I have bought a generic touchscreen replacement (not the actual screen where pixels are drawn, but rather the touch sensor where touches are captured) for my Defy/MB525, and replaced it myself.

It doesn't work, it seems to register many random touches in a few seconds (while the charger is disconnected, and no screen protection films are present). I know I probably either did something wrong or got a malfunctioning touchscreen, but maybe I'm missing something?

Do I need to perform some calibration? If so, how can I proceed? My phone is asking for a locking code and I can't enter it as it is.

  • Depends on driver for touch sensor used in conjunction with touch screen used.Usually a small flat file detailing the calibration is stored in /system/etc, it all really depends. :)
    – t0mm13b
    Jul 11, 2013 at 17:12

5 Answers 5


As you asked for a calibration tool: The Playstore seems to have some suitable candidates, e.g. Touch sensitivity calibration. But while this might be helpful, the permissions look quite suspect: The only job of the app is screen calibration, but it requests permissions such as accessing your contacts, call phone numbers, read and send SMS/MMS, and more -- according to a screenshot on the apps page at Google Play. Funnily, the permissions tab says differently: No permissions required... So I'd give it a try, and abort installation in case those permissions really turn up.

  • What do you mean by " in case those permissions really turn up"? If I install an app from Play, I'm granting the permissions on installing it, and therefore, the app won't explicitly request the permissions because it already has it... Right? Sep 10, 2013 at 20:59
  • 1
    On installation, you will be presented with a list of permissions the app requests. If it says there "this app requires no permissions", everything is very fine. If it lists permissions requested, check them carefully for those I've mentioned above, as they are not related to the purpose. When in doubt, check comments, ask the dev to explain. I don't know neither app nor dev, so I cannot say "just go ahead" while keeping a good conscience :)
    – Izzy
    Sep 15, 2013 at 10:48

Its not the malfunctioning in the screen but when you disconnected your screen, phones default values/drivers got messed up and are unable to find the new or the old screen driver you connect.

visit XDA forum thread you can fine more info on that.

BTW is it happening when you connect charger?


Are you having any screen guards in the new screen ? Because low cost screen guards also can cause this. I had the similar issue in my Nexus 7 after applying the new screen guard.

Also other possibilities are like user2541963 mentioned , if you are having a charger that is overcharging the phone , while charging the phone wont respond.

  • What's a screen guard? Those films that will protect from dust, grease, etc? I don't have any. And the issue happens when there's no charger. Jul 10, 2013 at 15:44

If you have the touchscreen gestures in the Accessibility part of your Settings on, you might be experiencing this problem. Disable touchscreen gestures, and I think it should work out fine. Enable them after you don't require them.

P.S.: I had the same problem while playing with Piano Tiles.


S Sandeep

  • A touch of screen calibrators should work out very well (eg: SGS touchscreen booster.)
    – Sandy Man
    Dec 8, 2014 at 7:40

I once had similar sounding behaviour when I replaced the screen on my HTC phone. It turned out that I had damaged the very delicate ribbon cable that linked the touch screen to the motherboard.

  • And how did you know that you had damaged the ribbon cable?
    – jackbravo
    May 29, 2015 at 22:42
  • @jackbravo: By replacing it and fixing the problem.
    – RobJ
    Jan 5, 2016 at 14:45

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