Screen not responding to touches anymore - plz help - Redmi K20 Pro / Xiaomi Mi 9T Pro Questions & Answe

TLDR: Screen not responding to touches anymore for no apparent reason. It's displaying everything properly, but it won't react to any touch.
Something weird happened to me today. I own a Mi 9T Pro. I received a second Mi 9T Pro with minor water damage at the bottom part (charging port area).
To make sure it was repairable I replaced the damaged parts with parts from my own Mi 9T Pro just to check if it's working. It was working.
I ordered replacement parts from AliExpress and today I put everything together. I didn't have the screen yet, but everything else had arrived. I connected my own phone's screen again just to verify that everything is working. And then it happened.
I turned the phone on. It vibrated and the Mi logo came up as usual, everything seemed normal. After some seconds, while the Mi logo was still on, the screen suddenly turned kinda turquoise for a bit, as though it lost signal for a moment. Quite like an old TV would do.
It did that two times. After that the booting was completed and I had to enter the PIN - at which point I discovered that the screen does not seem to be registering touches anymore. It's displaying everything properly, but it won't react to any touches anymore.
I shut it down and plugged the screen back to the phone it belongs (my own). And touching is not working on my phone now either ...
(Volume buttons work - screen shows the volume bar changing up and down properly.
Screen is about 2 years old and was working flawlessly before.)
Anybody got a clue what might have happened? Can it be saved? I've never had this happen before. Can it be that some replacement part/flex cable was faulty and it damaged/burned the digitizer? How can the touching suddenly stop working just like that?
I highly appreciate any input since having used the screen from my personal phone, I am now left without a phone
Thanks to everyone very much for your time.

you should check the screen cable , you might have damaged it.
Check the ribbon cable under a microscope , check the pins also , you might have bent them. (70% probability)
if not , then your digitizer is damaged somehow (30% possible)

Thanks very much. And either scenario is not repairable I guess, right?

pazof said:
Thanks very much. And either scenario is not repairable I guess, right?
Click to expand...
Click to collapse
On the contrary, both are repairable.
the first scenario is repairable relatively easier compared to the second scenario.
if its the ribbon , it can be repaired if you have the equipement and micro soldering skills, you can easily repaired the broken traces.
For the digitizer , there are some repair shops that have the equipement to replace only the digitizer, and keep the original screen, its not a DIY task really as you need a lot of equipement thats not worth doing it yourself.
Hope this helps.

It most certainly has helped, thank you very much mate. Have a good one.

Related

HTC Diamond Strange Screen Problem (URGENT)

