11-13-2008 02:08 PM - edited 11-13-2008 02:10 PM
I have a T400 LED (Part number: NM52LAT) with Windows Vista Business SP1. I have the problem that sometimes I can't adjust screen brightness. Neither via the Fn-Keys nor via the power manager. A reboot fixes the problem (as usually with Windows related software, I guess *g*)
It seems to me as if this problem occures mostly after waking up from stand-by or hibernate. I can't really say that the problem is reproducible, 'cause it doesn't happen every time coming up from stand-by/hibernate, but it happened often enough to annoy me.
My system is up to date with the latest updates (ThinkVantage SysUpdate as well as Windows Update). I primarily use the chipset graphics. I deinstalled some Lenovo software packages like "access connection" (didn't work at my university's wlan) or stuff like "lenovo welcome", but drivers and important (in my opinion) software is still installed.
I hope someone can tell me it's just a driver problem and will be fixed soon.
05-08-2009 05:26 PM
Try reviewing again your Power Manger settings. For my situations, I have disabled all the dynamic brightness controls settings in the global tab.
Does this occur when on both battery and when plugged in?
I use Power Source Optimized battery plan and have initial settings applied to my preferences.
Does your On-Screen Display (the green bars) show up when attempting changes via Fn+Home/End?
Best of fortune!
Thinkpad T400-2764CTO | Penryn T9400@2.53GHz | 4 GB RAM | ATI HD3400 + Intel GM45 | 160GB 7k200 | 14.1" LED WXGA+ | Vista Ultimate SP1
06-03-2009 11:39 AM
I have the same problem. To answer your questions, Ulu:
I have all my dynamic brightness controls settings disabled, but the same problem persists.
It occurs both on battery and when plugged in.
I use Energy Star plan.
And, no, the green bars don't show up.
Is there a way to restart the brightness control windows service, at least? It's a pain to reboot every time.
06-06-2009 04:11 AM
i have seen many people complain about the bug. The bug occurs on my T400 as well.
simplest fix i can offer is to close and re-open the screen. that works for me, the controls are re-enabled after that. Am running windows vista Sp1 with all updates prior to SP2.
07-27-2009 06:36 PM
Bump for Lenovo to take a look into this.
It's happening for me too, on a brand new T400. Solution of closing and opening the screen seems to work. I suspect a driver issue...partly worsened by the occasional blue screen...I've had 3 since I had the machine... Hopefully Windows 7 is better...
hopefully they'll fix it...
This thread has more details...
Cheers to all for sharing!
07-28-2009 12:16 PM - edited 07-28-2009 12:18 PM
Had same problem on T400 model number 2765-51G
I reinstalled Power manager and display driver. Problem solved for me
08-03-2009 04:52 AM - edited 08-03-2009 04:55 AM
Same problem here, XP SP2
I use Dynamic Brightness Control, and asks to decrease on all settings.
Some times it stays low after login, ignores FN for brightness control
Some times it stays low, accepts FN for brightness control
Some times it just works perfect