Previous 1 2 Next 25 Replies Latest reply: Oct 20, 2007 6:42 AM by stuartfletcheruk
hdlee Level 1 Level 1 (0 points)

Recentrly I purchased refurbished Mac Pro from Apple online store.
I have used it for 4 days so far, and found a serious power problem.
My Mac is shuting down randomly after using 2-3 hours.

The symptoms after shut down are as follows.

1. Power LED is still on after shut down, but whole system is not working.
No display, mouse & keyboard is not working, power supply is down...

2. I took a look inside Mac after shut down and found two red diag LED is on.
It was PUA and PUB.

I tried to reset SMC module but it doesn't fix the problem.
It looks obvious that power supply or SMC module has a problem.

Did anyone here have similar problem like this?


MacPro1.1   Mac OS X (10.4.8)  

MacPro1.1, Mac OS X (10.4.8)
  • Photogenic Level 1 Level 1 (0 points)
    I am having this problem as well, and found it just started happening after I downloaded the firmware update. I am also running Parallels, but I think it happens when it is both on and off, so I don't think that's the problem.

    I also tried resetting the SMC.

    HELP! Thanks, Caitlin

    Mac Pro   Mac OS X (10.4.8)  
  • Photogenic Level 1 Level 1 (0 points)
    I did an AHT (hardware test), which you might try as well, but everything checked out OK for me. You have to insert your Mac OSX Install Disk 1, reboot while holding down the D key.
  • Tesselator Level 1 Level 1 (70 points)
    I have no idea if this has anything to do with it or not but
    MacPro fans don't seem to kick in (ever!) and the CPUs, and
    drives are running at over safe limits in some people's MacPro's.

    The proc (and maybe the OS??) have shutdown failsafe mechanisms
    built it. This might be the cause. Get a monitor and see if
    your temp is ~65 or lower. If it is then it's a different

    There's a recent thread somewhere that tell how to kick up
    the fan rates to avoid this trouble. Might wanna search
    for that.

    Good luck!
  • Danzino Level 1 Level 1 (0 points)
    I'm having the same issue too. My Mac reboots without warning completely randomly. Sometimes it can stay up for days and work quite hard compiling, encoding, running a Parallels VM etc before rebooting. Other times it will only stay up for a few hours and only be doing something simple like playing a DVD or some music in iTunes before it reboots.

    It's as if someone has come along and pulled the power cable out of the back and then plugged it back in straight away. Sometimes it will power back on for about a second and then reboot again repeatedly 3 or 4 times before making it back into the OS.

    I have tried numerous PRAM and SMC resets but they don't appear to have helped. The OS and firmware are all fully up to date. The console logs have no information that relates to the crashing and TechTool Deluxe's simple tests report everything to be fine.

    I don't think it is an overheating issue as the fans kick in if I am doing a heavyweight Shake job and it hasn't crashed whilst doing that.

    It's becoming extrememly frustrating. If anyone can shed any light on this I would be most grateful. I don't really want to send it back as I need the machine to work, but if it keep happening it may well have to go. I suspect the tech guys at Apple will have a hard time tracking this down as I can't seem to make it happen on demand, and it can be days between failures.



    Mac Pro 2.66GHz 2GB ATI X1900   Mac OS X (10.4.8)   Second Seagate SATA 250GB Disk added after purchase
  • The hatter Level 9 Level 9 (60,580 points)

    I assume you have a UPS that can handle the load, and that you aren't overloading the circuit breaker... I'm surprised there isn't something somewhere, panic.log, how about ipfw logging? (I don't know why or where, but I have set my router and firewall to alert on ARD port (Apple Remote Desktop, which I don't own or have installed) service attempts and it seems like someone out there is trying to access the system).
  • Danzino Level 1 Level 1 (0 points)

    I am not running with a UPS, my Mac Pro is plugged into an 8 way surge protector along with the display and a few low power peripherals like a wireless mouse and a DECT phone. The other devices on the board don't reboot or anything like that so I don't think it's the power supply to the machine from the wall.

    I don't have circuit breakers on the fuse box in my house, it's old fashioned fuse wire.

    There isn't anything in ipfw.log, indeed I'm not sure why IP forwarding/firewalling would cause this? Panic.log has some entries but nothing marked with the time of the reboots.

    Thanks for your reply.


  • The hatter Level 9 Level 9 (60,580 points)
    I mention the firewall and ARD only to bring attention to the number of remote attempts. Nothing about IP forwarding. Only that it is nice to turn on ipfw logging under advanced section.

    There shouldn't be a panic.log unless there have been ECC errors or something else.

    The MacPro has a large "pull" of current on startup and wake from sleep that has plagued some users, either the UPS didn't provide enough for those in-rushes, or old house current. I would not run a Mac Pro w/o a 1000VA UPS though. It might just help with this and power fluctuations.
  • Danzino Level 1 Level 1 (0 points)
    Hi Hatter,

    Thanks for the prompt reply. I am behind another firewall which doesn't forward anything onto the Mac Pro, only my Mac Mini server so it shouldn't be seeing anything spurious on the ethernet, but I have enabled logging just to check.

    I shall invest in a 1000VA UPS and see if that helps. Although, it would be nice if the machine weren't quite so sensitive and required me to spend more cash to ensure it doesn't fall over, if indeed that is the issue... Such complex machines can be so hard to diagnose sometimes.


  • The hatter Level 9 Level 9 (60,580 points)
    You could log your mini's firewall as well, just to see. I have two routers and each has different set of firewall rules. One of the things I had to do was add filters and rules for ALL outbound services traffic. (I also installed Little Snitch, which was a real eye-opener about who/what I am connected to at odd times).

