Touch doesn't work after disassembly - G4 Q&A, Help & Troubleshooting

Hello,
Today I disassembled my LG G4 to change the camera. I followed tutorials online and this is the second time I'm repairing this phone.
Previously I've repaired two other phones.
I disconnected all connectors (back and front cameras, display) removed the motherboard from the frame and put the new camera in.
After that I put the motherboard back and connected the things back. The device booted up fine but sadly the touch on the screen wasn't working.
Display worked fine, using a mouse and keyboard I even tested the new camera.
I disassembled and reassembled the device a few more times. The screen connector has no visible damage however the touch is not working no matter what.
I tried starting it without cameras connected, no change.
Any ideas? Am I missing something?

pepo930 said:
Hello,
Today I disassembled my LG G4 to change the camera. I followed tutorials online and this is the second time I'm repairing this phone.
Previously I've repaired two other phones.
I disconnected all connectors (back and front cameras, display) removed the motherboard from the frame and put the new camera in.
After that I put the motherboard back and connected the things back. The device booted up fine but sadly the touch on the screen wasn't working.
Display worked fine, using a mouse and keyboard I even tested the new camera.
I disassembled and reassembled the device a few more times. The screen connector has no visible damage however the touch is not working no matter what.
I tried starting it without cameras connected, no change.
Any ideas? Am I missing something?
Click to expand...
Click to collapse
You can try cleaning all the internal connectors with 90% Isopropyl Alcohol but if that doesn't work and you're sure that all connectors are clean & solidly connected, you may have to replace the Touch Screen Digitizer (with frame) in order to solve.
Replacements aren't that expensive - google it for local supply or check out: https://www.aliexpress.com/item/For...lgo_pvid=2fd011e4-25cc-4cd1-a57f-b7878b272ca7

Thing is I don't know if the problem is motherboard connector or screen ribbon.

Related

Touch still unresponsive after digitizer replaced

About 2 weeks ago my touch function stopped responding. I was away from the night and it died shortly after and I did not have my charger. The next day once I got it charged up, I powered it on and was able to get a few minutes of working touch sense... then the touch died completely. I opened it up to make sure all of the cables were intact- Everything inside looked perfect except for the little latch that holds down on the digitizer cable was broken off, but that was already like that for a while and everything was still working.) After some fiddleing and no luck, I decided I probably just need to get a new digitizer--- It would be easy to disassemble because my lcd and digitizer were both oem from a drop in the potty a few minths back, which only affected the screen. So today the digitizer came in and I replaced it- NO LUCK! Every once in a while I get a tiny spark of scroll functionality or the bottom of the screen while in landscape mode becomes touchable for a few seconds, but otherwise dead.
Does anyone know what the problem could be since I have already replaced the digitizer???
Right now I am only able too hook up my internet sharing and etc. through MyMobiler.
Thanks

Touchscreen broken after repair!

