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Mac Pro 2008 3,1 Constantly rebooting

H

howzitjoe

macrumors newbie
Original poster
Jan 22, 2008
16
0
The Island of Hawai'i
Aloha,

I bought a used Mac Pro 2008 3,1 on ebay (I'm foolish) seller said it needed a video card and memory but was in good working condition and had been checked by a company called MicroCenter. I installed NEMIX ram and an nVidia Geforce 6800gt video card. Installed Snow Leopard then upgraded to Mavericks.It worked just great for about 3 days then it begin rebooting constantly. It wouldn't boot into the Snow Leopard disc either. It would get to the Apple symbol then reboot. If I held down the S key at reboot it would grind away longer but still reboot. I removed drives, memory, video card, etc and reinstalled, cleared PRAM, SMC etc. After rebooting for a while in safe mode it finally loaded the Snow Leopard disc and I did a complete reinstall on a brand new WD 1T drive. I checked the LED troubleshoot lights for the powersupply...yellow and green. Worked for about 2 days then begin the constant reboot again. Played around with ram, drives, etc but still a no go. I did not have a disc with AHT but finally found copies at https://github.com/upekkha/AppleHardwareTest and got the 3 listed for my version 2008 3,1. One of them worked and I was able to run AHT...no errors on the short test but the detailed test stalled after running overnight. BUT now when I rebooted it actually booted into the WD drive just fine. I'm running TechTool Pro 7 on it now to see if it can detect any problems.

Anyone have any suggestions about what has been causing the issue? I still don't trust the system and would like to figure out what might be the problem.

Mahalo,

Joe
 
You need to bake it. Google "Bake MacBook Pro" -- some disassembly required. The entire process should take 2 hours.
 
dude. you should have immediately returned it to the seller.

Ebay buyer protection is so biased towards buyers, its ridiculous.
 
mac Pro not macbook pro

Djfremen said:
You need to bake it. Google "Bake MacBook Pro" -- some disassembly required. The entire process should take 2 hours.
Click to expand...

Thanks but it's a mac pro desktop not laptop.

----------
Korican100 said:
dude. you should have immediately returned it to the seller.

Ebay buyer protection is so biased towards buyers, its ridiculous.
Click to expand...

I'm naïve and believe that the seller wasn't tech savvy and did have it checked

----------
CanadaRAM said:
Random rebooting usual suspects (keeping in mind that it may be more than one thing):

Heat issues
Flakey Power supply
RAM or memory riser board failure
Motherboard issue

PS: Will be in Kona in a couple of weeks for holiday.
Click to expand...

Yeah I thought about the PS but it seems to check...even plugged it into a wall socket and changed the power cord to see if that might have been it.
I've switched around the riser boards and modules...sticking with one riser with all 4 modules on it. I used Tech Tool Pro 7 and everything passed.
I hope it isn't the logic board but that's the usual default when the Mac Geniuses can't fix something. I've read though that that is sometimes not the solution.

Running a temperature monitor on it now and keeping the side of the case off just to see if it's an overheating problem.


You'll have a great time here...bring sunscreen.
 
One bad memory module

Update: one of the red lights starting staying lit on the riser board so it looks like I have one bad Nemix module. It passed the memory test of AHT and MacTools which is kinda weird. I ran full test on all 4 modules and found that 3 of them have Micron chips and one is a Samsung. The Samsung and one of the Micron chips run hotter than the other 2 chips (including the bad one.) Returning the Samsung chip and the bad Micron chip so at least I'll be left with 2 Micron chips even though one of them runs hotter than the other by about 5 degrees C. All and all the chips are Nemix.
 
So far so good

It's been running fine for a week after I removed the bad memory, I've been using smcfan to keep the fans running a little higher and the side cover is off. Ambient temp here is 75-81 Fahrenheit. Memory chips stay under 140 and only the northbridge is running a little warm at 153. Only weird thing I've done is have the video card in #1 slot but the extra power connector plugged in the wrong MB socket. But it works. Using Orcacle VM to run Windows 7 too.
 
Mac Pro 3,1 Randomly Rebooting

Hey guys,

Mine is constantly randomly rebooting as well.

