ThinkPad T400 backlight doesn't always turn on when booting from battery

Posted by srunni on Super User See other posts from Super User or by srunni
Published on 2010-02-03T05:28:01Z Indexed on 2010/05/04 4:58 UTC
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thinkpad

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battery

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bootup

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led

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backlight

I have a Lenovo ThinkPad T400, which I've owned for about a year. A while back, I noticed a problem in which the LED backlight would not always turn on when booting from battery. Usually, if I hold the power button down until the BIOS screen shows up, the backlight turns, but sometimes even that doesn't work. If I just press the power button and let it go right away, the backlight usually doesn't turn on.

This happens before the OS (I dual-boot Linux and Windows) gets a chance to boot - the BIOS screen itself is displayed without the backlight if it fails to turn on, so the problem isn't at the OS level.

Any ideas?

Thanks!

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