Mi 4 Replacement Screen, Bottom Flex Cable

Discussion in 'Xiaomi Mi 4' started by v3nom, Jun 22, 2015.

  1. v3nom

    v3nomMembers

    May 28, 2015
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    I recently replaced screen on my MI4 and everything is working well except the lighting on capacitive buttons. Firstly, menu button was lighting weaker and now it doesn't work at all on all 3 buttons. Button light option is enabled in settings. I have read somewhere that it is controlled by bottom flex cable which I also had replaced because during the lcd change they accidentaly cut the flex cable in service. Also, reception is not the best now and as I see from the pictures it is attached to the same flex. Searching the internet, i found 2 types of flex cables, one which has written LTE-TD on it and another one which has writtens something starting with W. I have MI 4LTE-CU, atleast that is written in settings under model number. Would changing the flex cable again solve my problems and if so which one should I get?
     
  2. Acid

    AcidScripting Ninja
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    Aug 20, 2011
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    Of course. Buttons lighting and antenna are connected to this part.
    Replace with TD LTE part and it will be ok.

    Wysłane z MI Note Pro
     
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  3. v3nom

    v3nomMembers

    May 28, 2015
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    Thanks, I will try and report back.

    Sent from my MI 4LTE using Tapatalk
     
  4. v3nom

    v3nomMembers

    May 28, 2015
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    Ok, I was in service and they didn't replace flex cable but soldered the connector (?) as the problem was there and now it works as it worked before - back and home button light normally but menu button has weaker backlight. Would changing the flex solve that or is that screen related?
     
  5. Acid

    AcidScripting Ninja
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    No. Backlight level is distributed by that white cover above led diode. If the cover is black or bad quality then buttons are backlighted not equal. Also check led because MI4 has actually 2 leds here. If one is bad or not soldered then you get the same effect.

    Wysłane z MI Note Pro
     
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  6. v3nom

    v3nomMembers

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    I'll check it. By "white part" you mean touchscreen part under the screen? If I'm right leds are not on flex? Do you have picture maybe? Thank you very much.

    Sent from my MI 4LTE using Tapatalk
     
  7. Acid

    AcidScripting Ninja
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    Yes button leds are on flex part in the middle (two white leds). They power touchscreen buttons with light. That light is distributed by a white reflexive plastic part inside bottom touchscreen size. If it's poor quality then the light can't be distributed equally, thus light from buttons are worse than original part.

    Wysłane z MI Note Pro
     
  8. v3nom

    v3nomMembers

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    Leds look ok, it's probably part of screen then and I bought "genuine" one. In total dark it looks ok but it is noticeable that menu button has weaker lighting but it. I also have some light bleeding on the sides of the screen between the frame and screen and I suppose because there is tape which glued screen to the frame, should there be a tape anyway? I saw now that there is double sided adhesive patch which, I suppose, glues screen to the frame and I'm not sure I got that with the screen so should I buy that and remove the tape on the sides?
     
  9. Acid

    AcidScripting Ninja
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    LCD screen is glued to frame with stickers, so no tape involved.
    If a service replaced your lcd with tape then... well you should look for better "service" next time.

    Wysłane z MI Note Pro
     
  10. v3nom

    v3nomMembers

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    They never had Xiaomi phone in service. If I knew then what I learned through this whole process I would've done it myself. Thanks Acid.

    Sent from my MI 4LTE using Tapatalk
     
  11. v3nom

    v3nomMembers

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    Ok, I got the sticker now but they told me there is a good chance to break the lcd if I remove it. So is there any way to remove the screen and not break it?
     
  12. Acid

    AcidScripting Ninja
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    You mean remove broken screen? Of course. Just use hairdryer about 8 minutes to the screen and after that you will be able to unglue lcd from frame. Of course do it very delicate and use sucker to take off the screen.

    Wysłane z MI Note Pro
     
  13. v3nom

    v3nomMembers

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    It's not broken, I just want to put it with proper sticker and to remove the sticky tapes from the frame. I don't want to break it, that's why I ask.

    Sent from my MI 4LTE using Tapatalk
     
  14. Acid

    AcidScripting Ninja
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    Removing glass is always risky because normally you do it when it's broken. Now well you have to heat it much to melt the glue. Then use sucker to take off the screen.

    Wysłane z MI Note Pro
     
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  15. silas guo

    silas guoMembers

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    http://dragon-tt.com/Videoxx.aspx?id=1005
    This video will guide you to separate LCD screen assembly and frame.
    But it is a risk to operate this.
    LCD screen and touch screen assembly with front housing is better choice for for many mi fans.
    Wisd you can succeed!
     

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