Mac Pro shuts off at start up, red light flashes once on motherboard

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Mac Pro shuts off at start up, red light flashes once on motherboard

Hello. My Mac Pro 3.2 ghz Quad Intel Xeon has recently started shutting off during start up. It has been spinning like a top for a year and a half, and then suddenly.... boom. It happened a few weeks ago for the first time. I just turned it off, as I didn't have time to deal with it that day. The next day I turned it on and it's been running like normal, until today...which was about 2 weeks of it working after the first shut down. When it does shut down a red light flashes briefly on the board behind the hard drive (which I believe is the motherboard?).

Any suggestions before I blow a bazillion dollars and or just buy a PC would be much appreciated. Thank you!

Mac Pro, OS X Mountain Lion (10.8.5)

Posted on May 12, 2014 3:05 PM

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Answer 1

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FatMac-MacPro

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May 13, 2014 8:34 AM in response to wedgie777

From the Technician's manual for what looks like a 5,1 Mac Pro:

"Note: When connecting the Mac Pro to AC power, verify that the LEDs for OVTMP CPUA and OVTMP CPUB briefly flash red (less than 0.5 sec). The LEDs are located under hard drive bay 1 on the backplane board. If they do not illuminate briefly, there is an issue with either the power supply or the backplane board. Generally speaking, power supplies can be affected by issues more than other modules. If you suspect a power supply has failed,verify it in another Mac Pro (Mid 2010), if available, before replacing any modules.

Note: The OVTMP CPUA and OVTMP CPUB LEDs on a properly functioning Mac Pro will also momentarily flash red immediately after the Mac Pro is disconnected from AC power."

That second note suggests either failure of the power source or you've got a problem with the power supply or, perhaps, the wiring connections.

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Answer 2

wedgie777 Author

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May 13, 2014 8:50 AM in response to FatMac-MacPro

Hmmm... is there any way that I can check that out? That sounds like something a professional should do, but I wonder.

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Answer 3

May 13, 2014 8:58 AM in response to wedgie777

The link I provided will get you to that manual, which has a bunch of diagnostic instructions. Check it out and see if it's worth a personal attempt. The easy part would be making sure your power source is totally reliable, from the wall socket to where the AC cord plugs into the Mac. And a UPS is always a good idea when you're not using a laptop.

BTW, was I correct about which Mac Pro you've got?

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Answer 4

wedgie777 Author

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May 13, 2014 9:07 AM in response to FatMac-MacPro

Well, I'm embarrassed to say that I don't know without looking. That seems right though. :/

Thank you. I'll take a look and see what I can figure out. I've done many a thing on several Mac's. Hopefully it wont be too daunting for me.

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Answer 5

wedgie777 Author

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May 14, 2014 6:39 PM in response to wedgie777

I was able to perform a basic hardware test, but not the extended one. My computer shut off during the extended test. But I came up with this error code.

4SNS/1/40000001:Ip6M-0.972

Seems to be some sort of logic board issue? Does that mean I just need to replace the whole thing? I keep reading stories of other getting this error code, taking it to Apple specialists, and they replace the video card.... and then they keep getting the same error code.

Still have yet to check the power supply. I'll do that tomorrow.

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Answer 6

May 14, 2014 7:03 PM in response to wedgie777

That is a sensor error. It says some sensor (probably a temperature sensor) is reading out of bounds or its wire is disconnected.

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Answer 7

wedgie777 Author

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May 14, 2014 7:12 PM in response to Grant Bennet-Alder

Any suggestions on what I should do about that?

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Answer 8

wedgie777 Author

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May 15, 2014 7:38 PM in response to wedgie777

Is there any way to tell for sure what kind of sensor needs tending to?... outside of an Apple store, that is.

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Answer 9

wedgie777 Author

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Jun 3, 2014 6:24 PM in response to wedgie777

Soooooo, went to the local Mac store (PeachMac), and they said my HD has a bad sector in it. I purchased a new HD, carbon copied all of my stuff over, and everything is fine. Or at least it was for a couple of weeks. I started messing around with some music (I make music on Pro Tools), and then... boom. My computer shut off and just keeps shutting off.

I've been told that this is a sensor error:

4SNS/1/40000001:Ip6M-0.972

But, can anyone tell me what sensor?!

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Answer 10

Mar 7, 2017 12:07 PM in response to wedgie777

Wedgie777, did you ever find the issue to your problem? Was it indeed the power supply or a sensor? I am having the same issues as you right now.

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Answer 11

Mar 7, 2017 12:13 PM in response to GANJAHONG

I know I am resurrecting a dead thread from years ago, but can't find answer for this anywhere. Sick of throwing parts at it and praying that one will eventually fix the issue.

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Answer 12

Mar 7, 2017 2:05 PM in response to GANJAHONG

do you have a wiggly northbridge chip? It is dead center of the processor board (on the slide-out shelf) on the 2009 to 2012 models.

http://www.xlr8yourmac.com/archives/jul14/071114.html

.

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Answer 13

Mar 7, 2017 5:26 PM in response to Grant Bennet-Alder

I have that chip, but did the hardware test and came up with no error codes. The retainer pin still looks good too.

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