CanadaRAM said:
Random rebooting usual suspects (keeping in mind that it may be more than one thing):

Heat issues
Flakey Power supply
RAM or memory riser board failure
Motherboard issue
Click to expand...

Is there any way of narrowing down which it could be?


As for what I can do about each...

Heat Issues
It's quite dusty in there, I might give it a clean out...

Flakey Power Supply
Is it possible to get this replaced?

RAM or memory riser board failure
Can buy new RAM, but second hand risers don't seem a good option

Motherboard Issue
end game?


EDIT:

Did a RAM test

Coincedently decided to get iStat last night. Just installed it and it was reading 4GB! (when I have 10GB worth in there). Did some location tests to see if I could find anything culprit.

Test 1

Top
Riser A
2GB
2GB
1GB
1GB
Bottom
Riser B
2GB
2GB
-
-

Reading 4GB


Test 2

Top
Riser B
2GB
2GB
1GB
1GB
Bottom
Riser A
2GB
2GB
-
-

Reading 8GB


Test 3

Top
Riser A
2GB
2GB
-
-
Bottom
Riser B
2GB
2GB
1GB
1GB

Reading 4GB


Test 4

Top
Riser A
2GB
2GB
-
-
Bottom
Riser B
1GB
1GB
2GB
2GB

Reading 6GB


Test 5

Top
Riser B
1GB
1GB
2GB
2GB
Bottom
Riser A
2GB
2GB
-
-

Reading 10GB ?!


So now it's reading the full 10GB. I'll keep an eye out for random reboots or a drop in read memory.
 
Last edited:
Strip it down and thoroughly clean it, riser cards, can of compressed air, denatured isopropyl and my trusty dyson hand held.

The PSU needs a bit more power than a can of air, I take mine to a workshop and use an air line in short sharp bursts baffled with what we call a tea towel over here in the UK. But I wouldn't think that would be the problem.

Off topic slightly I now have memories of just how much gunk came out of a PowerMac's PSU from an air line blast :D
 
Recently replaced the DVD-R in my 3,1. In the process I got a considerable amount of gunk off the front fans and the GFX card. They do suck lots of detritus over time. All my temps dropped by about 10ºc.
 
In my many years of desktop support, I've found a good run through with an air compressor at low power does wonders. I blow out my 3,1 and 1,1 twice a year.
 
Back to square one

well it's doing it again. After a week of zero problems. I had gotten some me additional ram via Amazon. Installed it but it was reading incorrectly 2G chips instead of 4G chips. Amazon is sending replacements. So anyway I was a TechTool Pro 7 complete test which was at the time scanning one of the drives for bad sectors when it began rebooting again. It is very hot and humid here today. 86 F

So I took everything out including the PS, DVD, riser boards, memory, video and blew everything out. Tried leaving out the DVD just in case, but no go. I'm thinking either the PS overheats (fans are running ok) or it might still be funky memory or riser boards. Of course the end game would be the logic board. When it was running the temperature on the Northbridge was a constant 63 C which was the only unusual temp I could see. The Northbridge Chip itself was running 43 C.

I'm gonna let it sit until the air temp gets cooler and/or wait till the new memory gets here. Any suggestions on what to replace next?

Thanks, joe
 
Last edited:
Power supply is pretty easy to replace if you're good at reading directions.
Did it on my 3,1 and it fixed the rebooting problem.
Not sure if this is what your problem is, but it might be.
 
Cooler

OS6-OSX said:
How many PCIe slots are available? Try a PCIe slotted fan to help circulate more air http://www.vantecusa.com/en/product/pro_list/37
Click to expand...

That is a thought. I am keeping the side panel off since the initial problem.

Thanks,

Joe

----------
Mactrunk said:
Power supply is pretty easy to replace if you're good at reading directions.
Did it on my 3,1 and it fixed the rebooting problem.
Not sure if this is what your problem is, but it might be.
Click to expand...

Yep, not too hard...I took the thing apart today just to get the model number off the PS.

