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Thread: PowerBook G4 backlit keyboard not functioning after upgrading to Mac OSX 10.5.8

  1. #1
    Join Date
    Apr 2012
    Posts
    52

    PowerBook G4 backlit keyboard not functioning after upgrading to Mac OSX 10.5.8

    My brother gifted me PowerBook G4 laptop and its real fun having it with me. I keep on using it the whole day and you know it never created any sort of problem until I did any kind of modification in it. Recently I upgraded the Mac OSX 10.5.8 and I think the upgrade didn’t suit the system resulting in some weird kind of issue all the time. However after I did the upgrade I found that the backlit keyboard was not functioning. Tried all the possible solutions give to me till now but none of them worked. Instead I can say that as much as I try different solutions I make myself sure that the problem is becoming too serious.

    Let me tell you that i have already checked certain thing in my machine and made sure that there is nothing into the system that has disabled the backlit function. The keyboard has not be turned off thought f8 key neither the F8 is toggle to ON or OFF nor F9 & F10 are increased or decreased. Overall I just need to say that I have already tried out all these three button combination and also other possible solution given to me (I can’t paste those suggestion give to me as they are too large to be pasted here… ), I am sure that the backlit keyboard is still working. Reason for being so sure is that the number lock and the caps lock buttons are still working well and fine. I strongly doubt that there is something that has been crashed after I did the upgrade to Leopard. But confused due to multiple thought, please help me out and clear my doubts, is that my backlit keyboard working properly or do I need to take it to the care center for the repair?

  2. #2
    Join Date
    Jul 2011
    Posts
    1,795

    Re: PowerBook G4 backlit keyboard not functioning after upgrading to Mac OSX 10.5.8

    If your backlit keyboard is not working or if the option to turn the keyboard ON or OFF is not appearing in the keyboard and the mouse control panel could be most probably due to either of the reason i.e. either hardware or software issue. I guess if you thoroughly search for the same issue you might end up getting multiple number of treads related to this same issue, before proceeding just try searching for the solution for this issue on web and then think of doing something else.

    Anyways if you facing the backlit keyboard malfunctioning issue they you can probably try out resetting the PRAM and the PMU. And for resetting the PRAM you need to simply follow the following step:
    • First shut down the System
    • Now try to search for the mentioned keys on the keyboard, keys are: Command, Option, P, and R. you need not have to do anything with these key with the system turned off but it has to a lot after turning on the machine.
    • Anyways now turn on the machine and now press and hold the all those three key combinations that I mentioned above i.e. Command-Option-P-R keys. Make sure that you press and hold these key combinations until you notice a gray screen appears on the display.
    • Now hold down until and unless the computer is restarted completely until you hear the startup noise twice. Once you hear the start up sound for the second time just release those keys.

    Everything is done now, the computer’s PRAM and NVRAM are now reset to the default vaules and also the clock settings may or may not be reset to the default date on some of the computer models.

  3. #3
    Join Date
    Jul 2011
    Posts
    1,576

    Re: PowerBook G4 backlit keyboard not functioning after upgrading to Mac OSX 10.5.8

    As already told in the above post that if resetting the PRAM and NVRAM doesn’t resolve the issue then you might have to reset PMU too i.e. Power Management Unit. PMU is nothing but an integrated circuit or you can say computer chip that is normally found on the logic board of the PowerBook and iBook. This integrated chip actually controls backlighting, hard disk spin down, sleep, wake, some charging aspects, trackpad control, and some of the input output.

    As now you must have understood that PMU is somehow related to the backlight aspect of the system then definitely if anything happens to the PMU can surely result or show an impact on the backlit in some of the other way. or you can also say that if anything happens to the backlit then there are chances that PMU must be the core reason for the cause. Anyways coming back to the issue, now at least you must have understood the relation between PMU and the backlit keyboard. Now if you need to make sure that the issue has nothing to do with the PMU then better you try to reset PMU in your machine. If the problem is resolved by resetting the PMU then understand that PMU was itself the main cause for the problem and if the problem is not resolved then unfortunately you will have to go for something else.

    For resetting PMU in PowerBook G4:
    • First you need to make sure that the computer is turned off; if the system is on simply turn it off.
    • Now press and the release the reset button that is located on the rear panel of your machine. This reset button is between the external video and the modem ports.
    • Now wait for few seconds say for 5 to 10 seconds and then press the power button in order to restart the computer system. If the issue is resolved then the backlit keyboard will start functioning.

  4. #4
    Join Date
    Jul 2011
    Posts
    1,573

    Re: PowerBook G4 backlit keyboard not functioning after upgrading to Mac OSX 10.5.8

    If that does not work you can try creating a new user account then log-in to that account and see if the backlight works.
    Next try deleting the following files: Macintosh HD>Library>Preferences>com.apple.BezelServices.plist and along with that also Macintosh HD>User>Library>Preferences>com.apple.BezelServices.plist. Once you find both the files just drag both to the trash and then restart your machine, remember that both the files that I have mentioned above are the preference files and you cannot delete these files unless they are not at all in use. So therefore to delete them first you need to restart, now the system will automatically regenerate two new files. Once you are confirmed that the files are completely regenerated delete the old copies of the same files. Check your keyboard backlight is there a check box in the keyboard and mouse control panel. And If the backlit is still not functioning then I personally feel that there are least chance of the keyboard backlit functioning. If you are done with trying out all the above suggested solutions and if still the issue same with no big difference with respect to the keyboard backlight also with the checkbox in the Keyboard and Mouse control panel then surely the issue has something to do with the hardware failure. Better you contact AppleCare and make sure that you get the issue fixed from them. there might be the case they say that some of your software related to the backlit has gone corrupt and you need to get them again. Don’t just get half information, for a safer side its better recommended to get a complete information about the issue.

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