[Q] Broken digitizer, screen still receives "touch input" without digitizer??
I recently broke the outer glass/digitizer on my Asus Transformer TF300T tablet. Instead of replacing the glass right away (~$150, wtf?) I decided to take it apart and disconnect the broken digitizer (which wasn't receiving touch inputs because the glass shredded the ribbon) and put it back together. When I used it on my keyboard/mouse dock, at random the screen would freak out as if i was touching the upper corner. I went into developer mode to turn on the "show touch input" feature and it revealed that the device indeed DOES think i am touching the upper corner.
How is this possible considering the lack of a digitizer?
This is quite annoying to deal with just to use my tablet as intended.
Photos:
homeruntilly said:
This is quite annoying to deal with just to use my tablet as intended.
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Unfortunately the way it is 'intended' would be with a digitiser. Floating random voltages or whatever could easily cause this as there is an incomplete circuit where there should be a touchscreen.
SimonTS said:
Unfortunately the way it is 'intended' would be with a digitiser. Floating random voltages or whatever could easily cause this as there is an incomplete circuit where there should be a touchscreen.
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Would, say, electrical tape fix the issues on the connectors? the ribbon is broken by the glass and causes random touch events as well.
homeruntilly said:
Would, say, electrical tape fix the issues on the connectors? the ribbon is broken by the glass and causes random touch events as well.
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Highly unlikely. The problem is that when there is a digitiser in place the resistances are correct - by not having one there anything could happen.
SimonTS said:
Highly unlikely. The problem is that when there is a digitiser in place the resistances are correct - by not having one there anything could happen.
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thanks, I removed a small board that housed the digitizer connections and the micro SD adapter. this fixes my issue with the touch input, at the cost of the built-in micro SD card slot.
good thing the dock has one build in too!
Related
Hi,
I have just replaced LCD and digitizer of my HTC raph (first time) and there seems to be some kind of problem. It turns on, but the screen shows nothing just lights up a little bit and there are some stripes visible as if the lcd would be broken, but it's brand new. The stripes changes a bit as i press some buttons or touch the screen so the phone and touchscreen are working - the problem is with LCD.
I don't know if i put all the conducting tape to the places it originaly was. Could that be a problem? I double checked all the connections but still, might be a contacts problem?
Any thoughts on what might cause this?
Also the phone got kind of hot after having it charged for some time, is that normal?
Of course, this may be caused by a bad connection (but rather hard to go wrong slot), but at a distance hard to say something more concrete.
Best to check with the new flex.
Thank you for the answer, i will try changing the main flex.
The flex cables can touch eachother right? Since they're originally covered with conductive tape.
BTW, i also intend to change the lcd + digitizer... my question is:
how to apply the digitzier? lcd and digitizer came separated - do i have to solder/glue or whatever the flex (of lcd & digi.)?
The original was something like sticked together... reminds me on sellotape aka Scotch Tape.
Can you give me a some help?
thanks
The ribbons must be solded together, there's 4 contacts on them and they should not touch eachother.
The touchscreen acts weird just above the samsung logo when i'm using the s-pen. it's not accurate at alle (the line is drawn a cm from the point of the stylus) and movements are way bigger than what i'm actually doing with the s-pen. Is this only on my tablet or is it a general issue?
speedfreak007 said:
The touchscreen acts weird just above the samsung logo when i'm using the s-pen. it's not accurate at alle (the line is drawn a cm from the point of the stylus) and movements are way bigger than what i'm actually doing with the s-pen. Is this only on my tablet or is it a general issue?
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Are you charging your tablet? Because if I remember correctly, some reported that when charging GN it may have some problems with touch screen.
andromorph said:
Are you charging your tablet? Because if I remember correctly, some reported that when charging GN it may have some problems with touch screen.
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No, not charging. Just under the front facing camera i have the same problem. The problem is the magnet in the case i'm using!! The problem disappears when the case is not attached. This sucks!
speedfreak007 said:
No, not charging. Just under the front facing camera i have the same problem. The problem is the magnet in the case i'm using!! The problem disappears when the case is not attached. This sucks!
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Yes. Magnets are not good with a Wacom digitizer.
