Sporadically Flashing Brightness Bar on T61

[ArtShapiro]

I posted a few weeks ago about my T61 (6460-7EU) which had suddenly gone stone dead while in use. Lenovo rejected the warranty claim due to alleged water damage, and upon posting some photos here there seemed to be a consensus that this was, in fact, true.

The unit had its planar (why can't "they" just say motherboard?!) replaced by Brad Borax, forum member "Brad", and he did excellent work at an unbelievably modest price.

I almost never run my laptops off battery, but was forced to do so on Saturday at a coffee shop with no outlets. (The legendary Martin Diedrich, familiar to coffee aficionados, wants his shops to be refuges from the pressures of the business world; he doesn't realize that some of us use the laptop for fun - in my case the New York Times crossword puzzle.)

To my surprise, every minute or two, the brightness bar at the bottom of the screen would come up for a few seconds and disappear. I certainly wasn't invoking the hotkey combination to change the brightness. Deliberately changing it one time, upping it by one bar, didn't affect the subsequent behavior.

Needless to say, this was rather annoying. Does anyone have some insight as to how this behavior could be analyzed? I don't even know if I have a strange issue with the new planar or if there's some sort of Windows XP problem here.

Art

[EOMtp]

I don't even know if I have a strange issue with the new planar or if there's some sort of Windows XP problem here.

The problem is not with Windows XP. The brightness control is hardware control through the BIOS, totally transparent to Windows XP and outside of its control domain.

Replacing the keyboard would be my first step in isolating the cause of the problem. If you don't have a second T61 keyboard, then disconnect the Thinkpad's keyboard and test with an external USB keyboard. If the problem disappears when you disconnect the Thinkpad's keyboard, then you found the culprit.

[ArtShapiro]

Replacing the keyboard would be my first step in isolating the cause of the problem. If you don't have a second T61 keyboard, then disconnect the Thinkpad's keyboard and test with an external USB keyboard.

I didn't have another T61 KB, so I tried an external USB, unplugging the laptop's keyboard after using it for the power button.

Alas, the problem didn't disappear.

Interestingly, I think it only happens when I'm typing, as nothing bad seemed to happen when I just sat looking at the screen waiting for the unexpected display. As long as I was idly using the keyboard, it would happen every minute or two.

Any other wild ideas out there?

Art