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PowerBook Titanium black screen

Hi!
I got a PowerBook Titanium 1GHz via eBay. It’s got a black screen. Here are the symptoms:

TargetDiskMode works.
Booting up works. Boot chime is working. It seems to run the OS just as normal, but the screen stays totally black.
I do not see a faint image on the screen.
Caps look and Num-LED, volume buttons and volume feedback works.
Sleep works - I can (invisibly) activate the panel with ctrl-eject and then the disk stops, but no sleeping LED. I can awake it by pressing a button.
ShutDown works.
The charger LED changes between orange and green as you would expect..

External Monitor via DVI doesn’t work.

I did the reset PRAM routine and reset the PMU.
It does run with only one RAM slot filled.
I didn’t disconnect the PRAM battery yet.

One cold think the graphic chip is the problem, but wouldn't the TiBook complain at startup about that?

Thanks for your help,
Greg

Answers

  • Hi! Thanks for the post. This is an odd problem.

    When target mode is working, do you see the target mode symbol on the screen, or is the screen completely black? Based on what you're saying I'm assuming it's black.

    Lack of external video would tend to be evidence of a GPU issue, but these machines didn't have significant GPU issues. Make sure you connect the external video before powering on, because it might not switch over if you connect when it's already on.

    I don't think the PRAM battery would make a difference here. You mentioned resetting the PRAM, which is good, because sometimes the default screen brightness will be all the way down, and resetting the PRAM will return it to the normal value. But even if the brightness is down, you should be seeing a faint image, which you said you're not.

    I would verify you don't have a PRAM password by powering on with the option key held down, and see if you get a faint image of a padlock on the screen. But on the other hand, target mode should not work with a PRAM password, and you said target mode is working.

    Something is weird here, and it feels like I'm missing something. Are you saying it won't work with both RAM slots filled, i.e. that one slot is defective?

    The best thing I can suggest is that you open up the machine and make sure all connectors are securely fastened. This model has an inverter board connected to the optical drive, and the inverter cable would fairly commonly disconnect, so it's worth making sure it's plugged in. The video cable as well. Here's an iFixit guide that will take you through complete disassembly:

    https://www.ifixit.com/Guide/PowerBook+G4+Titanium+DVI+Display+Replacement/99

    Aside from checking the connections, it sounds like you've done all you can do without replacing parts. You might need to get another machine for that purpose. It could be a bad board or a bad screen, but you don't have the capacity to know that until you replace the existing board or screen with known-good parts. The DVI version of this machine starts at the 867MHZ version, so make sure to not get anything slower than that, or the parts won't be compatible.

    Let me know how it goes!

    Thanks,

    John



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