09-20-2017 02:48 PM - edited 09-20-2017 03:22 PM
I have a Lenovo X220 Tablet that has touch screen and pen. They suddenly stopped working today. The LCD screen still works pefectly fine, however. The touch screen is enabled on the touch settings. When I try to calibrate, it does not detect my finger or the pen. I also noticed that when I tried to reinstall the driver and it said "a supported tablet was not found on this system".
I have the most recent bios. I am running Windows 7 that came with the laptop. All windows updates completed.
Is it possible for the digitizer to be defective, but the LCD screen to work perfectly fine?
Could it be just a ribbon failure?
Which part would need to be replaced, if this is the case?
Any advice would be appreciated. Thank you.
09-20-2017 03:29 PM
Even though it looks like a single device, it is really 3 separate ones. There is a basic panel. There is a static discharge digitizer in the front to sense finger touches. There is a second Wacom digitizer behind the panel to detect the pen. Any of them can fail. The wires in the cable can also crack. Since both digitizers failed, I would first look in device manager to see if there could be a problem with a USB hub. (digitizers both connect as USB devices.) My next guess would be the cable. Sorry I cannot be more definite.
09-20-2017 03:34 PM - edited 09-20-2017 03:37 PM
Thanks for the reply, Rich.
I noticed a USB exclamation next to an Unknow Device in the device manager, but it seems to be related to the webcam which seems to detect, then lose the connection. I tried replugging in the webcam and it redetects, but soon after the system tray tells me "USB device unrecognized".
The webcam is not listed (not detected) in device manager.
I deleted the touch inputs under human interface devices in device manager and they did not reappear after refreshing.
It is worth noting that the fingerprint sensor works perfectly. So do the speakers and all the lights on the bottom of the LCD bezel.
09-20-2017 03:42 PM - edited 09-20-2017 03:43 PM
I believe the webcam and both digitizers are on one hub and the fingerprint is on another one. Speakers and lights are not USB. I would guess your microphone is alse dead. I would remove the USB hub that is having a problem via device manager and then restart the machine.
09-20-2017 03:51 PM
I imagine you're correct that the microphone is also dead.
I just removed the "unknown device" under USB devices and rebooted as you suggested.
The installation of an "unknown device" failed after windows re-logged in.
Interestingly, the Wacom device that I did not remove initially from the human interface devices list is now gone.
Does it seem more likely that this is a cable issue, and not strictly the LCD touch feature, given that multiple components are affected? (I assume they share the same cable,) If so, which cable?
09-20-2017 04:15 PM
There is a complicated cable that runs through the swivel hinge. It shares that space with the antenna wires. There are 2 legs that go to the motherboard and several inside the lid. The cable does fail occasionally, since it swivels, etc. It might be the hub itself on the motherboard. The signal chips do fail sometimes. I have done several and I can say that changing the cable is not a fun job and would not be an ideal "first repair project". If you do it, take pictures of how the cables are run under the bezel at the bottom.
09-20-2017 04:19 PM
You're definitely correct it is not a fun project to start with - I fortunately did replace the CPU fan about 3 years ago, which required virtually a complete teardown of the machine. But it has been quite a while.
So the two legs that go to the motherboard are actually part of one cable? Do you know the part number I would try to order online (ie: eBay)?
09-20-2017 04:31 PM
Please see this attached photo of the cables that connect to the motherboard from the LCD via the swivel hinge.
On the left is model 50.4KJ02.001. The cable on the right is model 50.4KJ03.002.
Which one of those would the touch screen and webcam be connected through?
09-20-2017 04:34 PM
There is one cable. Either 04W1775 or 04W1776 will work.
CPU fan does not require disassembling the lid. I have taken quite a few tablets apart. I can probably change that fan in 30 minutes. The cable takes me over an hour. Unfortunately, there is no way to know if the cable is the problem until you change it. If your hinge is loose, now is the time to change it.
09-20-2017 04:39 PM
Thanks again for the quick reply.
I took a picture of the cables attached to the motherboard I meant to show you before.
To confirm- the 04W1775/04W1776 will have both of these connectors?