Hello,
I just got my N7 back from repair where they replaced the ME571K SUB_BD./AS board since the USB Port was not working anymore.
Luckily the port works now, but on the other hand the Touchscreen is not responding at all.
I tried restarting already without success. I also cannot reset the tablet since I got TeamWinRecovery Touch (and CWM 10.2) installed.
I can connect the tablet in bootloader and with "fastboot devices" it shows up as 077a744a.
Could anyone help me on how to flash or reset the tablet?
Ps.: This replacement was out of warranty, therefore I paid for it. The service center suggested replacing the mainboard (to make money) as well. Before I sent the tablet in everything was working just fine except mentioned USB Port.
Natschlaus said:
Hello,
I just got my N7 back from repair where they replaced the ME571K SUB_BD./AS board since the USB Port was not working anymore.
Luckily the port works now, but on the other hand the Touchscreen is not responding at all.
I tried restarting already without success. I also cannot reset the tablet since I got TeamWinRecovery Touch (and CWM 10.2) installed.
I can connect the tablet in bootloader and with "fastboot devices" it shows up as 077a744a.
Could anyone help me on how to flash or reset the tablet?
Ps.: This replacement was out of warranty, therefore I paid for it. The service center suggested replacing the mainboard (to make money) as well. Before I sent the tablet in everything was working just fine except mentioned USB Port.
Click to expand...
Click to collapse
Try flashing the JSS15R factory image.
http://forum.xda-developers.com/showthread.php?p=45671279#post45671279
I just flashed (with wipe) the factory image without success.
There's no response at all. Also when I try to get into recovery mode now the opened Android with the red exclamation mark shows up.
Is there a low level touchscreen calibration or something I could run through fastboot?
Anymore help would be greatly appreciated.
I'm starting to think they just put my motherboard in another tablet with abroken display...
I'd return it, it sounds like total screen failure.
Natschlaus said:
I just flashed (with wipe) the factory image without success.
There's no response at all. Also when I try to get into recovery mode now the opened Android with the red exclamation mark shows up.
Click to expand...
Click to collapse
That fallen android is just an image overlaid over the stock recovery menu. It just means you've booted into stock recovery. You can get the recovery menu by press/hold Power, press/release VolUp, release Power.
Natschlaus said:
Is there a low level touchscreen calibration or something I could run through fastboot?
Click to expand...
Click to collapse
There are various different touchscreen software you can load via fastboot and there is a calibration file in /system/usr/idc, but it isn't clear any of these would help if your screen doesn't work at all.
You can try changing the touchscreen software, worse case, it stays the same:
http://forum.xda-developers.com/showthread.php?t=2428133
Alternatively, you can open up your tablet and check to see if the flex cable for the touchscreen has become dislodged. There are 2 cables that run across the center battery. The one that is reinforced using tape is the one for the touchscreen.
Just did a reset but it didn't work.
I already tried these different firmwares from your link but it didn't make a difference.
I guess the screen is just broken. Or is it possible that the new Subboard is not working with the motherboard and therefore the screen fails?
I opened the back but it looks fine doesn't it? Is the big cable the on for the touchscreen or the orange one?
Natschlaus said:
I opened the back but it looks fine doesn't it? Is the big cable the on for the touchscreen or the orange one?
Click to expand...
Click to collapse
Yes, that is the cable. You can carefully removing the tape reinforcing the motherboard side of the orange cable and seeing if there is anything preventing a good connection, possibly use compressed air to clear out the connection area. The other end of the orange cable also connects to the touchscreen underneath the usb module so you would need to remove some screws to check that connection.
That's about all I can suggest. It didn't sound like a software issue because your screen completely doesn't work.
Yes I will look at the side where I have to open screws since that is the part they changed. Mabybe they didn't connect the screen.
I also wrote the support already.
Thanks for your help, I will report back.
Same problem experienced
Natschlaus said:
Hello,
I just got my N7 back from repair where they replaced the ME571K SUB_BD./AS board since the USB Port was not working anymore.
Luckily the port works now, but on the other hand the Touchscreen is not responding at all.
I tried restarting already without success. I also cannot reset the tablet since I got TeamWinRecovery Touch (and CWM 10.2) installed.
I can connect the tablet in bootloader and with "fastboot devices" it shows up as 077a744a.
Could anyone help me on how to flash or reset the tablet?
