Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

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?


share|improve this question

Best way is contact Lenovo Support or apply warranty for your ThinkPad.

Because it's look like HW problem.

share|improve this answer
OK, thanks for the help! – srunni Feb 3 '10 at 21:40

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.