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General Weird touchscreen behaviour after glass repair

Discussion in 'Android Devices' started by rossmcm, Mar 13, 2014.

  1. rossmcm

    rossmcm Newbie
    Thread Starter

    My S4 bit the pavement and as the display and digitiser still seemed OK I opted for a cheaper repair and just had the glass replaced by a local guy.

    He was happy to report that the digitiser did indeed seem OK and returned my phone with only a new glass fitted.

    A couple of days later this appeared:


    It looked like water between the glass and display and behaved like it - i.e. the size and shape varied with application of (gentle!) pressure. I waited for a few days and even tried some gentle warming of the phone to try to accelerate the drying. Nothing worked so it was back to the repairer. He took it to bits again and cleaned and dried the glass.

    All is well now, except for a curious problem. Occasionally the phone will become completely unresponsive to touch. I found however that I could recover it from this state by wiping the phone screen-down on a fabric surface -such as my trouser leg.

    After turning on debug mode and enabling the options to show the touch point on the screen as a white dot, and show the swipe path, it was more obvious as to why the phone was becoming unresponsive.


    (Note that the spot and cross-hairs aren't part of the fault - they are a result of the phone having the screen debug options enabled).
    This tells me that when this problem occurs, it is because the digitiser thinks the screen was being touched continuously almost dead-centre in the middle of the glass - i.e. the debug mode white dot is visible in the centre of the screen all the time. Normal wiping and swiping is ineffectual because the phone thinks that a finger was pressing on the screen. One way out of this mode seems to be to "wipe" the spot to the screen edge, which I could do by wiping it face down on my trouser leg. I also discovered that turning the screen off and then on again kicked it out of this mode. I can also make the spot disappear (i.e.lift the phantom finger off the glass) by covering the front camera with a finger, or a business card (or maybe its the light sensor - it's hard to tell). If I uncover the camera again the spot returns. Go figure that one. And yes, I have turned off all the fancy face recognition, air gesture wavey things.

    This problem often happens when the phone is in a soft-covered spectacles case I keep it in. I pull the phone out to use it and discover that it hasn't been asleep, and it's really warm through having been in it's pouch with the display running.

    I'm curious about both of these things - the moisture (it was a very humid day when the first repair was done), and the phantom finger press. The display sensitivity and appearance otherwise is 100%.

    Any learned comment is appreciated.



  2. trucky

    trucky Android Enthusiast

    I think local guy needs to correct the issues. The bond between digitizer and actual screen is one of the more tricky repairs and it seems rare to hear someone successfully doing it without resorting to the full digitizer replacement. I'm not saying it can't be done, but many report issues similar to yours and they often seem to crop up after things all look ok initially.
  3. Fehrmann

    Fehrmann Lurker

    Hi. I did loads of s3 glass fix with loca uv glue. All works fine. Sounds like he did the fix only with sticker tape on top and edges (as in no loca layer) or he did loca but failed to give enough uv light to make loca bond properly. If loca does not get adequate uv light it will remain in its liquide state or only partly hardned. If its completely hard it will not behave strange. Test screen with z device test or android sensor. Some only do the repair with no loca. Its crap. If you press hard on the glass with no loca, the phone freezes and you have to reboot all the time. The loca prevents this also . Good luck.

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