ibook pmu-battery communication problem?

Discussion in 'PowerPC Macs' started by jahbug, May 23, 2006.

  1. jahbug macrumors newbie

    May 23, 2006
    Hi all

    A sudden problem has just developed with my 14.1 in iBook 16 vram. The computer (power manager?) can no longer communicate with the battery. I have swapped a reserve battery to prove that it is not the battery that is causing the problem. I tried resetting the pmu a few times, but I don't think that's working, since when I try to reset the pmu, and then restart, it doesn't reset the clock. Whenever I unplug the power cord, the clock does reset to 1969 (this is presumably due to the computer's failure to communicate with the battery). But with the power cord plugged in, after attempting to reset the pmu, the date does not reset. Therefore, I am guessing that I have not yet successfully reset the pmu. I used the shift-control-option-power keystroke combo, and tried it now 3 or 4 times without apparent success. The battery manager on the menu bar registers "70%" for battery charge - even though the battery is not accessible - for whatever that's worth.

    Thanks for any help!
  2. mad jew Moderator emeritus

    mad jew

    Apr 3, 2004
    Adelaide, Australia
    Okay, well read this if you haven't already. Also, are you sure the keys you're using are independently working properly? :)

    Never reset the PMU more than once between restarts, too.
  3. jahbug thread starter macrumors newbie

    May 23, 2006
    yes, the keys are all working, and yes, I checked that page. thanks!

    I am wondering if there is any way to do a pmu reset at the command line prompt.
  4. mkrishnan Moderator emeritus


    Jan 9, 2004
    Grand Rapids, MI, USA
    There is, but not at the Unix command prompt -- at the Open Firmware command prompt. This method may reset some other firmware that the other method doesn't reset.

    Boot into Open Firmware (hold cmd-opt-O-F during boot)
    Type the following, exactly as it appears, each line followed by <return>:


    The computer should then restart.

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