A Wacom digitizer acts by generating a small variable electromagnetic field. It induces a small AC current in the little LC circuit in the pen (that needs not be alimented). This AC current is then detected by the Wacom digitizer (present in the Note's screen) when it switches to "receiving" mode (it switches from send to receive mode many times per second).
In this way the Note knows where the pen is located.
Any magnet nearby the screen can disturb the signal sent and received.
It's not really a flaw in the Note's hardware or software but something that is inherent in how the Wacom digitizer works.
Simple solution: it's better to avoid cases with magnets.
(and that also explains why Samsung original cases don't have magnets... correct me if I'm wrong)
sphere314 said:
Yes. Magnets are not good with a Wacom digitizer.
A Wacom digitizer acts by generating a small variable electromagnetic field. It induces a small AC current in the little LC circuit in the pen (that needs not be alimented). This AC current is then detected by the Wacom digitizer (present in the Note's screen) when it switches to "receiving" mode (it switches from send to receive mode many times per second).
In this way the Note knows where the pen is located.
Any magnet nearby the screen can disturb the signal sent and received.
It's not really a flaw in the Note's hardware or software but something that is inherent in how the Wacom digitizer works.
Simple solution: it's better to avoid cases with magnets.
(and that also explains why Samsung original cases don't have magnets... correct me if I'm wrong)
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I bought the case of ebay, it's very good, but the magnets are not a good idea indeed. I'll try some shielding, but that will be quite difficult.
I'm sad to say I finally destroyed my TF300. It fell from about 6 feet onto tile. The screen is cracked in quite a few places, but luckily it didn't spiderweb. The touchscreen kind of works, I say kind of, because it's touching in random places all over the screen. So my question is, can I possibly unplug the digitizer only since the LCD works fine? That way I can use the keyboard dock's mouse or a USB mouse and still use the device. Thanks in advance for any help.
this happened to me as well. On youtube there are many tutorials of how to replace the screen..
they will show you how to take the back casing off
then you can just unplug the digitizer cable (its the yellow cable with two connections on the bottom right of the back of the tablet) this will disable the touch but if you go that far you might as well replace the whole screen you can get online for $50.
and make sure to take note of the digitizer revision number as asus makes 4 different types and only the one will work on your tablet when you want to fix it...its a number on the digitizer cable either g01 g02 g03 or one other i cant remember off the top of my head
schkeet said:
this happened to me as well. On youtube there are many tutorials of how to replace the screen..
they will show you how to take the back casing off
then you can just unplug the digitizer cable (its the yellow cable with two connections on the bottom right of the back of the tablet) this will disable the touch but if you go that far you might as well replace the whole screen you can get online for $50.
and make sure to take note of the digitizer revision number as asus makes 4 different types and only the one will work on your tablet when you want to fix it...its a number on the digitizer cable either g01 g02 g03 or one other i cant remember off the top of my head
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Sorry, I meant that I didn't want to fix the display, just disable the digitizer so that I can continue to use the device via HDMI. If I unplug the digitizer, will the LCD still work?
After unplugging the ribbon cable for the digitizer, most of the random touches have stopped. But now, even using the built in touchpad or a USB mouse, touches do not hold and can cause random presses to occur in various parts of the screen. Any ideas?
I'm not sure but could be a different problem? I've done the same to mine and my keyboard dock works just fine
savergn said:
After unplugging the ribbon cable for the digitizer, most of the random touches have stopped. But now, even using the built in touchpad or a USB mouse, touches do not hold and can cause random presses to occur in various parts of the screen. Any ideas?