Ps.: This replacement was out of warranty, therefore I paid for it. The service center suggested replacing the mainboard (to make money) as well. Before I sent the tablet in everything was working just fine except mentioned USB Port.
Click to expand...
Click to collapse
Hi there
I have also experienced a very similar problem. The charging port on my 2013 Nexus failed to work, I then ordered a replacement part and changed it. It is very straight forward and simple to do for a novice like me.
on replacing the pcb the charging resumed faultlessly but the touchscreen has become unresponsive, i then replaced the old pcb and the screen has resumed functionality, but charging is not working.
The part was replaced by the supplier and it has occurred again, charges fine but the screen is unresponsive. Again i reinstall the old part and hey presto screen is ok.
I am now going to try and replace the actual usb pin itself from the original failed board and see if i can repair myself.
I had also done all the resets and reboots mentioned online.
Not sure if this helps but thought i'd share as its relevant
Many thanks
Is this the n7 2013? If it is how the hell did you get the back off? I tried and was afraid of breaking something.
Sent from my Nexus 7 using xda app-developers app
It's really easy. No tools required. Run your fingernail around the perimeter of the tablet edge between the screen edge and angled plastic. You'll hear the clips releasing as you go. Then carefully work the back off. No glue, just clips. Takes about 1 minute.
Sent from my Nexus 7 using XDA Premium HD app
Any update on how you solved this ?
I would appreciate if anyone could share the solution for unresponsive touch screen, if it's possible at all. The screen only reacts on the edges, and only to the swipe gestures, not to tapping. But all and all is the same - broken USB, replacement part, unresponsive screen.
no_cannabis said:
I would appreciate if anyone could share the solution for unresponsive touch screen, if it's possible at all. The screen only reacts on the edges, and only to the swipe gestures, not to tapping. But all and all is the same - broken USB, replacement part, unresponsive screen.
Click to expand...
Click to collapse
Try this http://forum.xda-developers.com/showthread.php?p=45183659 it made 2 of my tablets usable.
Sent from my DarkKat Nexus 7 using Tapatalk 2
I think this is the same issue: http://forum.xda-developers.com/nex...a/usb-io-pcb-touchscreen-calibration-t2939991
Is there nothing to "calibrate" the screen? Asus is supposed to do it for you.
I think the problem is the rev. number of the usb board.
I found this explicative video on youtube, but I can't put the link. Look for "Nexus 7 2013 2nd gen charge port replacement issue"
I have the opposite problem: I changed lcd and digitizer two times, both times touch screen was completely unresponsive. I wonder if there's a software solution for this. I know usb board have different revisions, but what about digitizers? Are all the same for every nexus 2013 model? In this case I have to think touch screen connectors on usb board are broken somehow...
parcs said:
I think the problem is the rev. number of the usb board.
I found this explicative video on youtube, but I can't put the link. Look for "Nexus 7 2013 2nd gen charge port replacement issue"
I have the opposite problem: I changed lcd and digitizer two times, both times touch screen was completely unresponsive. I wonder if there's a software solution for this. I know usb board have different revisions, but what about digitizers? Are all the same for every nexus 2013 model? In this case I have to think touch screen connectors on usb board are broken somehow...[/QUOTEI
I know this is an old thread, but the problem is replacing a rev 1.3 board with a rev 1.4 board. They are not compatible touch screen wise. I have heard that there is a reset tool that only Asus has that can fix this...
Click to expand...
Click to collapse
My kid broke the original screen and I replaced it with a cheaper one that worked great until he broke it again
Got a new screen but the touch doesn't work and I can't enter twrp except if I disconnect one of the daughther board connector ribbons (can't remember which one now).
My guess is that the screen is for a different revision board.
Any way to solve the problem?
This is the perfect thread. I have a collection of Frankenstein parts and the problem I've had with 5 or 5 devices (flo) is the sub board. Some work, some don't. I'll try the firmware links and report back.
Has any one found solution for this problem, even my Nexus 7 2013 touch screen has stopped working after I repaired the micro USB port. Actually my tablet was not charging and I figured out that there was some lose contact in the micro USB solder joints, untill then my touch working. I haven't changed any daughter USB board but just resoldered the micro USB port after which my charging has started working and I can even connect a mouse or pendrive through USB OTG cable but the touch screen has stopped working.

