external monitor flashing/blanking with PB plugged in

Discussion in 'Macintosh Computers' started by sdebnath, Mar 8, 2005.

  1. sdebnath macrumors newbie

    Mar 8, 2005

    So I recently bought a Dell 2001FP off my friend, and ran in to the problem where my LCD (connected via DVI) started blanking/flashing at 1600x1200 resolution. I did a bit of research and found several sites saying that this particular LCD has problems with doing 1600x1200 via DVI.


    However, here's the twist. This only happens when my powerbook is plugged in to the AC adapter while the LCD is connected. If I disconnect the power source to the powerbook (running off battery while LCD is plugged to the wall), the LCD stops flashing. At first I thought that it might be a problem with the particular socket, but nope, tried all the sockets, and still the same problem.

    Bought the powerbook January '04, and it is running Mac OS X 10.3.8. 1.25GHz proc, w/ 512 MB ram, ATI Radeon (for sure) 9200 (?) w/ 64MB video ram. Updating drivers from ATI's support site didn't help either.

    Stuff from system profile:

    Type: display
    Bus: AGP
    VRAM (Total): 64 MB
    Vendor: ATI (0x1002)
    Device ID: 0x4e50
    Revision ID: 0x0000
    ROM Revision: 113-xxxxx-117

    Anyone else ran into this problem? If someone has anything that I could try I am up for it. Not sure but if I connect it with a VGA cable instead and then use the Apple's DVI adapter, would that help any? possibly settle timing issues between the card and lcd. But then again why is it only when my powerbook is plugged in?

    Shawn :confused:
  2. Monk Edsel macrumors regular

    Apr 7, 2004
    I don't see how it is possible for you to correct the problem by unplugging the PowerBook from the AC, because if you unplug a PowerBook with an external display attached, the PowerBook automatically goes to sleep and will not reawaken until the AC is plugged back in, or you disconnect the display.
  3. blodwyn macrumors 65816

    Jul 28, 2004
    Portland, Oregon
    This is incorrect, I just pulled the power plug on my PB which is connected to an external display, and it carried on working as normal.
  4. Monk Edsel macrumors regular

    Apr 7, 2004

    "Connecting an external monitor increases the power requirements of the PowerBook. Therefore, you must use the AC adapter whenever the PowerBook is connected to an external monitor. The PowerBook will not wake up if the power adapter is not connected, and if you disconnect the power adapter the computer will go to sleep."


    My PowerBook does indeed exhibit this behavior. Thoughts?
  5. blodwyn macrumors 65816

    Jul 28, 2004
    Portland, Oregon
    Don't know why there's a discrepancy, I'm currently typing this entry with an external monitor connected and my power unplugged - 12" G4 1.33GHz running 10.3.8.
  6. Mechcozmo macrumors 603


    Jul 17, 2004
    I connect all the time to an external monitor while on battery power. No issues. mini-DVI to VGA then VGA extension cable to projector. Oh, yeah! :D

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