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Which ASD version for Mac Pro 1.1 (2007)?

Discussion in 'Mac Pro' started by shaocaholica, Jun 6, 2010.

  1. macrumors newbie

    I'm trying to service a family Mac Pro and I'm not close at all to an Apple Store. Also, the machine is not under warranty anymore. I think I have a faulty thermal sensor on the northbridge. Its giving 129C readings from a cold boot and I've already cleaned the heatshink and reapplied thermal compound. Running AHT throws an [4SNS/1/40000000: TNOH] error. Resetting the PRAM and NVRAM didn't do anything. I'm not sure if ASD can do any more but its worth a shot right? Does anyone know which version I should look for to use with this 2007 Mac Pro 1.1?
  2. macrumors 68040


    AFAIR it will be 3S116. But AHT told you everything that you need to know: 4SNS indicates sensor, TNOH indicates which one: NOrthbridgeHeatsink. Look here: http://discussions.apple.com/message.jspa?messageID=7268348 This is exactly your problem - ultra fast fan speeds and abnormal Northbrigde Heatsink sensor readout.
  3. macrumors newbie

    Thanks, I'll download that one. As for the thread you linked, they never really solved the problem. I've tried resetting the PRAM, NVRAM and SMC.
  4. macrumors 68040


    Where is this sensor exactly placed? On HS or logic board? I asked about it (cause i didn't remove NHS im my MP yet) in this earlier thread you started, remember?
    From what i know, no reset (or other trick) will fix this issue, only replacing sensor/or entire part where it is mounted/ will do. I wish you, that i'm wrong.
  5. macrumors newbie

    There is a sensor attached to the Northbridge heatsink and I've tried disconnecting it but even with it disconnected, OSX still reads 129C. Although I just realized that high temp reading from a thermal probe is equivalent to an open circuit which means disconnecting it is essentially giving it a max reading! Hmm. I might have the fix!
  6. macrumors 68040


    This makes sense. You're on the right way, i think. Fix will be much cheaper than logic board replacing.
  7. macrumors newbie

    Well, I can either replace the sensor or put a dummy in its place (resistor). I can't seem to find the part by itself online. I could replace it with another type of sensor but there's no guarantee it would operate in the same output range. If anyone knows where I can get a replacement sensor without buying a new mother board, please tell.
  8. macrumors 65816


    Contacting Apple would likely get you the "new logic board" rundown, however the right genius might be able to lead you somewhere if you get him away from the group. Also, local repair shops that are Apple certified are not bound by their terms, so they might be more willing to give you a hand (mentally.) My guess is that the part is not available by itself, because standard procedure would be to replace the whole logic board for sensors on the northbridge.
  9. macrumors newbie

    The sensor is actually removeable and attached to the northbridge heatsink. However, I couldn't even get a part number for the heatsink so apparently Apple's policy is that all those things are part of the main board even if they are trivially easy to replace independently. Anyway, the thermal probe is probably just a run of the mill 10k thermistor. Thats what I'll replace it with (~$2) and if that doesn't work I'll just replace it with a dumb resistor.

    As it turns out, an open circuit on a thermistor is actually a really really low temperature but it could also mean the thermistor is absent or failed so the engineers actually accounted for that and instead of reporting -40C, it reports the MAX temp as a failsafe.

    IMO, the probability of a failed thermistor is high enough that it doesn't make sense to assume the worst that the system is overheating.
  10. macrumors 68040


    Maybe then finding dead 1.1 or 2.1 logic board will be your chance to get original spare sensor.
    Try also contact Apple tech service (like Techhie did mention). If you'll be lucky, maybe some kind tech will help you get right part for replacement. Miracles sometimes could happen ;) Good luck and keep us posted.
  11. macrumors 65816


    I've seen a few of them floating around on eBay, but most want ridiculous amounts for them (>$150)

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