Powerbook power adapter keeps switching on and off

Discussion in 'PowerPC Macs' started by billyb, Oct 4, 2009.

  1. billyb macrumors member

    Apr 26, 2003

    I have a 12" Powerbook 1 ghz (yes, it's getting old) running Tiger. When it's turned off, it charges just fine. However, when the computer is on, the power from the adapter keeps cycling on and off. For example, the lighted band around the power adapter tip switches from orange to off (NOT to green) repeatedly: about 3-4 seconds with power (lighted band is orange, screen backlight is bright, and if I'm in the Energy Saver section of the System Preferences, it thinks it's plugged in) and about 1 second with no power (lighted band is off, screen backlight dims, and if I'm in Energy Saver area, the computer thinks it's on battery power.

    This is irritating because 1) the computer won't charge when on, and 2) as I type this, the screen goes from bright to dim to bright to dim etc.

    Obvious answer is the power adapter, but I don't have access to another. What does everyone think? is it the adapter or some other problem?

    FWIW, the internal hard drive just died and I'm booting from an external FireWire drive. It started doing this power thing a few days before the internal hard drive died.

    Thanks for any help you can offer!

    - bb
  2. airplaneman macrumors 6502a

    Jun 8, 2009
    I would bet it's the adapter. It might also be the SMC...
  3. billyb thread starter macrumors member

    Apr 26, 2003
    One more data point

    One other thing to add to my original post. If I take the battery out and just try to run on AC power, the indicator ring on the power tip lights up green. However, after the startup chime, the computer makes it to where the little circle is spinning around while booting up (about 10 seconds after powering on) and the whole thing shuts off.

    I think this is consistent with the power adapter being the problem (definitely rules out the battery). Don't know what an SMC is but will look it up.

    - bb

    EDIT: Looked up SMC and I think my computer's too old to have either an SMC or the earlier SMU. Think mine may have a PMU instead and I'll try resetting it when I get home tonight using SCOP (http://en.wikipedia.org/wiki/Power_Management_Unit).
  4. leodavinci0 macrumors 6502

    Jan 26, 2006
    Perhaps the connection for the power supply, the plug that goes into the computer, will lose connection intermittently from a dirty contact ( I have this on my old 867 MHz PB). This can be remedied for a while by twisting the plug around while plugged into the computer. If it really goes in the cycle you describe perfectly timed as you described it, then you know this isn't actually the issue. I have a similar issue with one of my two batteries causing a charge, not charging, charging cycle repeatedly until it is charged. In this case, I know it's the battery since the other doesn't do it.
  5. sharpeiboy macrumors newbie


    Jan 14, 2008
    Having same problem now - find a solution?

    I'd love to know what you figured out. I'm having the same problem.
  6. zildjansg macrumors 6502

    Jan 10, 2010
    Since it talks about powerbook and its AC adapter,my case is that when i remove the battery of my powerbook G4 "15,and plug in directly,it wont turned on..but if with battery(obviously,aside from chargine) it will turned on..how on earth that happen when i used to plug directly nothing comes out.

    any advice or tips?


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