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Mac Pro wont turn on...

A

Alaska_guy

macrumors regular
Original poster
Mar 30, 2018
137
12
Hard to diagnose since it's my wifes machine... The machines power led was blinking like it was in sleep mode. I could not get the keyboard or mouse to wake it. I went ahead and unplugged the power cord and now I can't get the machine to power on at all.

I tried removing all but 1 stick of ram etc. Doesn't seem to make a difference. When I plug the power cord in a red light towards the front of the case by the hard drive bay comes on for a split second and then goes away. I don't see any other power light indicators as if the motherboard is getting power...

Machine was working fine previously.

1ssd, 1tb spindle disk, r9280x video card and 48gb ram is the setup.

Any ideas? Any other way to boot the machine if the front panel button is the issue?
 
Try resetting the NVRAM three times? How old is the battery on the backplane? Lastly, check the northbridge heatsink rivets to see if they've popped. This could contribute to this....
 
Pulled video card, and tried to power on, same issue... No power at all. Unable to do NVRAM reset since its acting like no power is going to the board. No idea on the cmos battery age... I can take one out of another PC I have here and see if that helps. I pulled the heatsink, blew everything off and the rivets look fine. It's acting like a bad power supply.
 
Maybe the PSU is done.... What model Mac Pro is this? There are service manuals specific to each model that can help with reading the LED's you're seeing.
 
It's a 2009 Mac Pro. Only time the diagnostic light comes on is when I plug the power cable into the outlet. It blinks for a quick second. Other than that pushing the power button on the front of the case does nothing. The odd thing is the machine was acting like it was in sleep mode "slow power button blink" while it was plugged in. I simply powered the machine down to power it back up by unplugging the power cord because the keyboard and mouse wouldn't wake it and pushing or holding down the front power button on the case wouldn't do anything, now it won't do anything.

It's almost acting like the front panel power button isn't doing anything. You would think it would at least attempt to do something.
 
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Maybe leave it unplugged for 10 minutes and try again.... If the front panel is gone, not sure how you'd get it to boot by jumping the board. Someone else can probably offer some feedback.

Download the service manual in the link below and check the symptoms against it... I'm sure another forum wizard will have some suggestions as to what's causing the weirdness...

http://tim.id.au/laptops/apple/macpro/macpro_early2009.pdf

Sounds like a PSU issue to me....

See the top of page 105 in the PDF... Also, you can press the diagnostic button to see what led's light up.
 
Awesome, that helped. Pushed the diagnostic button on the mainboard and the SV_STBY illuminated yellow.
 
Did it boot? If the board and PSU are getting power correctly, it might be the front button panel.... That little manual is worth its weight in gold... Glad it's helping!
 
Jumpered the two pads as described on page 105. RED led lights on CPUA and CPUB. I only have a single cpu system.
 
Alaska_guy said:
Jumpered the two pads as described on page 105. RED led lights on CPUA and CPUB. I only have a single cpu system.
Click to expand...
Do you have another Mac Pro to test the PSU? It's the first thing that I do when a Mac Pro don't power on anymore.
 
Hmm, I think I might have touched the one right above the 2 pads your supposed to jumper. Every time I touch that pad it says OVTMP_CPUA and OVTMP_CPUB.

Weird considering it was working just fine a few weeks ago.
[doublepost=1559678039][/doublepost]Shrug, time to go back to a PC where its easier to fix/troubleshoot. Going to take the video card and drives out and use them in another build. Not worth my time to troubleshoot this old machine. No spare power supply/machine.
 
I have someone interested in purchasing it tomorrow for $250 with original video card, the 6 core processor and the 32gb ram. If they back out I will buy a used power supply for $65 and hope that's it.
 
Ok, he backed out... I went ahead and purchased a power supply off eBay hoping that does the trick. It will at least rule that component out. I bought the power supply instead of the logic board because a few months ago I was going around with one of those outlet power meters to see what was sucking up all the wattage in my house. When I plugged in the Mac Pro it would consume 125w when it was simply plugged in, not turn on, not in sleep mode! I was like woah... When turned on it consumed 300w! That seemed odd to me that it would consume 125w by simply being plugged into a wall outlet.

Will take at least a week before the power supply gets here, anything else I can do in the mean time to test the current power supply? Also, when they say logic board, does that refer to the board that the cpu and memory sit on?
 
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Alaska_guy said:
Also, when they say logic board, does that refer to the board that the cpu and memory sit on?
Click to expand...
What is the main logic board for other Macs, is the backplane with MP41/5,1. The board with CPUs and DIMMs is the CPU tray.
 
Ok weird, pulled the power supply out, blew it out with air pulled some screws off to inspect it, put it all back together as I didn't see any bulging caps etc... Put the power supply back in the machine and when I plugged the Mac back into the wall it booted up!?!!!

Going to put the drives and stuff back in and see if I can get it to stay on.
 
Alaska_guy said:
Ok weird, pulled the power supply out, blew it out with air pulled some screws off to inspect it, put it all back together as I didn't see any bulging caps etc... Put the power supply back in the machine and when I plugged the Mac back into the wall it booted up!?!!!

Going to put the drives and stuff back in and see if I can get it to stay on.
Click to expand...
When the PSU is failing, if you keep it disconnected for a long time (1h/2h) it sometimes works again. What just happened to you happened to other people here.

A new PSU will probably get you working again.
 
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Weird, yeah its working perfectly fine now... Wonder if there is some thermal protection in the power supply if there is too much dust?
 
Alaska_guy said:
Weird, yeah its working perfectly fine now... Wonder if there is some thermal protection in the power supply if there is too much dust?
Click to expand...
It's a 10 year old PSU, capacitors are already dry. ACBel made PSUs usually fail earlier than Delta, btw.

You have problems since the stand-by power usage is less than 10W.
 
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