THANKS,

Joe
 
Error code 4SNS/1/40000001:VMAS-0.000

i got it to boot into AHT and ran a deep scan. This is the first time it returned an error code indicating a failed sensor. This would make sense of its a heat sensor on the logic board. Unfortunately everything I've read gives no clear interpretation of the error code. Everything from bad video card to bad logic board. I switched and swapped the riser boards and memory chips to see if I could isolate one component and run the AHT test. Still couldn't nail it done to one piece of hardware. In any case it begin booting into the Mavericks system again perfectly. I ran a Disk utility file permissions repair and checked a few other things. Does anyone know of any software utilities that can check hardware besides AHT and Tools?

Thanks,

Joe
 
howzitjoe said:
i got it to boot into AHT and ran a deep scan. This is the first time it returned an error code indicating a failed sensor. This would make sense of its a heat sensor on the logic board. Unfortunately everything I've read gives no clear interpretation of the error code.
Click to expand...

VMAS stands for "Voltage Memory riser A Sensor". It seems to read 0.000 V
 
OS6-OSX said:
Here is a site where you can check parts and part numbers. Their prices are kinda high so it may be the only use for the site
http://www.macpartsonline.com/mac-pro-parts.html
Click to expand...

Thanks, that's a great site for research!

----------
666sheep said:
VMAS stands for "Voltage Memory riser A Sensor". It seems to read 0.000 V
Click to expand...

Hmm...so that could mean its getting a bad voltage reading from the chips. They are after-market chips from NEMIX.

Thanks,

Joe

----------

Okay, the latest. After running the AHT a few times it booted up perfectly. I played with the fans speeds but decided to leave them at an acceptable noise threshold and leave the computer running.

I put the side of the case back on after reading that the design of the closed case makes it important for the cooling.

I further investigated the proper placement of the memory chips (which I had placed on the same riser board) and split them between riser board A and B.

I installed iStat and the riser board voltages are A: 11.86 B:11.93.

Lets see how long it will run before it repeats the problem. So far it's been up 1 day.

Joe
 
More memory added

The computer ran for 3 days without a burp. Ran photoshop, iTunes, Office etc to put some load on. I finally got 2 replacement memory modules from Mac Ram Direct via Amazon so I shut down and installed them. Configuration based on the official Apple service guide was matched pairs on risers in slot 1 and 2. Restarted without an issue and this time the ram showed as 4G per module. Up-time is now 13 hours so hopefully it will stay up. Using iStat and Temperature monitor to keep an eye on things. Northbridge Chip is the only thing constantly running hot at 63 degrees but the Northbridge Core is at 38 degree which seems kinda funny.

Thanks,

Joe
 
Knock on wood

Update...it's been running continuously for a week with no issues. I got brave and booted into AHT and did a quick test which it passed, then a deep test which it also passed. Hopefully it was just some bad memory that was causing problems, although I'm thinking that the TechTools Pro 7 deep test might have screwed things up whether with permissions or whatever. My temperature reading are the same with only the Northbridge chip reading high at 63 C.

I'll post any disasters otherwise if you have similar issues let me know.

Mahalo,

Joe
 
howzitjoe said:
Update...it's been running continuously for a week with no issues. I got brave and booted into AHT and did a quick test which it passed, then a deep test which it also passed. Hopefully it was just some bad memory that was causing problems, although I'm thinking that the TechTools Pro 7 deep test might have screwed things up whether with permissions or whatever. My temperature reading are the same with only the Northbridge chip reading high at 63 C.

I'll post any disasters otherwise if you have similar issues let me know.

Mahalo,

Joe
Click to expand...


Hi Joe:)
I seem to have run into a similar problem regarding the rebooting. Right now I am testing the RAM one block at a time, but I was wondering whether your Mac is still running smoothly or not?

Best

Frederik
 
I have inherited a customer's Mac Pro 3.1 that was rebooting, he has moved on to a new trash can mac pro. I have seen this before and the most likely suspect is a ram module or the riser card its on.

You need to try different combinations of these to isolate the problem to a particular simm or riser card. Unfortunately you will need to run it for a while until you are sure. In my case waking from sleep seemed to bring on a restart, and it seems to be a simm fault/mismatch. The lights on the riser card are not coming on to indicate an error.
 
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