Damaged touchscreen - can the rest be salvaged?

Hi everyone.
After a sudden heavy rain, I got some water in my Gnex. I tried the old bag of rice trick, only to find out the USB port was not functioning any more, neither for PC connectivity, nor for charging.
Following the advice of a person I no longer consider my friend, I tried spraying some Isoprpyl Alcohol in the USB port. It did get it to work correctly, but it damaged the digitizer, meaning I get random touches on the lower part of the screen (where the Back, Home and Recent apps buttons are).
I took the phone to a service centre where they tried to clean it, but the issue remains. I'll go there today with my wife's phone to see if it's indeed a touchscreen issue or a motherboard issue. I'm not sure if I want to invest in a new screen (over $100 + maybe a new back cover since the current one has quite a few scratches and cracks) and I'm thinking of maybe upgrading to a Nexus 5 or Xperia Z (the latter being waterproof).
The question now would be, could I do something with the hardware? Like, root it, connect it to my wifi and use it as a web server, or connect it to my TV through an MHL adapter and get a "smart TV". Can I get it to ignore touches on the screen completely, and only accept an OTG/bluetooth mouse input?
Any idea is welcome
vladk2k said:
Hi everyone.
After a sudden heavy rain, I got some water in my Gnex. I tried the old bag of rice trick, only to find out the USB port was not functioning any more, neither for PC connectivity, nor for charging.
Following the advice of a person I no longer consider my friend, I tried spraying some Isoprpyl Alcohol in the USB port. It did get it to work correctly, but it damaged the digitizer, meaning I get random touches on the lower part of the screen (where the Back, Home and Recent apps buttons are).
I took the phone to a service centre where they tried to clean it, but the issue remains. I'll go there today with my wife's phone to see if it's indeed a touchscreen issue or a motherboard issue. I'm not sure if I want to invest in a new screen (over $100 + maybe a new back cover since the current one has quite a few scratches and cracks) and I'm thinking of maybe upgrading to a Nexus 5 or Xperia Z (the latter being waterproof).
The question now would be, could I do something with the hardware? Like, root it, connect it to my wifi and use it as a web server, or connect it to my TV through an MHL adapter and get a "smart TV". Can I get it to ignore touches on the screen completely, and only accept an OTG/bluetooth mouse input?
Any idea is welcome
Click to expand...
Click to collapse
One day I got caught in a storm having my Gnex in my pocket. Vacuum and rice tricks didn't work completely, as the phone was working properly besides recognizing the sim card (Mboard issue). What I did was buy a broken screen nexus off of Ebay, and exchanged the screens.
Now I have a fully working mobile phone, plus an MHL connected - XBMC enabled smart TV box, connected with bluetooth mouse/keyboard.
Question: Why would you need to ignore touches on the screen?
As I said, after spraying the USB port with isopropyl alcohol, it appears to have touches all over the bottom part of the screen, as if someone was constantly keeping 3-4 finger and touching away at the soft buttons. Cleaning the phone in a service centre did not help.
vladk2k said:
As I said, after spraying the USB port with isopropyl alcohol, it appears to have touches all over the bottom part of the screen, as if someone was constantly keeping 3-4 finger and touching away at the soft buttons. Cleaning the phone in a service centre did not help.
Click to expand...
Click to collapse
Sorry, I missed that info. Try searching for 'touch blocker' in Google Play. Don't know if that would work on a Gnex though.
Another (hardcore) idea would be to disconnect the screen altogether.

ZenFone 2 stuck in Asus Cover Mode with no haptic feedback after dropping on floor

