G5 Thermal Calibration "CPU intake fan speed error. Check that inner door..."

Discussion in 'PowerPC Macs' started by serr, Mar 8, 2010.

  1. serr macrumors regular

    Mar 8, 2010
    Has anyone gotten to the bottom of this thermal calibration error with the G5? I see lots of discussion of a possible bug in ASD thermal calibration and claims that it can destroy the eeprom that stores the calibration info on the logic board.
    So what's the bottom line here?
    Does this error in reality indicate that the eeprom is no longer writable?
    Could this simply be an issue of the inner door not sealed properly (perhaps this calibration is critically sensitive to this)?

    The fans are racing as intended since the CPU's have been replaced and the calibration stored on the logic board is no longer correct. Everything is fully functional and passes all tests. The inner shield is in place and the sensor (by the rightmost tab) sees it there. The intake fan is running. I also tried another fan with no change. I suspect that some overly high sensitivity to the fan speed is not really the issue here.

    I have a dual 2.5GHz G5. The liquid cooling system is completely refurbished and the system passes ASD tests. I currently have ASD 2.5.8. I see reports of success using this version so there must be some hardware related issue here.

    I'd be most grateful if someone would share the trick or workaround for this.
  2. OrangeSVTguy macrumors 601


    Sep 16, 2007
    Northeastern Ohio
    Is there a red light on near the upper memory banks? That light will come on when the clear air baffle is removed or if the sensor isn't working. The sensor is in the bottom hole near the end where the clear baffle slides into.
  3. serr thread starter macrumors regular

    Mar 8, 2010
    Yes, as I said that system is working. The red light comes on when the shield is removed.

    I should mention that I have 2 identical G5 dual 2.5's and they both fail this calibration as described. I rebuilt these from 4 machines. I got 1 working CPU from each machine so there's no way to use an original configuration with the original calibration. My first web search made me say "oh no!" as this seems to be an issue many have had - that's why I mentioned the rumors I've read. (actually, I said something else)
    The room temp here is about 69F. Should I try this in a 50F or 60F room?
    When I fire up OSX and run temp monitor, it shows the CPU's at 38C, 32C for unit #1 and 29C, 30C for unit #2.
    The radiators and everything are clean.

    I've had experience before with programmable chips that are a bit flakey and need slightly different power for write mode. Could that kind of madness be going on with these logic boards with the ROM chip in question? Or is it more of a trick with setup conditions (temperatures, etc).
  4. photonorm macrumors member

    Mar 2, 2011
    Memphis, TN
    I am also at the same place you are...or there abouts. I just overhauled my dual 2.5, ran ASD and got one pass and one error on the processors. The error was 'tafs is out of range'. My idle temps are 133/55 range with peaks at 185-200 range when on a full load for 5 min.

    I am not sure what the correct temp values should be and what is considered 'too hot'.

    My fans are rather quite at idle and spin up when under load. I don't know how to check the fan speeds, but wish I could.

    You can read up on my LCS repair at http://forums.macrumors.com/showthread.php?p=12175560#post12175560.

    Maybe we can assist each other. I will subscribe to your thread and follow the posts.

    FYI with regards to your original thread questions: I don't know about any bugs in the ASD software.

    On the first boot after putting the LCS back in place the fans would be at a constant spin of at least 50%. Not the jet fighter power when there is a kernel panic. The machine was operating normally, excepts for the fans. The intake fan seemed to be running at a higher speed than the others.

    After the Thermal Calibration test and restart the fans were running much slower and would spin up on processor load. All things might be working as designed but the high temps and the error on the TC has me looking for answers: What does the error mean and what are the temp values suppose to mean.

    Hope that helps in some way. If you can offer assistance with my questions please post.

  5. bengi macrumors member

    Jul 21, 2011
    thermal calibration

    I got the message on CPU input fan etc... while I was testing two CPUs fixed sodering some ceramic SMD witha known good lobo. After that the G5 refused to boot.

    Today I put back the original processors and the G5 works, so the thermal calibration does not damage the lobo.


    PS I am new to this forum, will present myself in the appropriate section, thanks
  6. QuadMacUser macrumors newbie

    May 19, 2012
  7. drorpheus macrumors regular

    Nov 20, 2010
    the only way you damage the eeprom is if you lose power while the calibration is being written to it and even at that you can still rerun the calibration. the original error in the post from last year is because the fan is struggling to keep up, the CPU0/1 TAFS Out of Range means you need to reapply new thermal grease because the cpu is getting too hot (out of its comfort zone). What is the exact problem or error your getting?
  8. bengi macrumors member

    Jul 21, 2011
    The reason why Apple services do not want to fix these machine (even for customers willing to pay) is the odd behavior of the thermal calibration process, they told me that you need to try with several processors before getting two calibrated.
  9. mgaa80 macrumors newbie


    Jun 21, 2015
    Hi guys - here is the solution:

    the 'CPU0 or CPU1 Intake Fan Speed error' is not neccessarily related to the intake fans :(. Its apparently (based on my researches) also related to the PUMP of the LCS cooling. I overhauled my LCS also - and I crashed the pump - its now stuck on full speed (I read something around 4500 rpm). Full speed is unfortunately higher than the speed Apple allows (I think something around 3600 rpm) - so its showing this error.

    If I do the thermal calibration with a good pump it passes the calibration (but in my case now its showing the processor gets to hot...maybe a problem specific to my situation now.

  10. JRDN macrumors member


    Oct 24, 2015
    I got this error repeatedly when I, too, overhauled my LCS.

    Check the processor sockets on the LB. I had a bent pin on my CPU A socket. Got in there and made it look like the surrounding pins and then ran thermal cal. Came out fine! Try reseating your processors and check for bent pins

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