ThinkPad X200 Tablet lid closing detection mechanism and no backlighting

[alfonsojr1993]

Hi Everyone!

My ThinkPad X200 tablet (non-touch, pen only) recently had an issue with the pen input. It would work for a few minutes and then suddenly no longer work. This usually happens when I flip it to tablet mode, but would randomly happen at other times as well. I suspected an issue with the wiring so I ordered a new LCD cable.

I installed the new cable and hooked everything up correctly, but I've run into other issues. There's no longer any backlighting and I'm suspecting the inverter may have gone out. However, I then realized that when I close my computer, it doesn't go to sleep like it usually does. The lights on the lid (not the ones inside below the display) are also not lighting up. I can see my desktop on the display with the aid of a flashlight and I've also confirmed that the pen input is working!

Because I'm curious of what's going on, my question is, how is the lid closing detected on my ThinkPad? And if you have any idea of what may be causing the backlighting issue, your input is welcome.

My computer is a ThinkPad X200 Tablet (7449EU) running Windows 10.

Thank you!

[RealBlackStuff]

Welcome to the forum.
Don't know how this is done in the tablet, but the regular X200 has Hall effect switch.
See here: http://forum.thinkpads.com/viewtopic.php?t=102336
or here: http://forum.thinkpads.com/viewtopic.php?t=113552
Your X200t shouldn't be too far off.

[alfonsojr1993]

Thanks for the info!

Apparently the tablet also has a similar Hall effect switch, except with 2 magnets integrated into the bezel, each on opposite sides. I assume it detects whether the computer is actually closed or in tablet mode.

I reinstalled the old wires and lid detection worked as expected, while my new wires didn't do a thing. The status lights on the lid did not light up with the new wires but did so with the old ones. So apparently I've acquired some faulty wires and I'll be getting a replacement soon.

As for the backlighting, no backlighting was observed with the new or old wires, so I'm assuming that the inverter is dead. I'll be replacing that as well.

[RealBlackStuff]

You could also have blown the backlight fuse...

[alfonsojr1993]

Do you know where the fuse could be located?