I had my Diamond for about 8 months now. All of a sudden no matter where I click on the screen it always clicks on the top left corner (Start button). I hard reset the phone, changed SPL but nothing worked.
My Specs:
Duttys 5.2.20764.1.4.3
Diamond-hspl-1.24
When I try to align the screen it keeps on looping not letting me get out of the screen alignment. I have to soft reset the phone.
Is my phone dead? Do I have to send it to HTC for repair?
sounds like a broken screen digitizer (the plastic which recognizes touch).
If its under warranty then i suggest you flash everything back to factory, ie. stock spl, stock ROM. Then RMA it back for warranty.
If it isn't under warranty and you wanna get it repaired. Then just order a new digitizer from Ebay and install it yaself. That will save you an arm and a leg, since HTC will probably charge you like 4x the price to get it fixed.
How come it responds to the screen alignment than? When I press the cross hair it responds to it and moves to a different position.
Right now I am trying to put the stock SPL on the phone but I can't get past the screen alignment. The is synced and everything. Any ideas?
You MUST change the ROM to stock first then the SPL
I did put the stock ROM back on the Diamond. But I can't get passed the align screen. I tried deleting the "welcome" file form \Windows\StartUp but the file is protected and can not be deleted. Is there any other solution of by passing the welcome screen?
I had this problem too, I got my Diamond from Rogers and went home. After a few minutes this started to happen, and I instantly went back and got a replacement.
I got same prob. But sometime it work fine, after i do softreset i cant skip screen align. Can hard reset fix this prob? im from malaysia, how much it'll cost to replace the digitizer? thanks
i have this problem too
hello all!
I had the same problem as you! after some time searching... found a program called "Remote Screen Alignment" ... and your problem is solved!
Just google it!
caudex said:
sounds like a broken screen digitizer (the plastic which recognizes touch).
If its under warranty then i suggest you flash everything back to factory, ie. stock spl, stock ROM. Then RMA it back for warranty.
If it isn't under warranty and you wanna get it repaired. Then just order a new digitizer from Ebay and install it yaself. That will save you an arm and a leg, since HTC will probably charge you like 4x the price to get it fixed.
Click to expand...
Click to collapse
For the new diditizer is this easy to repair by myself??
I have a broken touch screen too (LCD is working perfectly, touch is non responsive, all over the screen)
I was just reading in another thread that changing the digitizer on its own is a bit of a nightmare as its glued to the LCD screen? Is this true, is this the case, if so, would it be possible to buy a LCD + Digitizer in one? I searched eBay but could not find anything?
Any help is much appreciated as the cost of a new phone is not an option!
Thanks,
DG.
DanGlee said:
I have a broken touch screen too (LCD is working perfectly, touch is non responsive, all over the screen)
I was just reading in another thread that changing the digitizer on its own is a bit of a nightmare as its glued to the LCD screen? Is this true, is this the case, if so, would it be possible to buy a LCD + Digitizer in one? I searched eBay but could not find anything?
Any help is much appreciated as the cost of a new phone is not an option!
Thanks,
DG.
Click to expand...
Click to collapse
Hi
My digitizer is also broken, I ordered new one from ebay (cost about 10 €) and as you wrote replacament is nightmare.
I'm trying to find a manual or instruction video but I cannot find anything.
If somebody knows how to replace digitizer please let me know or share a link for it.
Currently my best solution is to order new digitizer with display (cost about 20€) It is possible to order for exaplme here:
http://cgi.ebay.co.uk/NEW-FULL-LCD-...UK_Mobiles_Accessories_RL?hash=item518e98a7fa
Cheers
hello, i have the same problem with my diamond here, pres the screen and it activates the left upper corner, after a while stoped doing that but not my right lower part of the screeen doesnt respond. i mean i press the "j" and it writes "k".. u know what i mean., i cac calibrate the screen but after 1 min the problem is back. i wanna buy that digitizer and change it but b4 this i need a confirmation, did anyone do it and after that their diamond worked like b4? waiting for reply thx
This post is giving me a nightmare. I am facing similar problem only its not permanent. What I mean is it woks fine sometimes but wont respond sometimes. Sometimes it responds in the corners if I press hard. I think my phone is just passed its warranty also its 2nd hand though I have the bill. Service centers are really bad so I am scared.
Do you'll think my digitizer is gone bad or is it a software glitch?
Hi guys
I have a similar problem with my HTC Touch Diamond,
The screen just gone crazy constantly pressing on the top-right corner, this happened like 1 week ago. After searching the internet and this forum I found out that my only quick solution is to hard press the four corners to get working properly again but the problem will come back again after a while.
I bought this phone from ebay in 2008, had no problems with it untill I found out this ugly strange colored square in the middle that is noticable after switching phone's backlight off, I guess that was due to me holding the phone in my jean's back pocket (as I used to previous phones non touch ), I had this phone working perfectly until what happened last week!
I decided to find if this is a software related issue, so I upgraded to official HTC ROm 2.03.405.3 WWE, but the problem persists
I also bought a digitizer from ebay in case I want to replace it (but never done this before)
Can anyone please confirm if I am still under warranty, how to check this and if yes is that going to cost me anything to get it returned to HTC for repair (other than postage costs of course)
If not under warranty anymore, do you advise me to get a LCD+Digiztizer combined instead ?
Many thanks !!!
Damian
I have this problem (not my video):
youtube > watch?v=5-IUzerAT0s (sorry, I can't post links)
Problem:
Sometimes, and really just sometimes, no matter where I touch the screen it only signals a left touch. So wherever I touch, 1, 2 or 3 - only 1 will enter.
I am not sure if this is related, but it may give some clues:
A few days ago I disassembled my Diamond. I did not take out the LCD coz it's sort of glued in and probably hard to take out and may break.
However, I got down to the digitizer soldering. I did not de-solder the flat-cable, but I pressed my solder iron on each of the 4 solder joints. I pressed the solder tip right on the film. Don't worry, it's most likely polyimide and it's heat resistant.
After that the Diamond worked well, well, for a few days. Then same happened again. When I have the problem and I press strongly right of the HTC logo (LCD bottom right) the problem disappears. That makes me thinking the problem is maybe mechanical.
It maybe a solder crack. I presume the Diamond is RoHS, and my solder iron was not RoHS. That matters, coz RoHS solder needs more heat the lead solder. Means, my solder iron did not really melt the solder under the film.
I will give that another try with an RoHS solder iron in the next few days.
minidisco said:
I have this problem (not my video):
youtube > watch?v=5-IUzerAT0s (sorry, I can't post links)
Problem:
Sometimes, and really just sometimes, no matter where I touch the screen it only signals a left touch. So wherever I touch, 1, 2 or 3 - only 1 will enter.
I am not sure if this is related, but it may give some clues:
A few days ago I disassembled my Diamond. I did not take out the LCD coz it's sort of glued in and probably hard to take out and may break.
However, I got down to the digitizer soldering. I did not de-solder the flat-cable, but I pressed my solder iron on each of the 4 solder joints. I pressed the solder tip right on the film. Don't worry, it's most likely polyimide and it's heat resistant.
After that the Diamond worked well, well, for a few days. Then same happened again. When I have the problem and I press strongly right of the HTC logo (LCD bottom right) the problem disappears. That makes me thinking the problem is maybe mechanical.
It maybe a solder crack. I presume the Diamond is RoHS, and my solder iron was not RoHS. That matters, coz RoHS solder needs more heat the lead solder. Means, my solder iron did not really melt the solder under the film.
I will give that another try with an RoHS solder iron in the next few days.
Click to expand...
Click to collapse
I have the same 'tendency to go left' problem. From my experience, I found that the problem could be caused by heat. Here are some examples when it goes wrong: When I use Tomtom navigator while charging the battery, the phone really heats up and starts to go 'left'. When I try to text message under the sun after taking it out from my pocket. When I have high usage such as wifi + opera. Really hop somebody can come up a solution for the problem...
The Reason ---
Its a heating issue seen in 20% of all shipped diamonds. It heats and expands the digitizer causing loss of touch.
Solution ---
I'm working on it!
P.S - The heat i'm talking about is not the heat that's generated wile using the phone , its due to outside exposure.
Crazy thought - Try it at your own risk
Exposing the mobile to moderate temp (cold , say 12-14 degrees) might help. Not sure.. i said MIGHT.
Don't try this if its under warranty. And don't blame me if you did something wrong and all you circuits get messed up!
Anyways will post if i hit something on the way!
No, new solution??
Maybe change the digitalizer solves the problem?? Because two months ago the problem only stay few minutes but now i can't make the alignment process.
Thanks!