I'm adding this thread to document my recent findings, in hopes that it may help others recover from similar issues.
I dropped my ZenFone 2 (ZE551ML) on the kitchen floor the other day. When I picked it up, it was stuck in Asus Cover Mode, even though I don't have an Asus Cover. I was unable to get into the phone, so I forced a hard-reboot. After playing with it for a few minutes, I was able to get the home screen, though Cover Mode would intermittently kick on and off every few seconds. I got into the settings and disabled Cover Mode, but I soon realized that I had lost vibrate and haptic feedback functionality.
I took apart the phone to inspect for internal damage, and I noticed a small hairline crack on the flex cable connector that resides on the charger port board (see attached photo for details). The now-broken connector allowed the flex cable to shift laterally from its original position, leading to connectivity issues and causing the problems noted above. I was able to temporarily fix it by disconnecting the flex cable and reconnecting it to its intended position. As a permanent fix, I ordered a new charger port board from a vendor on AliExpress that ran me about $5 USD. I just installed it yesterday, and it seems to work as well as the original.
ospatch said:
I'm adding this thread to document my recent findings, in hopes that it may help others recover from similar issues.
I dropped my ZenFone 2 (ZE551ML) on the kitchen floor the other day. When I picked it up, it was stuck in Asus Cover Mode, even though I don't have an Asus Cover. I was unable to get into the phone, so I forced a hard-reboot. After playing with it for a few minutes, I was able to get the home screen, though Cover Mode would intermittently kick on and off every few seconds. I got into the settings and disabled Cover Mode, but I soon realized that I had lost vibrate and haptic feedback functionality.
I took apart the phone to inspect for internal damage, and I noticed a small hairline crack on the flex cable connector that resides on the charger port board (see attached photo for details). The now-broken connector allowed the flex cable to shift laterally from its original position, leading to connectivity issues and causing the problems noted above. I was able to temporarily fix it by disconnecting the flex cable and reconnecting it to its intended position. As a permanent fix, I ordered a new charger port board from a vendor on AliExpress that ran me about $5 USD. I just installed it yesterday, and it seems to work as well as the original.
Click to expand...
Click to collapse
May I know how you played with your phone to go to the homescreen? I had the same situation but mine is vibrating. I'm just stucked on cover mode.
I hit it against me hands a few times. It seemed to be enough to allow intermittent access to the home screen and settings.
If your device is still under warranty, my recommendation for you is to let Asus repair it. I purchased my ZenFone with a broken screen and repaired it, so I have no warranty coverage. That said, I'd be willing to bet that you can't fix this without taking the phone apart. If I were you, I'd open up the phone, disconnect the battery from the motherboard and the flex cable, antenna, and vibrator from the charge port board, and inspect for damage. If everything looks good, reconnect everything, reassemble it, and try it out.
ospatch said:
I'm adding this thread to document my recent findings, in hopes that it may help others recover from similar issues.
I dropped my ZenFone 2 (ZE551ML) on the kitchen floor the other day. When I picked it up, it was stuck in Asus Cover Mode, even though I don't have an Asus Cover. I was unable to get into the phone, so I forced a hard-reboot. After playing with it for a few minutes, I was able to get the home screen, though Cover Mode would intermittently kick on and off every few seconds. I got into the settings and disabled Cover Mode, but I soon realized that I had lost vibrate and haptic feedback functionality.
I took apart the phone to inspect for internal damage, and I noticed a small hairline crack on the flex cable connector that resides on the charger port board (see attached photo for details). The now-broken connector allowed the flex cable to shift laterally from its original position, leading to connectivity issues and causing the problems noted above. I was able to temporarily fix it by disconnecting the flex cable and reconnecting it to its intended position. As a permanent fix, I ordered a new charger port board from a vendor on AliExpress that ran me about $5 USD. I just installed it yesterday, and it seems to work as well as the original.
Click to expand...
Click to collapse
i had the same problem, did what you did and got the same result!
thanks for sharing info!
ben.anter said:
i had the same problem, did what you did and got the same result!
thanks for sharing info!
Click to expand...
Click to collapse
Glad I could help!
I got the same problem this morning. Tried the strong magnet mtd recommended in the asus forum but it didn't help. In the end, I found that by removing the cover, and then using your finger to flick on the magnet sensor (near the back button, bottom left of screen) works! After exiting the cover mode, quickly go to settings to disable it.
Thanks a lot
I had a similar problem , but my connector have gotten wet, and wasn't broken. When i cleaned it, the mobile got out from cover mode

Will it Worth replacing my screen again?

As I was playing with my Zenfone 2 the touch just stopped working.
The phone glitched out with thr flip cover mode and then back to normal.
And it wouldn't respond
Now after two months I've opened the phone and the touch won't work at all .
If I replace the touch screen that would be my second LCD replacement so:
Is it worth replacing the LCD again ?
Is there any possibility that it could be a motherboard issue instead of the touch screen.
adaa1262 said:
As I was playing with my Zenfone 2 the touch just stopped working.
The phone glitched out with thr flip cover mode and then back to normal.
And it wouldn't respond
Now after two months I've opened the phone and the touch won't work at all .
If I replace the touch screen that would be my second LCD replacement so:
Is it worth replacing the LCD again ?
Is there any possibility that it could be a motherboard issue instead of the touch screen.
Click to expand...
Click to collapse
that will be completely useless. neither it is a touch or screen issue not the motherboard. issue is either loose screws or bad sim flex. just open all the screws and open cover. close cover and tighten every screw firmly. if still the issue better turn of cover view. or change sim flex
sukhwant717 said:
that will be completely useless. neither it is a touch or screen issue not the motherboard. issue is either loose screws or bad sim flex. just open all the screws and open cover. close cover and tighten every screw firmly. if still the issue better turn of cover view. or change sim flex
Click to expand...
Click to collapse
Yeah I've cleaned the cable contacts and also the display cable was slightly folded.
Now touch works but as happen before sim speaker and fast charge won't work because of the faulty sim and data ribbon cable that's just 2$ replacing.
As I've changed two phones ( a Le 2 and now a Redmi Note 5 China AI) the Zenfone will finally replace my mom's crappy MTK6580 phone

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