Replaced Mac Pro PSU, now temperature running too high?

Discussion in 'Mac Pro' started by Rt&Dzine, Feb 7, 2010.

  1. Rt&Dzine macrumors 6502a

    Rt&Dzine

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    Oct 8, 2008
    #1
    Forked from here per request. --mkrishnan

    I just got a new power supply put in my 2008 Mac Pro Quad and the temps are running (with only Safari) (ambient 24°):

    Power supply 1: 65° C
    Power supply 2: 60° C

    Is this too high? My previous psu ran a lot cooler. The fan is currently running at 623rpm. Should I take it back to apple service?
     
  2. nanofrog macrumors G4

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    May 6, 2008
    #2
    What's the load on the PSU?

    If it's not at a full load (and you'd really benefit from a Kill-A-Watt), those temps are too high.

    You could also stick your hand on the back of the case where the PSU is, and see if the air's actually hot (it would be quite uncomfortable <hot water heaters are typically 55C, to give you an idea; 65C = 149F>, just in case the software's not reporting an accurate temp). An InfraRed (IR) Thermometer would help here, as it can give you an accurate temp.
     
  3. Rt&Dzine thread starter macrumors 6502a

    Rt&Dzine

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    #3
    Thanks for the response.

    The load can't be very much with only 1 processor, 2 hard drives, 8 GB RAM, and 1 graphics card.

    I felt more heat coming out from around the power cord plugin at the back of my computer than I remembered with the old psu. That's why I checked the power supply temps with iStat.

    I wouldn't say it feels hot. Just feels warm. But hotter than the air coming out of the exhaust fan at the bottom. The power supply fan is running a little higher at 620rpm.

    Where would I stick the IR Thermometer? (Obviously I'm not very technical.)
     
  4. Inconsequential macrumors 68000

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    Sep 12, 2007
    #4
    My 2009 Mac Pro (in sig) temp probes never really pass 40C, 45C under stupid loading everything to breaking point load.

    It's only a quad, but still even at idle its 35-40C max so something is wrong there!

    Edit: PSU sensors, obv.
     
  5. Rt&Dzine thread starter macrumors 6502a

    Rt&Dzine

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    #5
    Mine's only a quad too! :eek:

    PSU sensors? Do you mean that the power supply temp may be okay but the sensors are faulty?
     
  6. Inconsequential macrumors 68000

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    #6
    Well it could be mine aren't working properly, but after having three Mac Pro 2009s and the worst of them in the summer only hit 50C at the absolute maximum...

    I don't know where the sensors are located, it could be they are on the heatsinks for something and that the heatsink is loose.

    TBH if it dies, apple have to fix it.

    Don't worry about it to be honest, can phone them up and ask what they think but they will probably say its fine.
     
  7. nanofrog macrumors G4

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    #7
    I'm not suspecting it is. Maybe 300W.

    iSTAT could be reporting wrong, but with the description (namely the fan is ramping up), it seems to be real, not a software glitch or bad thermal data from the PSU.

    Take the side panel off, and read the metal case (give it time to stabilize first). You can compare that with the air temp as well. (IR's nice for that, as it's super quick).

    I'm getting the impression there's something wrong with this one as well. IIRC, Apple had gotten a hold of a bad batch or two, possibly from trying different suppliers (looking for cheaper, or their existing supplier had problems meeting the quantity demands).

    But 60 - 65C is to high for a PSU. I am presuming there's no dust blocking/hampering the intake fans (anywhere in the system).

    Rt&Dzine, if that's not the case, the whole system should be cleaned out with a can of compressed air (i.e. fans and heatsinks especially).
     
  8. Rt&Dzine thread starter macrumors 6502a

    Rt&Dzine

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    #8
    It was just cleaned out with air 2 weeks ago. I think it must be the new PSU which was put in yesterday. I'll have to bring it back in. :(

    Thanks a lot!
     
  9. nanofrog macrumors G4

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    #9
    :cool: NP. :)

    As it's currently working though, I'm not sure they'll do anything about it, and tell you "It's within limits". :rolleyes: I wish you luck with it. :)
     
  10. Rt&Dzine thread starter macrumors 6502a

    Rt&Dzine

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    #10
    I wonder if I'm doing something wrong. The metal case reads 32°C. If I shoot it from the back into the machine near the plug I get 42°C.

