Screen Brightness Dims while On Battery

[nikki605]

So I've had my T410 for a couple months. I've noticed one annoying problem. I start with a fully charged battery and disconnect from the a/c charger. The brightness goes to 10 as set in the power settings. So far, so good.

So I'm using it on battery surfing this forum (just an example). The battery indicator says there is still over 3 hours. Then, the brightness slooowly begins to dim. The brightness indicator still says 10, but the screen is dimmer. It stays that way for about 30-60 seconds (I can still read the screen during this time) and then the brightness slooowly comes back up to where it was. The brightness controll still says 10.

It typically won't do it again for the rest of the time I am on batteries. Eventually, I'll plug it back into the a/c adapter. I've not seen it happen while connected to a/c.

Anybody seen this before? Any ideas?

[Colonel O'Neill]

Does the apparent brightness change with the content on-screen? The Intel graphics adapter has a power-saving mode that does that. Things also tend to look a bit washed out.

[nikki605]

I would have to pay more attention to the screen content to be able to answer your question with any certainty, but initially, I would have to say, no.

I have not changed the power settings since I got the TP - it is set to "ThinkPad Default."

This change in brightness looks different than when I use the keyboard to intentionally change the brightness. With the keyboard (the brightness starts out at 10), pressing either the up or down brightness control keys changes the brightness in what I'll call "steps."

When the problem occurs that I described in my initial post, I may be either just using the TrackPoint or Touch Pad navigating in a Window, or perhaps typing a post in a forum like this one. The change is slow, gradual and smooth as it goes dimmer and then stops at some point. It looks like slowly turning a dimmer rheostat connected to a lamp in your house. Then, after about 30-60 seconds, again in a slow, gradual and smooth manner, the brightness comes back up to where it was. The change is not in the "stepping" fashion like it is when intentionally changing the brightness with the keyboard.

I can continue using the TP on battery for several more hours and it won't happen again.

[nikki605]

I found this topic over on the lenovo forum: http://forums.lenovo.com/t5/T400-T500-a ... d-p/212150

Judging by the dates of some of the posts, this problem has been around for awhile. After reading some of the other descriptions, I would have to change my original description to more like fading or reduced contrast making some print blend into the background color making it almost impossible to read. The actual 'brightness' probably stays about the same. Whatever is displayed becomes washed out.

Driving me nuts

[Colonel O'Neill]

How about you try this?

http://forum.thinkpads.com/viewtopic.php?f=45&t=85986

EDIT: Oops wrong link

[nikki605]

Yeah, I checked that after getting a reply to my topic on the lenovo forum that I posted above. 'Display Power Saving Technology' was already unchecked.

Under Power/Power Plans/Graphics Power Plan Settings/On Battery, I did change it from 'Balance' to 'Maximum Performance.' I will have to use it on battery for awhile to see if the change had any effect.

[Colonel O'Neill]

It should've looked something like that:

http://www.istartedsomething.com/wp-con ... saving.jpg

[nikki605]

Yes, it did. Mine was already all the way to the left - Maximum Quality

So far, changing the Intel Graphics Power Plan/On Battery to Maximum Performance, seems to be working. I'll have to use the TP on batteries a few more times to be certain, but I think I'm good.

It was so annoying. I would be typing a forum post like this (just one example) and it was like someone turning down a dimmer switch. I would continue typing, straining my eyes to read, and maybe 30-60 seconds later 'the dimmer switch' would turn back up to where it was. The battery meter said I still had 2-3 hours, so I knew it wasn't running low.

I just wish Intel/lenovo would fix their video driver.

[Colonel O'Neill]

I don't think it's the driver that's at fault, but rather the default settings; changing this setting fixes it and for me, doesn't incur any significant battery life loss.

As a side note: Holy the new interface is different: http://i54.tinypic.com/2604mkh.jpg

[nikki605]

So far, so good with the changed settings.

That's the same interface screen I have, as well.

EDIT: Oh, wait... that IS my pic.

[nikki605]

Old topic, I know, but it looks like lenovo may have finally fixed this problem on x64 systems:

CHANGES IN THIS RELEASE
Version 8.15.10.2253

[Important updates]
Nothing.

[New functions or enhancements]
Nothing.

[Problem fixes]
- Fixed an issue where the screen's contrast ratio might randomly change when
powered by the battery.


http://www-307.ibm.com/pc/support/site. ... MIGR-74433