X1 felt down --> no display

Hey
A friend of mine called me yesterday if I wanna buy his broken X1 (it felt down :/) and repair it, because I'm the man for such jobs
Do you think it's only the LCD-flex-cable or another repairable damage?
I think I can get that device for 2-3 days and then decide if I buy it...
Some ideas? Is there any chance to repair it?
Thanx, Carbon
yes, probably even a loose connector on flex cable
Hello,
I am quite certain it is an easy problem, i have seen many x1 phones with just a minor loose connector which causes the screen not to respond.
The best way to check it if it really is just the screen/flex cable is to turn it on, and check if the side lights flash in all colors.
If that works the phone should work normally. (even if the screen doesn't work)
After opening:
Re-insert all the cables in the screen flex cable and check if it works..
if that doesn't work then replace the flex cable.
If the screen works:
Then check out the screen if it has any crack's or black spots.
In that case you will have to replace the screen/touch screen also.
Generally, if there is no physical damage to the LCD itself and the phone buzzes on startup with all appropriate sounds - replace the flex. Flashing lights are attached to the flex and are positioned ABOVE the LCD on flex connection, therefore will not light up if the flex is damaged and neither will the upper keypad and other less obvious things.
The flex replacement is not minor, just be aware of that. Bad falls are also the reason for main PCB damage, in which case there will be nothing you can do.
Thank you so much
It was a "very short" call by this friend, but when i take the device, I want a precise report what happened...
atm I don't now if the sidelights show reaction, but I will report
I'm afraid of a real PCB damage...
In flex problem side lights will not light up, as i mentioned, they are positioned above the Lcd connection, so if the main flex connection ribbon is damaged, as is most often the case, all of the upper level functions will be gone, but you will get a startup with buzz and sounds present.
I got it
And LEDs are flashing and you can start it complete normally, but you see nothing... i'm going to open it and check the Flexcable
Carbon386 said:
I got it
And LEDs are flashing and you can start it complete normally, but you see nothing... i'm going to open it and check the Flexcable
Click to expand...
Click to collapse
Best of luck.

