02-06-2012 04:09 AM - edited 02-06-2012 04:12 AM
my ThinkPad shows a strange behavior... Suddenly the screen brightness was reduced by the system. Brightness is "15" but it is darker than before. I can not find any option to raise brightness!!!! I am using a Lenovo power supply unit.
It is annoying to use the ThinkPad at daylight. Really exhausting looking at a screen thats too dark.
02-07-2012 07:51 AM
Some basic questions...
If you reboot to windows and are on AC is the screen still dim? Does it respond at all to screen brightness increase / decrease settings?
If you restart and go into BIOS on AC, how bright is the display? Any different than in Windows?
If the problem seems isolated in Windows, I would reload the power manager and hotkey drivers and recheck the settings in power manager for screen brightness.
07-06-2012 08:32 PM - edited 07-06-2012 08:39 PM
It seems like I had the same problem.
Just for the record: I usually use the system with AC (fixed-line power) and with brightness on 100%. I know all the ways to set the brightness, don't worry.
One day the brightness of my screen was suddenly reduced. Must have happened while the system was on. It was on setting 15, but definitely darker than before. I could still decrease the brightness further by chosing 14, 13, 12 and so on. But 15 was already pretty dark. However, when I was inside it was not so dark that I could not read anything, so I suspect some power saving option to have caused the problem. The interesting thing is that the brightness while in BIOS and during the glowing windows logo startup animation seemed to be normal (100%). Only when the logon screen came on it got dark. So it must have been a software issue.
I did have the Lenovo ThinkPad Power Manager running before, which was set to reduce the brightness during logon and logoff. I turned it off in hope of fixing the problem, but to no avail. I turned the Power Manager off the following way: I stopped the program and then used msconfig to prevent "ThinkPad PM Service" (in "Services" tab) and "ThinkPad Power Manager" (in "System Start" tab) from starting with Windows. "Varibright" in the AMD Catalyst graphics driver, which also messes with the brightness, was never on in the first place.
As this didn't fix the brightness and also (not sure whether before or after my messing with the Lenovo software) the hotkey screen display didn't work anymore, my plan was to reinstall every piece of Lenovo software that had something to do with hotkeys and power management (thanks, Mark!). Today, however, after a few days of working with the dark screen and just shortly after startup, the brightness suddenly returned to 100%! The hot key display issue has not been fixed, not sure what to do now. I'll probably reinstall the Lenovo software.
Lenovo ThinkPad Edge 13
Windows 7 Pro 64 bit
07-14-2012 07:03 PM
After I have re-enabled the services I had disabled with msconfig before, the hotkey display works again. Should have been power management services only, strange... I also reinstalled the hotkey display function, but this didn't seem to have any effect.
Anyway, now I hope the display won't suddenly turn dark again. Or at least that it will suddenly turn bright again after that.