    ***

    I forgot to mention. This power supply also makes a loud click sound when I shut down. (Not to be confused with the quieter click sound when you remove the power plug.)
     
  11. nanofrog macrumors G4

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    #11
    No, it's harder to get a reading on the metal case at times (depends on the layout). Ideally, you'd want to get it off of the heatsinks attached to the Voltage Regs, but you'd have to open it, and it would need to be live (powered up and operating).

    If you're willing, I'd get a reading that way though (hopefully, you can see from the outside where you need to get a temp from, and even be able to read it through the fan as to not need to take part of the cover off, but it's not easy). If you do open it, just be careful not to touch any of the circuits if you do (capacitors can knock you on your rear, even after the power's been disconnected, as they store energy). So definitely while live.

    I know it's probably more effort than you'd hoped, but it's a sure way to tell if the software's not reading the temps properly (quite a difference between what iSTAT shows and the air output temp; 23C).

    That's normal.

    It's from one of the relays (2x; one clicks when wall voltage is attached to the IEC socket on the PSU, and the other is connected to the power switch on the front of the system and does the actual switching from on to off and vise versa as it can take the current).
     
  12. Rt&Dzine thread starter macrumors 6502a

    Rt&Dzine

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  13. nanofrog macrumors G4

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    #13
    :cool: NP. :)
     
  14. Trev311 macrumors member

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    Pumpkin Land
    #14
    So now that you guys have me fairly worried... I'm getting temp readings of
    67 and 54C for the two temp sensors in iStat on my 08(ambient is 18C and PSU fans are at 599RPM). I get that this is bad, but other than cleaning it out with some air, what can be done?

    Is it just a wait and it will die situation? I would guess that PSUs go out quickly if they are subject to too much heat.. Am I right in that guess?
     
  15. Rt&Dzine thread starter macrumors 6502a

    Rt&Dzine

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    #15
    I'm beginning think that these particular PSUs may have a sensor problem not a heat problem. I also checked the temperatures with Hardware Monitor. Pretty much the same as iStat. Then I checked the temps right after I booted up this morning when the computer had been off all night and they were 51 and 46C. Seems high to start. I've been trying to get an actual temperature with an IR thermometer. So far nothing higher than 42°. But I haven't opened the psu case yet. I'm too chicken. Ha ha.

    I'll keep you posted.
     
  16. nanofrog macrumors G4

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    #16
    I see it as software, as the reported temps could be wrong due to the software not reading temp sensors correctly (or possibly the temp sensor circuits are different from a different PSU manufacturer) data.

    That's why you want to get a temp of of the heatsinks inside the PSU. It will give you a real temp, and tell you once and for all, if the reading in the software is wrong or not.

    You could try to push the fan speeds as well if the temp reported is real. Beyond that, there's nothing you can do yourself if the temps really are high.

    The thing is, there's been problematic PSU's in the '08 MPs for sure, and its likely due to cost/supply issues. But I don't know of any way to tell them apart from one another. But IIRC, they did report higher temps, but I don't recall them being this high (originals in the low 40'sC, and the others <supplier shift> about 10C higher IIRC <same ambient and load conditions>).
     
  17. Rt&Dzine thread starter macrumors 6502a

    Rt&Dzine

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    #17
    You're right, of course. :) I was trying to avoid removing parts. So I'd need to remove the optical drive first?
     
  18. nanofrog macrumors G4

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    #18
    Yes.

    It's not the easiest thing to do either IMO, as you've got to pull it out to get the metal cover off. I'd be amazed if the cables have enough length to get a reading without having to put it back in it's location either (cover off).

    Don't leave it like this, or run it long either, as you'd likely have the fan removed. So get the temp quick. If you can leave the fan in and operational, DO SO. Even the cover being off changes the airflow characteristics.
     
  19. alphaod macrumors Core

    alphaod

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    #19
    My PSU is hovering around 60ºC right now, and has been like this since I bought the machine; I assume all machines have some sort of variation and mine just happens to run a bit hotter.
     
  20. nanofrog macrumors G4

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    #20
    60C is too high, given the heatsinks used in PSU's (small & thin = really cheap). Forced air cooling is used in combination to get the temps within acceptable levels, where the goal is 55C max (at full load).

    Under full load, you should only see ~40 - 45C, which extends the service life via reduced thermal stress. This is how they make it past their warranty period. Otherwise, they tend to go, given the low quality (i.e. least expensive possible) parts used.
     

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