HD2 Repair

Hey guys,
The USB port of my HD2 broke off and I was forced to replace the motherboard. When I assembled the HD2 again, I could immediately see that there was something wrong with my screen. The screen couldn't display full color (only bright red/orange/white/dark green/cyan accents). Also, the 'hang-up button isn't responding anymore after I replaced the motherboard (and flexcable).
What happened? Is there something wrong with the lcd display or did something go wrong when I (dis)assembled the phone? I took the motherboard and the flexcable from another HD2 that had a broken display.
Thanks in advance.
bilaba70 said:
Hey guys,
The USB port of my HD2 broke off and I was forced to replace the motherboard. When I assembled the HD2 again, I could immediately see that there was something wrong with my screen. The screen couldn't display full color (only bright red/orange/white/dark green/cyan accents). Also, the 'hang-up button isn't responding anymore after I replaced the motherboard (and flexcable).
What happened? Is there something wrong with the lcd display or did something go wrong when I (dis)assembled the phone? I took the motherboard and the flexcable from another HD2 that had a broken display.
Thanks in advance.
Click to expand...
Click to collapse
So you completely voided your warranty through HTC and tried to fix the device yourself, then screwed it up. I'd still say send it to HTC and ask for a repair. I don't know if they'll do it or not, unless you used official parts. I know they do out-of-warranty repairs, but they'll charge you.....
Yep you screwed up the repair, those ribbon cables need a delicate touch & any handfisted moment ends up with what you have got now ...
Another careful strip & inspection of all ribbon connectors is needed ...
I bought it as a second-hand phone. The guy didn't give me a reseat and the HD2 was flashed a WP7 ROM.
For the button problem, how are you turning your phone on without that button? do you hear/feel it click when you press it? If not its just misaligned.the buttons are on a flex ribbon cable with two holes on each side. it fits on the plastic middle frame of the phone which has two small spikes coming out of it... it has to be perfectly placed for your buttons to actually click..
if the flex ribbon is broken however you can buy one off ebay for arround 10$ any will do, mine is not original works fine..
for the screen you could have messed up the lcd, did you separate from the glass-digitizer? if you did you probably screwed it up.. its not a easy thing to do.. also was not necessary for your repairs
the connection to the motherboard might not be all the in and clipped which might cause your problem... (being that two of the little pins provide voltage and ground while all the others provide data information if one of those pins is not in all the way a piece of data might not be displaying for example a color. Never seen that happen its theoretically possible thou)
well I have only opened my phone 3 times and dont claim to be a expert.. but this is my take on it... Good luck!
@pablow Thanks for the detailed response.
The HD2 is only turned on, after I place the battery. Otherwhise it won't start.
I hear a click on the (broken) 'off' button, everytime I press it. I also noticed that the inside of not all of the 'spikes' are empty. I can see a bit of the flexcable in the spike of the broken 'off' button. The spike of the (working) 'call' button is empty.
I think that the flexcable hasn't been connected securely to the motherboard. I'll try connecting everything again tonight.
not that it makes much difference but HTC wouldn't of fixed it through warranty because of usb damage anyway
I thought so, thanks for the heads-up anyways.
[Solved] Display is fixed
Update:
I disassembled the HD2 and reconnected everything (from coax to flexcable). Fortunately it worked! The display is how it should be.
I have another problem now. All of the buttons don't work now, exept for the dial button. Do these buttons break so fast? It's annoying as fuark, because I have to disassemble it another time in the future to fix the buttons.
I also couldn't re-attach the volume control tab when assembling the HD2.

