Thinkpads Forum

Can someone tell me where the switch is that senses the screen being closed? I found posts that indicate it is magnetic, but where is it and how does it work?

Thanks

it's probably in the hinges and once the LCD reaches a certain angle it closes a circuit which sends the signals to sleep or shutdown or whatever.

Why? Just curious though as to why you asked

I have a machine that acts like the lid is closed.

The switch is on the inverter board at the bottom of the screen assem. Just get an old magnet and wave it near the base of the screen and the machine will enter suspend and resume.

thanks

You can also place a small,thin strip of aluminum foil (approx. same or slightly lesser thickness as the lower part of screen bezel and place it (or tape it carefully) in on the base towards the back edge where the hinges are present. This should stop the magnetic switch activating ... if that is what you want.

Do be careful about the foild, don't let it extend in the LCD area to avoid sctatches.

Not to be argumentative for the sake of it, but the magnet idea and the foil idea probably won't work. The machine is acting like the lid is closed when in fact it is open. In order for it to do that, the magnet switch on the inverter would have to be made, and possibly made permanently or stuck. If you close the screen one would assume that there is a magnet in the keyboard bezel area that makes the switch. So you see, since the machine thinks the lid is closed, the switch is already made and waving a magnet in front of it might not do anything. Secondly, if the switch is already made, putting a piece of aluminum foil over it is not going to help either, because it is already made when it is not supposed to be. What would you be preventing it from doing? I'd try to remove the LCD bezel and inspect the switch itself, but knowing Richk he's probably already on it. Could be the magnet is missing or out of adjustment under the keyboard bezel as well

It turns out that I "cooked" the inverter.

I have a similar problem on a T60. I swapped an inverter out of a good working machine into another to see if it had a bad inverter. Well, that didn't work so I swapped it back. Guess what, the original inverter in the donor machine now would not light the backlight. So, I figured I must have a bad inverter. I ordered another. Put it in, same problem, the backlight will not light. I am losing my mind on this bug. Any ideas?

That's downright scary. I passed a drive magnet along the bottom of the screen frame between the hinges, and about midway there it went "snick" and the screen went black. AND STAYED BLACK, it wouldn't come back on, even with another magnet pass. My machine didn't suspend or sleep--just the screen went black.

Either there's more than a simple switch involved, or there's something "sequential" set up with it.

Well, in my case I know the lid switch is working because the machine goes into stand-by when I close the lid. I can tell what it's doing because I have an external LCD hooked up to the Thinkpad. So, for whatever reason I can't get a new inverter to light up a known good working LCD.