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Fixing the ghost touch/grounding issue once and for all! (Hint: it was never a software problem)

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  1. vantt1 Jelly Bean Nov 23, 2014

    vantt1, Nov 23, 2014 :
    Disclaimer: do not try this at home, I guess

    Updated 11/25/14 7:00pm PST, 10:00pm EST, 3:00am GMT (did I do it right?): a follow-up!

    Ever since I got the OnePlus One, I've been having issues with the touchscreen. Some touches weren't being registered, and sometimes when I'm scrolling, something along the way would be touched instead. Double taps turned into single taps, the camera shutter button was hard to touch, and typing was unpredictable. The list goes on. I never documented it because it just happens without warning, so I complained about it on the forums instead. See the follow-up thread to get an idea of the problems I was having.

    OnePlus has addressed this issue as a "software bug" (just like the yellow tint), and promised to fix it in future updates. It worked for some, and I did notice some improvement, but it just wasn't good enough for me. I thought all the software did was merely filter or mask the effects of the grounding issue, and anticipated or extrapolated touches made by the user.

    No matter which ROM or which version of CM11S I used, the touchscreen was never quite perfect. At some point, I knew for sure it wasn't simply a "software bug", because I've tried numerous kernels and ROMs, to no avail.

    So, I went on a little investigation, because I'm actually quite familiar with problems like this. The iPad Mini suffers from a very similar grounding issue when the digitzer gets replaced. The original digitizers are all insulated properly from the factory, but when it breaks and needs to be replaced, the replacement screens don't come with the insulating tape pre-installed. If not insulated, the digitizer makes contact with the inside of the aluminum unibody, and thus creates the grounding issue.

    The tape insulating the touchscreen circuits has to be moved over from the original, broken screen to the new screen in order to prevent the issue. See the original, broken iPad Mini digitizer (left, bottom) compared to a new, replacement digitizer (left, top):
    [​IMG]

    Note how there are areas of the iPad's chassis that can make contact with the digitizer if not isolated.

    I was 90% sure that something similar was going on with the OnePlus One. And I was right.

    I fully disassembled my OnePlus One (for the second time), but this time around, I removed the screen as well. I didn't do it the first time because it's a risky operation; I might damage the only screen I had during the process, and it won't be as secure of a bond as before. But YOLO, right?

    [​IMG]

    Here are the instructions on how to do it yourself! (In theory)

    As suspected, the digitizer flex makes direct contact to the metallic chassis before being connected to the logic board, just like the iPad Mini does with a replacement screen.

    [​IMG]

    And sure enough, when the flex is isolated from the chassis, the problem disappeared. The phone had no problem registering all 10 touches, and every touch was more responsive than ever.

    [​IMG]
    Debug mode, hardware edition!

    [​IMG]

    So the fix was quite obvious; insulate that digitizer flex! I cut some of the insulating tape from the iPad Mini's digitizer and stuck it on the chassis where it was touching the flex. Any thin tape will do though.

    [​IMG]

    I then reassembled the One, and as expected, the touchscreen now works perfectly. No more ghost touches, and no more grounding issue. I'm as happy as Larry :D

    [​IMG]

    Why, then, did some units suffer more than others, and some received perfectly fine units? Well, here's my hypothesis. Unlike mainstream smartphone manufacturers, who either use properly isolated digitizers and/or double-sided 3M tape, OnePlus neglected the former and used glue instead.

    Look closely in the image below - you can clearly see that it isn't tape that's holding the screen in place. That pattern is characteristic of unset glue that's been compressed. (click to zoom)
    [​IMG]

    It loses form and stickiness when removed. Double-sided tape retains its shape and doesn't lose stickiness.
    [​IMG]
    [​IMG]

    Because glue was used, every individual phone most likely had a different clearance between the chassis and the digitizer flex.

    From what I heard, the newer units have fixed this problem, but I can't confirm for myself exactly how they fixed it.

