5 Replies Latest reply: Dec 28, 2009 9:14 AM by Allan Jones
Phillip Anthony Level 1 (60 points)
I have been trying to brighten my old PB's dim monitor, but most Knowledge doc's indicate a Model Number is needed to proceed correctly with a PMU reset. I just completed a PRAM reset but that did not help.

Can someone please tell me how to find the Model number of my computer?

I have taken the battery out and there is no Model Number in it's cavity underneath the computer. I have also looked in the Pref's again without finding a Model Number.

I purchased my G4 17" 1.33 Gh PB in December of 2003, if that helps. Any help will be appreciated.


17" PowerBook, 24" iMac, Mac OS X (10.6)
  • Allan Jones Level 7 (33,680 points)
    The processor speed and screen size should be all you need to get the instructions in this Knowledge Base document:


    The link should open at the point in the document that addresses your model. If not, this is what is says for your model:

    1) If the computer is on, turn it off.
    2) Reset the power manager by simultaneously pressing and then releasing Shift-Control-Option-Power on the keyboard. Do not press the fn (Function) key while using this combination of keystrokes.
    3) Wait 5 seconds.
    4) Press the Power button to restart the computer

    You don't have to enter a model number into the computer before resetting the PMU.
  • eww Level 9 (52,975 points)
    Go ahead and reset your PMU, but I don't think you're going to see any appreciable brightening of your old display backlight. Dimness is a product of the fluorescent tube's aging, and it's not reversible.
  • Phillip Anthony Level 1 (60 points)
    Hello Alan,

    Thanks for the help.

    The Knowledge Doc that you linked me to was the same KD (Title anyway) that I was perusing. And somewhere in there it wanted a Model Number. Anyway, all of that is history.

    I just finished the PMU reset and the monitor brightness may have perked up just a trifle, but that may just me dreaming that it did. In truth, I have absolutely nothing to compare it to, so it is what it is. And, add to that the fact that I have recently purchased a refurbed 24' iMac whose monitor brightness nearly gives me a headache. Am now using Shades which helps a lot.

    Back on topic: My old PB is still useable for my photography and travel, so this is not the end of the world for me - or it. Just old age setting in. Happens all the time.

    I appreciate the help.


    PS. How's the snow at your end??
  • Phillip Anthony Level 1 (60 points)
    Hello eww,

    Thanks for your help.

    As you noted, not much change in my monitor brightness after the PMU reset. My PB is just past it's prime. It is however, still usable which is good.

    I appreciate your comments.

  • Allan Jones Level 7 (33,680 points)
    Have you tried going to System Preferences > Displays and hitting the "Color" tab. You can re-calibrate your monitor from there, overriding current profiles to make the image brighter. As you are crunching images, you may prefer to beg or borrow a "spider" color calibration unit from a co-worker to get a proper profile. If you simply need brighter--if not correct--color, the Displays prefs may be the best path.

    The pre-programmed color profiles on my PB17 (10.4.11) are all brighter than the one I created. Try those before creating a new one.