Touch screen problem after switching LCD

[Longlife]

Hi,

a while ago, I cracked my Uni's LCD. So I ordered a new one including the digitizer, opened my Uni and swithched the displays. Now at times, the touch screen wouldn't work at all - unless I tap the upper left corner (the start button; in portrait mode) or the lower left corner (the left button or slightly above it; in landscape). After that, tapping everywhere works normally. Does anyone have an idea what this could be caused by or how to solve it?

Thanks in advance!

[-Jonny-]

I'd make sure your contacts are very clean. If you think maybe they're not, then take out and clean contacts with dry cloth or contact cleaner and re-insert.

Also, make sure there's no debris around screen. That nothing is pressing on digitiser anywhere else that gives false postive for it.

enigma may be able to help you better, I think she's more accustomed to the HW

[enigma1nz]

Generally, all touch problems are associated with a digitizer. Without actually seeing your device I assume your digitizer is faulty and the problem may be either improper adhesion or the soldering joint improperly formed. Adhesion problem may be resolved by warming the screen with a blowdryer, no need to get it hot, just slightly warm all over and smooth with a soft cloth as if you are applying a screen protector, it loosens the special sticky gel that attaches the digitizer to the LCD and usually helps in cases where sensitivity is sporadic or screen calibration returns wrong response. Check for any bubbling, although not seen when the screen is viewed directly, some may be noted at the angle.
However, in your case there are certain points that need to be pressed in order for it to work, so I take it, the screen works most of the time and the problem is intermittent, the corners that need to be pressed might be the ones where adhesion is not up to scratch.
Try re-assembly, if all fails - contact the screen supplier, faults can happen, especially in non-OEM parts.

[enigma1nz]

Do keep us updated if you find the solution, I am sure all members can benefit.

[Longlife]

Well over time, the situation changed so that the touch screen didn't work at all, unless I was pressing one spot above the LCD fairly hardly, at which time it worked without problems. Once I stopped presing the spot, it stopped working again.
So I tried opening the Uni and disconnecting and reconnecting the LCD FPC (which was located just under the spot that needed to be pressed), which seems to have solved the problem :)