Screen goes blank / black -- TiBook (PowerBook G4 DVI)

Discussion in 'Apple' started by sparty_3, Jul 15, 2005.

  1. sparty_3

    sparty_3 Guest

    On my TiBook, the screen has developed a nasty habit of periodically
    going blank. It "feels" more like a software problem than a hardware
    problem, but I'm not sure about that.

    I think that it may be software-related because, roughly 9 times out of
    10, putting the display to sleep and then waking it will cause it to
    come back, at least momentarily. Sometimes this trick will bring it
    back for a while (i.e. upwards of 30 minutes, sometimes hours) and
    sometimes it flashes back off after a matter of seconds. The computer
    is definitely still on because I can SSH in or use VNC just fine. Oh,
    and the keyboard and mouse remain completely functional even though the
    screen is blank. Also, switching display resolutions will make it come
    back at least momentarily (something I've discovered since installing
    VNC this morning), and putting the machine to sleep and then waking it
    will bring it back momentarily.

    The workarounds I've been using thus far are:
    1. SSH in, use pmset to set displaysleep time to 1 minute, wait a
    minute, and move the mouse. This has usually worked.
    2. VNC in. This works but is annoying, particularly as my PC display
    operates at a lower resolution than my TiBook display and I get
    scrollbars as a result.

    I have noticed while VNC'd in that the screen will periodically flash
    back on.

    I suspect that there could be something going wrong with the display
    cable, but I don't get any display corruption (which has been reported
    by others with that problem); I either get a clean image or nothing,
    and moving the screen between open and closed seems to have no effect
    unless I close it all the way and induce sleep.

    Any and all tips would be greatly appreciated, as this is extremely
    obnoxious. With VNC installed, I can at least use the machine (which is
    important as I have gotten attached to Mail.app and handle a lot of
    email for work), but having the machine actually work correctly would
    be a lot nicer.
     
    sparty_3, Jul 15, 2005
    #1
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  2. sparty_3

    James Meiss Guest

    .....

    Not sure I have any real suggestions but have you tried
    a) Booting from a system CD to see if the behavior still occurs?
    b) Resetting the PRAM?
    c) Resetting the PMU?
     
    James Meiss, Jul 15, 2005
    #2
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  3. sparty_3

    sparty_3 Guest

    Haven't tried that. I was actually thinking about trying to see if any
    of the live Linux CDs supported PPC yet, because booting to Linux would
    (IMO) be an even better option--if it doesn't happen under a completely
    different OS, then it's most likely software. If it does, then it's
    most likely hardware.
    Tried that, no luck.
    Tried that, too; similar results (no luck).

    Interestingly enough, hooking an external monitor to the DVI port via a
    DVI-VGA adapter results in both the external monitor and the internal
    monitor working. I had been unable to test that previously due to a
    lack of a DVI-VGA adapter (or a DVI-equipped monitor). However, once I
    hooked up the external monitor (via adapter) and hit the "Detect
    Displays" button in System Preferences->Displays, the laptop screen
    came up, and it then stayed up until I left for lunch. Both it and the
    external monitor went to sleep while I was eating lunch but came up
    promptly when I returned.

    I'm sure the external monitor working means *something*, but I'm not
    sure what (other than me being glad that I've been able to -- for now,
    at least -- solve the problem with a $13 purchase rather than a $200
    purchase on eBay, and without attempting major surgery on my PowerBook).
     
    sparty_3, Jul 18, 2005
    #3
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