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Spontaneous presses? This is at random, some tabs have it, others don't. That ain't from the keyboard; rather from either the digitizer, though detached it might be, or the TS board, or both in close proximity with one another. I've experienced this and still have no idea why. I've had perfectly good dig and TS Board do it when the board is left dangling and not screwed down to the magnesium frame. The only way to stop is to replace the digitizer. Or you can try to yank the dig's ribbons off the glass, as I've noticed ghost touches produced by a dig with partially torn ribbons (on the glass side) that were still connected to the PCB. The dig is not repairable anyways. You're risking nothing.
graphdarnell said:
Spontaneous presses? This is at random, some tabs have it, others don't. That ain't from the keyboard; rather from either the digitizer, though detached it might be, or the TS board, or both in close proximity with one another. I've experienced this and still have no idea why. I've had perfectly good dig and TS Board do it when the board is left dangling and not screwed down to the magnesium frame. The only way to stop is to replace the digitizer. Or you can try to yank the dig's ribbons off the glass, as I've noticed ghost touches produced by a dig with partially torn ribbons (on the glass side) that were still connected to the PCB. The dig is not repairable anyways. You're risking nothing.
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Do you possibly have any photos or tutorials that might be able to help me out so I don't cause anymore damage to the tablet?
savergn said:
Do you possibly have any photos or tutorials that might be able to help me out so I don't cause anymore damage to the tablet?
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Not sure where to start. If you've taken apart the thing before, i'd be easier. Remove the back. Turn off the service switch (Important). Otherwise, you might burn a coil on the motherboard. If you don't know what that is, look at the top of the motherboard. To the left of the power switch (thin amber ribbon for power on top side and volume on right side), there's a switch mounted on the other side but accessible from the top of the board. You'll see the printing "off" and "on" on this side. Slide it to "off" position. (Thumb attached shows location of switch at top, and where the ribbons should be cut off at bottom).
The ribbon part that's taped to the glass is hidden under the lcd. If you don't care, just snip it off where it meets the lcd edge. There's really no need to remove the lcd if you're not intent on replacing the digitizer. Again, since I am not certain what caused the ghost touches in your cases, it's possible they will continue. Hopefully, they won't. But at this point, the digitizer serves no function other than protecting the lcd surface on the outside. No need to save the ribbons.
To tell you the truth, I've tried using the tab with a dock and no touchscreen. You can live with it, but it's enormous inconvenience any way you use the device, from recoveries to roms to any app within. It's just not designed to be user-friendly that way. I eventually gave up and replaced the digitizer. You can find one for around $35.00 these days.
graphdarnell said:
Not sure where to start. If you've taken apart the thing before, i'd be easier. Remove the back. Turn off the service switch (Important). Otherwise, you might burn a coil on the motherboard. If you don't know what that is, look at the top of the motherboard. To the left of the power switch (thin amber ribbon for power on top side and volume on right side), there's a switch mounted on the other side but accessible from the top of the board. You'll see the printing "off" and "on" on this side. Slide it to "off" position. (Thumb attached shows location of switch at top, and where the ribbons should be cut off at bottom).
The ribbon part that's taped to the glass is hidden under the lcd. If you don't care, just snip it off where it meets the lcd edge. There's really no need to remove the lcd if you're not intent on replacing the digitizer. Again, since I am not certain what caused the ghost touches in your cases, it's possible they will continue. Hopefully, they won't. But at this point, the digitizer serves no function other than protecting the lcd surface on the outside. No need to save the ribbons.
To tell you the truth, I've tried using the tab with a dock and no touchscreen. You can live with it, but it's enormous inconvenience any way you use the device, from recoveries to roms to any app within. It's just not designed to be user-friendly that way. I eventually gave up and replaced the digitizer. You can find one for around $35.00 these days.
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Thank you very much for the information.
I don't plan on using it as a daily device, I just picked up my Note 3 the other day, and using the TF300 is going to feel like going back to the stone age. I really just wanted it to have basic functionality, because I still have the HDMI cable for it, and have XBMC and VLC installed on it, so I can play videos easily on my TV. It has Cyanogenmod on it right now, so really, it should be fine for a while. I could probably also hook up my dualshock 3 to it and game on a TV. Portable low-end console. I'll update the thread later if whenever I get around to cutting the ribbon cable. Thanks again.
How do you diagnose what to replace on your tablet? Is it possible with the tf700t?
Here is the scenario- I travel a lot and kind of pack my backpack tight and I think the extra pressure on the tablet has screwed the right side.. I turned on show touches in developer tools and a touch comes and goes from the right mid side (sometimes it moves) .