    I mention the 1000VA as that would be the minimum and should prove enough, and should provide even steady current, no dips or spikes and keep your system up and running. I have modem, router etc on its own as well. The power out here is such that you can't rely on it 100%... some weeks it is fine, and sometimes there are multiple 3 second outages... and storms.

    If you look for "UPS" threads, you will find some other user stories.
  • Ronald Altmann Level 1 Level 1 (5 points)

    I know, this thread is not new, but it describes best the problems we are also experiencing with one of our customers' Mac Pro 2,66 GHz. The symptoms described here perfectly match, maybe I can summarize the whole phenomenon as far as we have been testing it:

    - The computer randomly shuts down independently from CPU load or operating system (we also experienced shutdowns when booting from an Apple Mac OS X install DVD, as well as when displaying the login window after a cold start or after 2 hours of work).

    - After the computer shut down with a click, the power LED on the front panel stays on and the CPUA and CPUB OVERTEMP LEDs on the diagnostic section of the mainboard also turn red.

    - The problem seems to be independent from CPU loads as we have been using Marcel Bresink's SystemLoad and TemperatureMonitor utilities and even when exposing the system to 100% load on all CPUs we could not provoke a shutdown. Indeed, the fans of the Mac Pro really seldomly spin up ...

    What I am interested in: Does any of you have a solution in the meantime? Was your hardware exchanged and - if so - is the problem solved now? Did you try using the computer on another plug or AC circuit? Currently, we are testing the respective Mac Pro in our rooms and for the last 48 hours it did not shut down.

    Thank you for all of your feedback!

    PowerMac G5 Quad 2,5 GHz, MacBook Pro 17", Mac mini Intel, and more...   Mac OS X (10.4.8)  
  • Michaelworks Level 3 Level 3 (695 points)
    When you transferred the Mac Pro to your location, you probably reset the SMC. If you don't experience any issues as far as overheating, take it back to your customers location, test the wiring with a cheap tester for correct grounding etc. and measure the voltage to be sure it isn't close to brown-out levels. Just my thoughts on it.

  • Ronald Altmann Level 1 Level 1 (5 points)
    Hi Michael!

    Thank you for your response! Regarding the SMC I forgot to add before that we already reset the SMC very often on the customer's location; Either by deconnecting the Mac Pro for 30 seconds up to hours or by pressing the SMC RESET button on the mainboard with power connected. In most cases the Mac Pro did not start up again after a random shutdown if the SMC was not reset before.

    If we still have no "luck" in provoking a random shutdown here, we will test the power outlets as you suggested.

    Anyway, any experiences of affected Mac Pro users of this forum still are welcome!

  • Michaelworks Level 3 Level 3 (695 points)
    The SMC board controls all power functions, including fans. The fact that the overheat LEDs were lit, makes me want to say have the SMC and the main board checked by Apple. The shutdown with only a click makes me think of shutdown due to heat, and then having to SMC reset before it will boot again. Was the unit placed where anything could block free air flow, or is the ambient temp at that location different than where you have it now? I would lay out a Matrix between the two locations, and see what is different. It may be very simple...... or really tough to find :>( Good luck.

  • Dan Alderman Level 1 Level 1 (0 points)
    Hi there,

    I am also experiencing exactly the same issue. It used to be quite frequent, but it hasn't happened now for about two weeks. It seems to be utterly random. Large or small load, cool or hot, long or short uptime... doesn't seem to make a difference.

    I have the 2.66 model with 4GB RAM (all Apple original in 512's), ATI 1900XT, a WD 500 in bay 1 (Tiger), 2 WD 250's (Striped homes) in bays 2 and 3, and a Seagate 250 for other OS's (Vista Ultimate 64 and Ubuntu Edgy).

    I have put the config back to how it came out of the box, re-installed the OS, reset the SMC and PRAM many times, but that has made no difference, it still happens occasionally in either configuration.

    I have also experienced the same problem when using Linux booted in native mode. A click and then it reboots as if someone pulled the power. As it happened whilst booted in a different OS I am now assuming this is a firmware/hardware failure of some description somewhere along the line. As other users sometimes there are 2 or 3 reboots before it makes it back into the OS.

    I have run all kinds of diagnostics programs and they all report no issues with anything. The only other problem I have observed is display corruption when using Aperture, but I have put this down to poor GPU usage, or maybe not...

    My machine and display (20" ACD) are plugged in to a Belkin 1500VA UPS.

    The UPS never complains about the power coming in and doesn't appear to have anything to do with these resets. It's stable and never complains.

    I believe there is a faulty component in the Mac Pro power supply that is causing this, but I do not have enough knowledge or equipment to prove this. I have also suspected the graphics card on occasion but again, I have no evidence. I have spoken to Apple support about this, but even with the £200 Apple Care they said I would be without the machine for up to 2 weeks which is unacceptable to me as I need it to earn a living.

    I have been living with the random reboots for now, but it has lost me several hours of work before now so it's becoming extremely disappointing and frustrating, especially having now spent in excess of £2500 on this machine. I expect better from Apple for the money.

    I am about to spend a large amount of cash buying several new multicore intel workstations for my place of work. I am currently put right off the Mac Pro because of this unresolved issue, which is a shame. It's currently the only machine which will support all the OS's we need to use (Tiger, Vista and Ubuntu).

    Any info on this would be greatly appreciated.

    Kind regards,

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