured by Apple Inc. The first generation model includes the machines from 2006 through 2008.

278 Questions View all

Is my power supply failing?

I have a Mac Pro 3,1 2008. The machine start up automatically when I connect the power cable to the socket. I did not even press the power button.

Also, when I shut down the machine, the light on top of the power button is still on indicating the machine is still operating but in fact it is shut down.

What is wrong with the machine? Is this the signs of power supply failing or other problems?

Answered! View the answer I have this problem too

Is this a good question?

Score 0
Add a comment

1 Answer

Chosen Solution

Your system has a soft power on/off system which clearly is failing.

Lets try this first open your system up to locate the front panel board (what the front ports are mounted to). The power button is wired to it. Disconnect the button and see if the system still reacts the same. If it reacts differently then you know the button its self is bad.

Carefully remove the rubber cap over the LED. Then carefully pry up the C ring to pop the button out. If you find the button is gummed up try cleaning with a good quality Isopropyl alcohol (85% or better). Using an Ohm/continuity meter you can test out the button.

If it reacts the same way we'll need to do some more digging.

Was this answer helpful?

Score 2


Hi thanks for your help. However I tried your method and the computer still started up when connected to a power cable.

Apparently it is not the button problem.


Doesn't sound good ;-{ Sadly you likely have a power supply issue. Depending on the unit you may have a stuck relay and/or the switching FET transistors are blown within the power supply. At this point you may find it easier to just replace the full assembly.


Add a comment

Add your answer

Jack Lee will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 1

Past 30 Days: 1

All Time: 300