I was able tdeal with this for a while but now after my last travel it's made it almost impossible to use the tab. My tablet it is out of warranty, unlocked and rooted so don't know if I could sent it to Asus for repair.
My question is, is it my touchscreen I need to replace or is it another component? Currently I I hold the tablet and apply pressure on the right side (back) I can make the touch go and come. If I turn the screen off it will remove the touch for a bit. if the touch won't go away I try to apply pressure to the back in various spots to it goes away
My understanding is if you can see what's on the screen the display panel is good. If there are touch problems then you MIGHT need a new digitizer. It could also be that in bumping it around and what not that the ribbon cable connecting the digitizer has come loose. Heat sometimes seems to be involved in this happening too. There are a couple threads here about these issues, fixing them and how to go about replacing the digitizer yourself and where people have bought them. It's not a feat for the faint of heart but it can be done at home.
flhthemi said:
My understanding is if you can see what's on the screen the display panel is good. If there are touch problems then you MIGHT need a new digitizer. It could also be that in bumping it around and what not that the ribbon cable connecting the digitizer has come loose. Heat sometimes seems to be involved in this happening too. There are a couple threads here about these issues, fixing them and how to go about replacing the digitizer yourself and where people have bought them. It's not a feat for the faint of heart but it can be done at home.
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Thanks I'll check it out didn't know if it was the touch screen or digitizer. I'm typing on it right now so seems like touch is just fine.
I suppose I'll open it up and see if a cable is loose. But do you think Asus would accept it for repairs? It's unlocked and rooted.
They woud gladly accept it for repairs... but they would charge you a bundle. Your warranty is void since you unlocked.
Sent from my K00C using Tapatalk
Touch screen/digitzer I believe are one in the same.
Sure Asus will fix it. In/out of warranty. But as mentioned, they'll charge you big bucks. My guess to replace the digitizer would be about 300USD. MIGHT be a little less.
If you open it somewhere inside, can't recall position, there is a service switch you should turn off 1st, before you do anything else. That might keep you from frying some component should a short develop somehow. Just remember to turn it back on last before you finish inside.
I recall reading that the ribbon cable is held in place by either glue or double sided tape and the heat aids in its becoming loose and can be part of the problem with the digitizer getting all crazy.
BTW Anyone can feel free to correct or add to this....
Hi guys,
I have a Dasaita PX5 unit with Android 8.0 and 4 GB RAM.
I've bought it a few months ago and it was working fine until today the screen just went crazy.
The screen will start touching itself all over and enabling settings, or quitting my GPS software, or activating apps, or flipping through different screens etc.
I've tried to update the system software, update the MCU, and even a factory reset. The crazy screen issue still persist.
Any idea how and why my screen went crazy and how do I resolve it?
Thanks
Here is a short sample of what I meant by going crazy:
https://youtu.be/8ZcIXuc7MEw
I know exactly why and have had the same problem. There is a ribbon cable that comes out of the screen between the glass and LCD for the digitizer, its damaged the screens are so cheaply made the glass is still somewhat sharp and the cable kinks and breaks. . I actually just came on here to post if anyone knew where I could get a replacement besides Aliexpress.....
You should try reconnecting the ribbon cable, else just get yourself a screen replacement from where you bought the headunit.
I had similar issue where bottom part of the touch screen no longer register touches and as time goes by, the whole screen is completely "untouchable".
The root cause is that the ribbon between the unit and the screen panel connect to the mainboard is rubbing against the unit casing's sharp edges causes permanent damage. Fortunately, it is still under warranty and i have got a replacement panel, smoothed the casing edges and place some duct tape before replacing the panel.
BlinkyTrojan said:
You should try reconnecting the ribbon cable, else just get yourself a screen replacement from where you bought the headunit.
I had similar issue where bottom part of the touch screen no longer register touches and as time goes by, the whole screen is completely "untouchable".
The root cause is that the ribbon between the unit and the screen panel connect to the mainboard is rubbing against the unit casing's sharp edges causes permanent damage. Fortunately, it is still under warranty and i have got a replacement panel, smoothed the casing edges and place some duct tape before replacing the panel.
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I just tried it and it got worst. :S
Someone with the answer?