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  • FunkyRico Level 1 Level 1

    Take a look at our problem in the thread below.. does it sound similar ?

    keep in touch,
  • Maro_jpn Level 1 Level 1
    My first problems was when I made Mac sleep, it shutdown without sleeping. I thought then it would be some system error so it would go away with upgrading to Snow Leapard(Leopard then). So I left it as it was. But then this immediate-shutdown-at-startup came about a month later.

    What I have done for the shutdown problem were SMC reset, cache cleaning and other well-known maintenance methods. But nothing worked. (I was able to startup from USB HDD I made for emergency.)
    Then I changed a little 2032 battery and upgraded to Snow Leopard(HDD repartitioned but used Carbon Copied previous system). It has been 2days past and shutdown-at-startup has NOT happened( yet sleep problem continues).
    Was it some kind of system error or a problem on HDD? It is OK now but I am afraid that the problem might occur again and PSU would be the reason. (I am not an expert and only judging from the articles on internet...)
  • Maro_jpn Level 1 Level 1
    Like I said my Mac Pro stopped booting again. This time it shuts down much quicker than before!
    I am going to try replacing PSU and see how it will be. I am getting it from the US so it will take for a while (I am in Japan). I will report about it when I get it.
    Thank you. -writing from borrowed MacBook-
  • The hatter Level 9 Level 9
    Wonder if maybe you don't also need a UPS to protect and give the PSU better line current as well as the normal brownout, outages and spikes or uneven current.

    Did you ever get out your OEM DVD and run Apple Hardware Test?
    Test RAM? printers and USB cables and drivers (and others)?
    Clean install on stripped down hardware too.
  • Mike Vigil Level 1 Level 1
    I have a similar problem.....

    Before just tossing parts at this machine...
    Mac Pro 8 core 3.0ghz ( A-1186 ) ...
    Did the pull the on board battery ( with AC off )
    This machine was STUFFED with dust bunnies and went through a full cleaning.
    Re gooped the CPU's ( Arctic silver ) and the machine is running cooler.
    ( based on hardware monitor )

    Using the motherboard test lights... I get a trickle fail..
    ( I assume that what a yellow light means there)
    The machine boots off the hard drive ( but not a boot disc )...
    I'll get all the way up and can start using the machine....
    and the EFI GO blinks off / the GPU light goes away.
    The machine shuts down & restarts right back up......

    Im stripped down to 2GB of memory ( 2 1GB sticks ) in the bottom..
    This cycle takes about 7 minutes when the machine is " cranky ".
    And it's random... last night I ran for 2 hrs with NO ISSUES...
    this am .. back to the 7 minute thing.

    So any thoughts you have would be great.....
    Happy New year~

  • Mike Vigil Level 1 Level 1
    Ok a little more research....
    And a question or three...

    1) Is the trickle light always amber? ( I assumed a bi or tri state led ) thinking green was the ticket.
    2) If you have the diag light switch pressed ( eg with a pencil between the aluminum frame of the dimm cards and the push button ) will that give you more info ( that you can see a CPU error or over CPU temp) or do you have to monitor these with the button not depressed ?
    3) Is the 5V rail more like 7.15 volts?

  • Mike Vigil Level 1 Level 1
    A little more info.....

    I played a demo for about 3 minutes Quake 4 to make the video work for it.. a little bit.
    Now here's what I've found...

    On restart..
    Trickle on..
    Power on..
    Then the EFI GD.. goes on & stays on
    Then the GPU light comes on..
    ( the gray Apple screen and the spinning gray " gear " icon )
    Get to blue screen
    Get to desktop
    GPU light blinks~
    EFI blinks~
    commence restart...

    SO without the video card... the unit boots.. and STAYS running with no issue..
    I do not have another video card to run with...


  • Maro_jpn Level 1 Level 1
    Early 2008 Mac Pro have had a lot of video card problems on Radeon 2600. I did have a bad card (lucky it happened during warranty so I got free replacement). It kept rebooting and killed HDD as well at the end so be careful!
  • Mike Vigil Level 1 Level 1
    This was a Aug 2006 build. Using a Radeon 1900..V 2.1 ( currently running 32 bit )
    I'm booting off a " disposable " drive...
    Trying to locate a video card to confirm my suspicions.
    I know there was a Radeon recall on the 1900 but mine isn't part of that serial number grouping.

    I spoke with Apple...
    The Yellow " trickle " light is it's only color.
    Everything is is pointing to the video card.. like when the machine is happy & I run Tech Tools
    and do a video mem test... it's instant reboot time.
    If I remove the video card.. I can put the machine in target mode and it runs forever.

    So I'm kinda stuck until I find a video card...

    Thanks for the reply

  • Maro_jpn Level 1 Level 1
    I got a PSU from the US for $140 including shipping to Japan. It took about a week to Japan.
    So far it is OK. It Boots fine and sleep problem is gone.
    I don't know if it the end of the trouble but it is working for now.

    Thanks everyone for suggestions.
  • Mike Vigil Level 1 Level 1
    Well in my case....
    The new video card , new memory & new risers ( DIMM boards ) didn't fix my issue.
    Looks like new motherboard for me.

  • kevvo_b Level 1 Level 1
    Hi Pete et al.

    I've been having this problem since August 2010. I posted here about it, and got nowhere really. I can say I'm having exactly the same issues that you had re powering up etc...and would be really interested in an update - i.e. has the PSU replacement sorted it out?

  • Colin Nobbs Level 1 Level 1
    I suspect this will be of no help to a lot of people but thought I'd post it just in case.

    My problem - macpro kept switching off and restarting for no reason. the fault got steadily worse.

    took in to my mac repair people. 1) they found one of the RAM cards was showing a fault (LED light was on to indicate a problem) and they simply reset it in place and the problem was solved. 2) They ran diagnostics continuously on it for 3 days (over new year hols) and it showed up a fault with the bluetooth card (registered as a fault over 100 times). They replaced the bluetooth card and so far - touch wood - no problems at all.
  • kyleung Level 1 Level 1
    I have been using Mac from the 6100/66AV generation for 7 years and then shift to PowerPC G4 867MHz for 7 years. The experience was indeed quite encouraging.

    My Mac Pro (Early 2008) suddenly shuts down in the last few weeks. I read all the replies in this column and so I bought my Mac Pro to the ASP. The technician confirmed that the PSU was fault and now replace with it a new part which cost me around US$250.

    I am quite sure that it should be a matter of quality. My display card in this Mac Pro was down in the last year and I replaced it with GT120, and now after two and a half year, the expensive PSU. I felt very disappointing that the highest end model did not accompany with a reasonable high standard of hardware quality.

    I will just buy the lowest end model in the coming years.
  • Mike Vigil Level 1 Level 1
    Well I got my new motherboard and it's back to 100%... no weird issues.
    Cost just short of 700.00 ( got a new motherboard from Apple thru We love Mac's ).

    Bolt in & go... the only thing I have to address is the boot up verbose dialouge on screen.

    So the moral of my story is clean your machine every 6 months....
    The PO on my machine left it filthy, and that caused thermal damage.