    So there you have it! As it turns out, it really was a hardware problem (judging from my investigation). It would be great if other forum members can confirm my theory if they have the chance. If you:
    1. Have a One that suffered from this issue
    2. Have a broken screen
    3. Want to try your hand at replacing the screen yourself
    Now's a great opportunity! (At your own risk, of course)
     
    Last edited: Nov 25, 2014

    #1
  2. Hanson Lee Lollipop Community Expert Nov 23, 2014


    #2
  3. Reivon Choccoli Jelly Bean Moderator Nov 23, 2014


    #3
    JHong, Quincy_Ng, Peter8169 and 12 others like this.
  4. reyscott1968 Jelly Bean Nov 23, 2014


    #4
  5. ChrisTerp KitKat Nov 23, 2014

    ChrisTerp, Nov 23, 2014 :
    Great work and tinkering. Nice to see someone looking out for us in the forum with these breakdowns and analysis. Thanks.
     

    #5
    Mikewilzn, AndreaComi, Bakr and 3 others like this.
  6. Kenneth Lopez Gingerbread Nov 23, 2014


    #6
  7. Waterdroid KitKat Community Expert Nov 23, 2014

    Waterdroid, Nov 23, 2014 :
    If this really is the problem, what on earth does OnePlus mean when they say they'll fix it in 'the next update'?
     

    #7
  8. vantt1 Jelly Bean Nov 23, 2014

    vantt1, Nov 23, 2014 :
    Leave its users hanging onto broken promises.

    Jokes, it seems to me that the software updates include optimizations to try and counter the ghost touches. I noticed that scrolling in 38R was slower than it was in 33R, maybe because the software was interpreting the touches in a different way.
     

    #8
  9. Sticky stanly Honeycomb Nov 23, 2014

    Sticky stanly, Nov 23, 2014 :
    I dont have the ghost touch but im going to follow this just in case a friend of mine gets one that has this issue. Cudos :D
     

    #9
    ronoldo likes this.
  10. carbine30 Lollipop Nov 23, 2014

    carbine30, Nov 23, 2014 :
    A morphine injection too cool down the customers.
     

    #10
  11. darreal Froyo Nov 23, 2014

    darreal, Nov 23, 2014 :
    So now that your proofed that it's a hardware problem and not a software problem like the Oneplus 'support' (HAHAHA) says, everybody can fill in a RMA?
    It's a hardware problem so you have warranty no?

    What a lack of professionalism,
    Opo : 'it's just a software problem' ..
    Random guys that use phone for a hobby, or something, solve the hardware problem..

    Just another OPO logic...
     

    #11
  12. bestlands KitKat Nov 23, 2014

    bestlands, Nov 23, 2014 :
    Or I can sent my phone to you for you to fix. Also I'm having battery problems.
     

    #12
  13. Maxoris Gingerbread Nov 23, 2014


    #13
    goldybhowmik and Junglefest like this.
  14. Pjayk Gingerbread Nov 23, 2014

    Pjayk, Nov 23, 2014 :
    In family/close friends (5 opos total) none had this problem but you have my like and respect for that "search and found" problem!
    OnePlus could just make a statement confirming what you find out because we all know there is a lot of people with the same problem.
    Cheers mate, and congrats by your "new and fullfilled" Opo
     

    #14
  15. vantt1 Jelly Bean Nov 23, 2014

    vantt1, Nov 23, 2014 :
    I think the thing was that this kind of problem wasn't severe enough for most people to go through the RMA process and be without a OnePlus One for a month, that's why the software bug thing kinda worked.
     

    #15
    9koros, najmulhaq, ramli7 and 4 others like this.
  16. leemartin KitKat Nov 23, 2014


    #16
    ZiggyG3 and ronoldo like this.
  17. Joyyy Jelly Bean Nov 23, 2014

    Joyyy, Nov 23, 2014 :
    Nice one @vantt1 !
    Will do this soon great discovery :D
     

    #17
  18. ibrahimnadir1 Honeycomb Nov 23, 2014

    ibrahimnadir1, Nov 23, 2014 :
    I'm very upset with such an issue and i would really appreciate if OPO would fix it for themselves. This is going to loose a lot of customers for them! Sadly, i'm one of them and returning my phone. I donno whether i should return or replace it!
     

    #18
  19. Transparant KitKat Nov 23, 2014

    Transparant, Nov 23, 2014 :
    For me it is a software problem... In 25r until 33r I never had any issues with Ghost Touches etc, they started in 38r.
    So on my side it does seem to be a software issue.
     

    #19
  20. ibrahimnadir1 Honeycomb Nov 23, 2014


    #20