iMac 27 I7 with random black screen issue at startup of Windows 7!

Discussion in 'Windows, Linux & Others on the Mac' started by Darkozon, Oct 12, 2010.

  1. Darkozon macrumors newbie

    Oct 12, 2010
    Hi, I'll try to explain the my random black screen issue as best I can.

    I have a boot camp partition with Windows 7 x64 Ultimate installed.

    I used the USB method to install, all goes well and Windows 7 gets installed, I update drivers, install boot camp etc. all is good, right!

    My problem is that everything seems to be in working order, but the built in LED screen will only get lit/active in 1 out of 5 times at startup of Windows, eg. the built in screen stays black/off (black screen issue), like the install issue on iMac 27 I7 w/ATI 4850.

    NOTE! When booting OS X the built in LED screen gets lit/active on every startup.

    So what I did was connect a second LCD monitor via Display port to DVI, this monitor/screen has no issues, it gets lit/active on every startup of Windows, even if the built in screen/monitor stays black/off (black screen issue).

    NOTE! I have tested both the latest drivers from Apple (10.4 19/MAR/2010, found on the USB install method) and AMD ATI Catalyst Driver (10.8 25/AUG/2010). The issue remains on both Apple released drivers and AMD ATI released drives.

    1. So to me it seems like there are some detection/communication issues between the built in monitor and the video card on Windows 7, as there is no issue detecting and activating a monitor connected to the display port.

    Am I or we missing a monitor driver in Windows that OS X has, or is this a hardware issue that Apple knows about and compensates for in OS X with on load firmware, driver or a kernel fix?

    2. Or do you guys think its an hardware issue only found on my iMac?

    3. Does anyone else have this issue on their 27" iMac Late 2009 I7, ATI HD 4850 machine?

    If yes, did you manage to solve it?

    Thanks for any help on this issue.

  2. Darkozon thread starter macrumors newbie

    Oct 12, 2010

    Hi, I've seem to have found out the source of the problem.
    The issue is related to heat, and an iMac 27" gets hot pretty fast.

    If I boot the iMac straight after first start into Windows 7 I seem to get a lit built-in display at all times. I can also boot OS X first and then into Windows 7 and the built-in screen get lit every time as long as the iMac isn't hot.

    Strange thing is that the monitor connected to the display port gets lit every time. So I can only assume that the heat only interfere with output to the built-in LED screen.

    So this iMac is going to an Apple premium reseller for service, and I'll tell you guys how it went.

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