Laptop "reverse dimming". Dark when plugged in, then bright when unplugged

Discussion in 'Windows 7 Help and Support' started by optical, Aug 4, 2009.

  1. optical

    optical New Member

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    Hey all I'm having a majorly annoying problem

    Every day or two, Windows 7 is REVERSE dimming on me and I can only fix it with a reboot.

    What I mean is, suddenly when the AC Adapter is PLUGGED IN, the screen will be DIM (Even though control panel shows it as max brightness on the slider). But then once I UNPLUG the adapter, the screen is bright like its supposed to be..

    For the life of me I can't figure it out, but it's driving me to the point of insanity because I keep having to reboot so often.

    Googling the problem finds another person with the problem, but of course, the post has 0 responses.

    Hopefully someone can help

    Thank you in advance!
     
  2. jeradw

    jeradw Senior Member

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    Check your ambient light sensor settings in the BIOS.
     
  3. cab1024

    cab1024 New Member

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    How do you do that? And what should it be set to?

    I'm having the same problem and its extremely annoying to reboot so frequently and needlessly.

    My Dell Inspiron e1505 does not have a ambient light sensor that I know of...
     
  4. cab1024

    cab1024 New Member

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    I went through all of the settings in the BIOS, but there was nothing about an abient light sensor, or anything ambient. There were two default brightness settings ( for battery and powered) but they were set to maximum already.

    I wonder if this has anything to do with the sole other major annoyance with Win7 so far, that the laptop does not always wake up properly from being closed or asleep. The screen does not come back on. I can hit the power button and put it back to sleep, but it still doesn't come back on waking it up again.

    The only recourse is to hold down the power button until it reboots. Not the ideal way to continually reboot a brand new OS installation. And I lose any work that was unsaved when I walked away, along with all my open browser tabs.

    Any ideas? This is a major problem as far as I'm concerned, and it is clearly affecting many other users. MS should address this ASAP!
     
  5. Saltgrass

    Saltgrass Excellent Member
    Microsoft Community Contributor

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    Does it work as advertised when on battery power? Do you have another power adapter you could try?

    Have you checked the advanced power settings? I do not have a laptop, so I do not have the options for on or off battery.
     
  6. cab1024

    cab1024 New Member

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    I'm 99% sure it's a software issue, not a problem with the hardware. I never had the "reverse dimming" issue with XP.

    I did have problems a LONG time ago with the screen not waking up along with the rest of the computer, but I was able to find the figure out what the conflict was online and did not have the problem again until I wiped the hard drive and reinstalled XP a couple of months ago. After 2 or 3 days of trying find the hack again, I realized my time was too valuable to waste any more time on it -- so I bit the bullet and wiped the drive again and installed Win7.

    So you can imagine how frustrating it is to have it reoccur occasionally AGAIN. After all, this is two OS's later. I'm fairly certain it's a conflict of some sort with the software I'm running. The thing is, I haven't installed all that much stuff yet, sot to have problems this early on does not give me much confidence in the future with Win 7. That said, the PC runs a hell of a lot smoother than it did with XP, and I'm glad I skipped Vista. But I'm not going back.
     
  7. cab1024

    cab1024 New Member

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    Any ideas?
     
  8. saulw

    saulw New Member

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  9. jbarrington

    jbarrington New Member

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    Here's my story and a variation to the possible solution that might help somebody as well...

    I just had a similar issue happen with my Toshiba Satellite laptop with Win7 64bit installed.

    I had my laptop plugged in, but I needed to unplug the power adapter from an outlet while it was still plugged into my laptop, and go to another location of my house. When I plugged it back into an outlet, the screen went completely dim. The laptop screen was fine during the boot-up process and when Windows starting booting up as well. When it came time for it to reach the log on screen, the screen went dark.

    I searched the web for a solution, but many "solutions" on different sites pointed to the power management as being the issue. It didn't work for me.

    One suggestion said the BIOS settings might be set to FAST boot. I tried that but it had no effect on the problem. Then I had issues with trying to undo the Fast boot process because I couldn't get to the BIOS. Then I finally found the solution here by holding down the F2 key before pressing the power button. I set the fast boot setting back to normal and rebooted.

    WOW! Everything somehow went back to normal again. I could see the windows screen WITH the power plugged in again. Somehow this fixed my reverse dimming problem within Windows 7.

    Somehow,
    -setting the fast boot setting within the BIOS from NORMAL to FAST,
    -saving the BIOS setting and exiting,
    -completely rebooting back into windows and shutting back down again,
    -then rebooting back into the BIOS and setting back from FAST to NORMAL again

    This corrected my issue.
     
  10. CompGuyNextDoor

    CompGuyNextDoor New Member

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    Hey - For anyone experiencing this annoying phenomenon,
    I had the same issue with my Dell Inspiron 640m.
    Was driving me crazy, afterall, when you're on battery power, that's when you would want to dim the screen to conserve energy...

    I figured out that the dimmers actually have (2) settings. One, when the A/C adapter is plugged in and the second, when it's on Battery Power!

    So, with the adapter in, Adjust your Screen Brightness to fairly bright and then
    unplug the A/C adapter and adjust the Brightness to a Dimmer Setting.

    Test by plugging the Adapter IN (Bright), Out (Dim).

    I hope this works for your situation.

    Take Care

    MikeV
    (ComputerGuyNextDoor.com)
     
  11. scotallen

    scotallen New Member

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    Hey sorry late than never.. I just fixed the prob on my PC. I have a Dell Inspiron 1720. Had the same prob for about 2 weeks. Go into the BOIS (F2 @ boot most likely) go to video settings. Select the tab for Plugged or battery power. Not sure how it got changed in the first place. Hope this helps someone. The fast/normal boot did nothing for my PC
     

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