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      Unable to Increase Brightness using functional keys - IdeaPad Z500, Z400

      Symptom

      Brightness function keys +/- cannot increase the brightness on display. Other function keys are working properly.

      Affected configurations

      The above symptom may occur to the following systems:
      IdeaPad Z500, Z400

      The above symptom may occur under the following operating system:
      Microsoft Windows 7, Windows 8.1

      Solution

      The issue is most likely related to a windows update that has upgraded the graphic video driver to version 10.18.10.3958 from 9/30/14 or 10.18.10.4276 from 8/17/15. These versions are known to cause loss of brightness control. Restoring the previous driver should also restore brightness control.

      1. Go to Device Manager
      2. Select Display adapters and scroll down
      3. Right click on Inter(R) HD Graphics4000 and select Properties option
      4. Go to tab Drivers in the pop up window
      5. Push the Rollback Driver button
      6. Wait until it is done. Your system should recover the brightness and the increase/decrease functions in the keyboard.
      7. If the previous step does not resolve the issue, please upgrade Intel Video Driver to the latest.
        1. Windows 7 Intel Video Driver: Download here
        2. Windows 8.1 Intel Video Driver: Download here
      8. Check to see if brightness controls have been restored using the brightness keys.

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      • Alias ID: IN20130916-002
      • Document ID: HT079345
      • Last Updated :26 Nov 2015
      • © 2015 Lenovo