Help! MBPro fan constantly at max speed - how to find problem?

Discussion in 'MacBook Pro' started by MrAverigeUser, Jan 1, 2016.

  1. MrAverigeUser macrumors 6502a

    MrAverigeUser

    Joined:
    May 20, 2015
    Location:
    europe
    #1
    My daughters MBP 2009 2,53 Mhz Duo received a new main board (It is the one with only 1 fan) . So far, everything is ok.

    BUT: the fan is constantly turning at max speed from the start on, instantly when I push the "ON" button...

    I installed macsfancontrol and it shows LOW temperatures (30-42°C) everywhere, so there is absolutely no reason for max speed at all.
    The problem seems to be that there is no feedback about the rpm of the fan: Macsfancontrol shows all the time ZERO rpm although always at max speed. Evidently there is NO transmission of the fan speed… and I cannot change the speed because macsfancontrol gets no feedback about the rpm of the fan….

    My question (before purchasing a new fan) :
    Might it be a failure of the fan (rpm-sensor failure or the fan cable connector ?) or might it be more a problem of the main board?
    Is there anyone with experience about this problem?
     
  2. T5BRICK macrumors 604

    T5BRICK

    Joined:
    Aug 3, 2006
    Location:
    Oregon
    #2
    Try a SMC reset.

    https://support.apple.com/en-us/HT201295
     
  3. Queen6 macrumors 603

    Queen6

    Joined:
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    #3
    Generally if the fans run at maximum RPM on a Mac portable it`s a indicative of sensor failure. The problem will be determining which sensor has issue. You can try to run Apple`s hardware test or speak with an independent Mac specialist. Is the Logic Board still under warranty? if so speak with the vendor.

    IMO; Likely it`s the board as the fan RPM is derived from PWM not a physical sensor in the fan assembly.

    Q-6
     
  4. MrAverigeUser thread starter macrumors 6502a

    MrAverigeUser

    Joined:
    May 20, 2015
    Location:
    europe
    #4
    Thanks, but I forgot to mention that I did this already as first attempt - so this is sadly not the solution.


    Thank you a lot.
    This is exactly the Information I needed.

    MacsFanControl delivers the following data (rounded):

    Battery Point1 21°C
    Battery Point2 21°C
    Battery TS max 21°C
    CPU Diode 29°C
    CPU Proximity 26°C
    Left Palm Rest 21°C
    Northbridge Chip 28°C
    Northbridge Point1 27°C

    Disk Drives 24°C

    (all data resting as low as indicated)

    My question: Are there more than the above sensors?

    If there is "Northbridge1" indicated, there should also be at least a "Northbridge Point2" isn´t it?
    Might be here is the problem?

    Yes, the service who exchanged the main board has to give warranty - I sent him a message 1 hour ago but he hash´t yet responded. As he had finished the exchange of the main boards, the fan ran already at max speed. He told me to get a fan-App and adjust it myself….
    I regret to have accepted that - and not having forced him to do this himself…. I was a little bit too trustful as it seems… :-(


    "Likely it`s the board as the fan RPM is derived from PWM not a physical sensor in the fan assembly."


    I still don´t quite well understand how Macs Fan Control does calculate the rpm? Shouldn´t there be some data?
    ONCE now for not even a second it showed 178 rpm - only one time, I cannot reproduce this.

    Thank you for your kind replies… is there anything I could do myself ?

    At the moment there is nothing but coconut battery and MacsFanControl as Apps, the MBP 2009 runs under El Capitan.
     
  5. Queen6 macrumors 603

    Queen6

    Joined:
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    #5
    Nothing much you can outside of resetting the SMC. Yes there are multiple sensors, nor is all software aware of them. Bresink`s System Monitor will reveal the most in my experience.

    The application calculates the fan RPM from Pulse Width Modulation (PWM) if there is no data from the sensor the application can no longer calculate RPM, nor is the system able to set the fan RPM. Think of it like this the system does not increase fan RPM, rather it holds it down, therefore without any control the fan will run at maximum RPM by default, which is what you are observing.

    Q-6
     
  6. Gav2k macrumors G3

    Gav2k

    Joined:
    Jul 24, 2009
    #6
    You say the logic board was replaced. Is the fans connector fully seated? If the sensor cable isn't seated correctly no readings will be transmitted.
     
  7. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #7
    That's my guess, I had this problem with my Mac Mini when I upgraded the HD to a SSD, I failed to fully seat the temperature sensor and the fans just kept blasting at full bore
     
  8. MrAverigeUser thread starter macrumors 6502a

    MrAverigeUser

    Joined:
    May 20, 2015
    Location:
    europe
    #8
    Thanks again for explaining how this works.
    Well - hopefully the service changing the main board will call me back at least monday….

    I took a look at the fan cable connector at the begin - seams to be fully and correctly in the socket.
    Did not full off and back because I am not shure to add a problem caused by myself.

    Well - nevertheless the cable itself could be broken (it comes from underneath the fan so I can only see the last 2 cm with the connector…

    I have no original apple-DVD No. 2 with the AHT on it. After some search I found it in the Internet - but I could´t start it….

    Again - thanks a lot for your help.
     
  9. MrAverigeUser, Jan 2, 2016
    Last edited: Jan 2, 2016

    MrAverigeUser thread starter macrumors 6502a

    MrAverigeUser

    Joined:
    May 20, 2015
    Location:
    europe
    #9
    Well - I installed a new HD for the test… is there more than one sensor for the HD?
    As you can see above, MacsFanControl showed the temperature of "Disk Drives" at 24°C

    I think that should show that the HD sensor works isn´t it?

    Would be helpful to know how many sensors there are to check in the MBP (5,4) 2009 2,53 …
    With other words:
    Which sensors aren´t listed in the list above?
    Which sensor is missing ?

    edit:

    Finally I contacted the service who exchanged the main board. They will have a look at it on monday/tuesday - I will report about it when I got the MBP back.

    Thanks again for your very friendly help! :)

    and by the way...(forgot to write it before) : HAPPY NEW YEAR!! - for everyone here !!!
     
  10. MrAverigeUser thread starter macrumors 6502a

    MrAverigeUser

    Joined:
    May 20, 2015
    Location:
    europe
    #10
    So I brought in back the MBP, showed the Analysis of MacFanControl - and they promised immediately to present proper solution.

    I mentioned being now well-informed by the helpful members of this forum that the issue is NOT due to a fan problem, because there is no sensor in the fan… :D They even confessed to know that (Why for heaven´s sake did they nevertheless let me go with it the first time??? :mad: ) so they will perhaps put in even another main board or so….

    I will report about it…

    THANKS again for your kindly help!!!

    :)
     

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