Defective power supply?

Discussion in 'Mac Pro' started by Infrared, Mar 2, 2008.

  1. Infrared macrumors 68000


    Mar 28, 2007
    These power supply temperature were taken while idling:

    [Mac Pro A]

    Power supply 1: 63C/145F
    Power supply 2: 72C/162F

    Would you say those temperatures are a little bit high?

    Temperatures taken from another Mac Pro under similar

    [Mac Pro B]

    Power supply 1: 31C/88F
    Power supply 2: 37C/99F

  2. mrcandy macrumors regular

    Nov 12, 2007
    Calgary, AB Canada

    My power supply temps are at 50C and 55C with an ambient reported as 26C. I have five internal drives plus optical, 10GB RAM, and a 2600XT plus 8800GT installed in the MP.

    Your temps look high, might be a fan problem rather than PSU? My PSU fan is at 640 rpm. Have you tried smcFanControl to crank up the PSU fan? You should be able to hear it at 100% which would confirm if it's working or not, and the PSU temps should drop if it is.
  3. Infrared thread starter macrumors 68000


    Mar 28, 2007
    Thank you for your reply. iStat Pro reports that the PSU fan is
    running at the expected 599 RPM.
  4. GregPacker macrumors member


    Jun 27, 2007
    Wherever there is a queue
    I had the exact same issue with my first mac pro 2008. PSU temps were 65 and 75 celsius, everything else was normal. I took it back to the Apple store and exchanged it. The replacement had normal PSU temps, but unfortunately also had the ATI 2600xt graphics freeze issue. Returned that for a refund and now waiting for one with an 8800 to ship. I dread to think what will be faulty with this one.
  5. Infrared thread starter macrumors 68000


    Mar 28, 2007
    Thank you for your reply. Tragically, this machine is itself
    a replacement for a broken MP. I too am dreading what will
    happen if I exchange this one :)

    By the way, did your first MP 2008 make any sort of clicking
    noise when connecting to a live power source? My first one
    didn't, but this one with the strange PSU readings does.

    I spoke to Apple and, while they were generally friendly and
    helpful, they were of the opinion that there is no fault unless
    the machine's thermal shutdown mechanism is invoked. I really
    cannot accept that. These readings, if reliable, are really not
    normal for a properly functioning computer power supply.

    Here's a comparison between the old and new machines:

    temperature comparison.png

    Some variability I would expect. But a 30C+ increase is rather
    dramatic :)
  6. GregPacker macrumors member


    Jun 27, 2007
    Wherever there is a queue
    I didn't notice any clicking noise on mine.
    If you can reach an Apple store then take the faulty mac pro there and show them how your PSU temps are double what the demo mac pro in the store has. You can also show them various threads at macrumors where people have posted screenshots of their normal istatpro readings. With no extra hard drives or other stuff plugged in there is no way the PSU should be so hot - imagine how hot it would be with 4 1TB drives, 4 pci cards, firewire devices, usb devices, 8 RAM DIMMS etc.
    My guess is that either the temperature sensors are giving faulty readings, or the PSU airflow is not right, or it was badly put together and something is not properly coupled to its heatsink. If you have had it less than 14 days then I think they have to let you return it. If they say it's not faulty and won't let you exchange it then just ask for a refund, then buy another one. Better luck next time!
  7. Infrared thread starter macrumors 68000


    Mar 28, 2007
    I've sent some links and a comparison screenshot of the current and
    previous MP readings. Alas, in an Apple email:

    "As Apple does not recognized any application to measure the temperature
    I cannot say if this is normal or not."

    I wouldn't expect Apple to accept the readings taken by any old 3rd
    party app. One hopes they have some means of reading the thermal
    sensor values to see if they are sensible. A faulty sensor is in itself
    bad news.

    Because they draw more power or because they create a warmer
    environment in which it is harder for the power supply to be kept

    Curiously, the temperatures seem to be lower under load then when
    idling . I can't say if that's normal behaviour. When I'm doing some
    relatively intensive stuff, the power supply 2 reading can go as low
    as 58C. Not particularly low, but a lot better than 70C!

    Sounds reasonable.

    I'm not sure where I stand here. The original machine was collected in
    early January. Apple said it needed repairing, so I asked for an exchange
    which they granted. The new machine has been here for 3 days or so.
    Does the 14 day period apply to when the new machine or the replacement
    was collected? I would guess when the original machine was collected,
    though they did give me a new receipt.

    It's a pity this has dragged on so long, but I didn't realize initially there
    was a problem with machine number one.

  8. Infrared thread starter macrumors 68000


    Mar 28, 2007

    Apple have agreed to exchange the machine for a new one.

    That's good news. But...well... I've been agonizing over this.
    Apart from the higher-than-normal PSU temperature readings,
    everything about this machine seems perfect. So I'd rather
    not swap it. But I also know that a faulty power supply can
    be extremely bad news. People have had their logic boards
    destroyed by exploding power supplies in the past. That may
    not happen in my case, of course, but lacking a reason why
    my PSU has atypical temperature readings, I'm inclined to
    fear the worst. So I guess I will reluctantly swap the machine.

    I wish Apple would produce a more consistent product. What
    with this, the HD2600 issue, the rebooting issue, the fact that
    you don't know which hard drive will come with the machine,
    it all feels like a bit of a gamble. If you win, that's great. You
    get one of the finest desktop machines ever made. If not, well,
    at least you get another chance to win.
  9. dchao macrumors 6502a

    May 20, 2008
    I just got my Mac Pro. And I've got the same readings as you have there from MacPro-A. I put my hand over the back PSU exhaust, and there is no way that the internal is as high as 60-70C. Also I let the Mac Pro rest for 30 min and then take the readings as soon as Mac OS boots up, and the readings start out at around 50's.

    If fact, you can not even change the fan speed from SMC fan control. In most PSU's, they have their own internal microprocessor logic boards to regulate the temperature without the help from the motherboard CPU's (in case the mobo CPU is in sleep mode).

    Also, under heavier CPU load, the PSU temperature should not have dropped without an increase in fan speed, it's just not logical.

    My conclusion is that we must have a different revision of the PSU, and there is a bug in iState that's causing the incorrect temperature display. For now I just subtract 30C from the iState's values for PSU to get the rough estimate. And I don't think our brand new PSU is faulty either.
  10. Infrared thread starter macrumors 68000


    Mar 28, 2007
    Thanks for that. Yes, I was thinking along similar lines myself. It was
    the temperature just after startup that made me question iStat Pro.

    In the end Apple were nice enough to replace the machine. And I took
    that option because Apple couldn't supply a reasonable explanation for
    the temperature differences.
  11. jjahshik32 macrumors 603

    Sep 4, 2006
    So does your 3rd (new mac pro) have lower psu temperature readings?
  12. bird2jet macrumors newbie

    Jul 24, 2008
    Hey Infrared,

    I think your having a different problem then jjahshik32 and myself. My PS1 reading is always HIGHER than 2, not the other way around. At least according to iStatpro.
  13. Infrared thread starter macrumors 68000


    Mar 28, 2007
    Yes. Currently:

    PS1: 33C
    PS2: 39C
    Ambient: 27C
  14. Infrared thread starter macrumors 68000


    Mar 28, 2007
    It's certainly possible I had a different problem to yours.

    Then again, if the readings are not trustworthy, you could
    be getting any sort of random nonsense as readings.

    Note: I also mentioned the clicking noise.

    Thanks for your replay, bird2jet. I hope you resolve this.
  15. jjahshik32 macrumors 603

    Sep 4, 2006
    Is there a way to find out what type of psu that apple has been using?

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