[Q] Repairing/assembling G1 -> broken volume rocker and touch panel

Well, I fixed my old broken G1 with new screen, touchscreen panel, case and keyboard.
Now I have 2 issue:
1) Sometimes my touchscreen goes grazy!! If I use the touch test application I see that sometimes when I touch the screen in an area there is another virtual touch in another zone of the screen. I read that it can depend from the current source when I charge the phone.. but I'm going crazy!! I opened my phone 10 times (I thought there was a problem in the cable that link TouchPanel to LCDPanel, because when I lock the cable with the clip it tends anyway to go out from the connector, now I put some scotch tape to fix but the problem is here.. so I think is another problem).
2) My volume rocker doesn't work!!
I bought 2 new keyboard to fix this problem, but no one of that fixed the problem. I thought the first new keyboard had volume keys broken, so I bought another one, but the problem persists!!
Now the Touch problem rarely happens, but the volume rocker is completely unusable..
Someone have experience about G1 assembling/repairing ?
Thanks and sorry for bad english
if you have put in multiple keypads have the same issue i would assume that it is the connection going to the motherboard. just a guess there but its either that or you have had a bunch of faulty keyboards.
only other thing would be a software problem
does the keypad work in recovery (let you go up down throughout the list) ?
as for the touch screen, probably need a new digitizer or flex cable, both are cheap and it sounds like you have the knowhow to replace them.
Ok, but digitizer is new!! screen also is new, and I have bought a total of 4 flex cable because I see that they are fragile (I broke the first I bought).
I tried to change flex cable but the problem remain the same.
The only thing that can be damaged is the LCD cable that links to the flex cable: it has a small cut where the cable have a curve, but the cut don't reaches the contacts (the cable is transparent). I also use some glue and scotch tape to mantein lock the cable.
The digitizer cable is connected to the LCD cable, and then they go to the flex cable that connect them to the motherboard.
The strange thing is that seems a software issue, because if I turn off and than turn on the screen, the problem is fixed for some seconds, minutes and sometimes hours...
Another strange thing is the possibility to control the screen with some metal objects from the moment that the virtual touch problem appear (I can control the screen also without touch it, with hand and piece of metal)
video:
have you tried a factory reset if you think it may be a software issue? if that dosent work you can try install a whole new rom.
really it sounds like it isnt the hardware since you appear to know what youre doing. i have a had a few phones that had screen (digitizer) issues and a new rom flashed cured it just fine
since you dont mind putting a few dollars into it, and your familiar with the inside, you can always try to pick up a cheap motherboard or spare phone from ebay or what have you, then swap the motherboard and you could then hopefully find out if it is the hardware or software
nagash91 said:
Another strange thing is the possibility to control the screen with some metal objects from the moment that the virtual touch problem appear (I can control the screen also without touch it, with hand and piece of metal)
Click to expand...
Click to collapse
Huh sounds like you got a cheap digitizer than. Most good digitizers use heat to touch. If it's literally touch, then sounds like its a fake/meh digitizer. i hate the digitizers that aren't heat, but press. I see them all the time in those first samsuck touchscreen phones. And they usually die in a bit. I had a Samsung behold with a screwed up digitizer
demkantor said:
have you tried a factory reset if you think it may be a software issue? if that dosent work you can try install a whole new rom.
Click to expand...
Click to collapse
Yes I flashed 3 or 4 roms after a wipe (I tried also super-wipe.zip), but the problem is here..
The digitizer works well some times, but sometimes get crazy (you can see in the video).
I don't that my new digitizer is fake, but I really don't know!
BTW I'm trying to repair my phone for fun (now I have desire z) and because I am fascinated by my old G1.
PS:
I see another strange issue--
If I touch the screen when the phone is on a table the screen digitizer is not very sensitive and can't take input from fingertips.
If I touch the screen when the phone is in my other hand, the screen digitizer is a lot more sensitive and it take input from fingertips.
My impression is that there is an electric field or something similar that disturbs the digitizer, and when I take the phone in my hand I discharge that field to ground. Also when I turn off the screen, seems that the electric field discharge so when I turn on the screen is ok, but after some seconds the field returns to disturbs the screen.
I really don't know, but is the impression that I have.. something that is not shielded.
Now I'll try to use my phone in airplain mode.
Thanks guys, I'm happy to see that this forum is still very active

New display assembly won't work

HI guys,
I want to post on behalf of a friend who has a problem with his Xperia Z1. He originally bought it used with a broken display, he then changed it with success, the phone was working fine until it fell. At this point the display was still working but not the touchscreen, so he ordered a new assembly from the net (not genuine, like the first one which worked tho).
Upon receiving his new assembly, he immediately started the repair. However, when he turned on the phone, he only felt the vibration and nothing appeared on screen. No any light, he got a totally black display with no sign of life, while the phone was fully charged, and was recognized by Windows (he could even access his files on the memory).
He obviously thought that the seller tricked him and that the assembly was defective but when he tried with the old one (which had the display working but not the touchscreen), the same result showed up, no light, like the assembly wasn't plugged to the motherboard at all.
So far that's what I told him, check the connections to the motherboard, and make sure the flex ribbon is not damaged. He even bought a new ribbon and installed it, with no success.
He read that the problem can come from the display ribbon touching the chassis, thus making a short-circuit, but I doubt it. How if the display connector on the motherboard is broken? Is it fixable? Like buying a brand new connector and soldering it.
Thanks in advance for helping us
Try a hard reboot by Golding vol + and power until phone vibrates. Is the backlight working?
N10AP said:
Try a hard reboot by Golding vol + and power until phone vibrates. Is the backlight working?
Click to expand...
Click to collapse
Thanks for reading this long problem
Sure, he tried the hard reboot thing, he even successfully flashed a stock ROM but nothing changed. I can only think of this as a hardware problem, but what part is defective?
The motherboard connector?
The ribbons on the chassis? But he changed to new ones already!
The LCD assembly? Same, the one he tried is a new one...
Still no one to solve the mystery?
I'd like to add that the phone turns off itself after approximately 30 minutes in idle state. That is, the explorer doesn't show the phone anymore and it has to be powered on again.
I know the best solution would be to buy a new motherboard or just forget about this broken phone, but it's a challenge to fix something that is apparently hopeless

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