[Nexus 7 (2013) General] GSLEON3:
I just wanted to report on a possible fix to touchscreen issues. While this may, or may not, work for you, it is what I did, what I have done on three(3) total devices & it is what has eliminated touch screen issues for myself & two other individuals.

This is a work in progress & I will be adding pictures & more detailed instructions, along with progress updates as I use the device going forward. This modification (though it really isn't a mod) requires no tools & while it does entail some light dis-assembly, it did NOT require breaking any seals that would void the warranty outright. Doing this however, may very well void your warranty, I am not an attorney, I am an engineer & taking things apart is what I have been doing since before I could even crawl nearly forty years ago.

To begin, I will go into my Nexus 7 story, which may allow you to identify similar symptoms.

My Nexus 7 device worked well out of the box, with only occasional multi-touch issues. As time progressed, the issues got worse & at one point a couple of weeks ago, even single touch event started to lag or not register. My Nexus 7 is a batch from July of 2013 & I purchased it in August of 2013, so it was still under warranty. Asus issued me an RMA number, however, I hate broken things, knowing darn well that 99% of the time I can fix them myself far faster than the total time it would take an OEM to get my device back to me. At any rate, after the 4.4 update, my touch issues got even worse. Aside from missing even simple gestures & taps, occasionally the screen would look funny & once it even had a sttatic "snowy" screen that was remedied by a factory reset.

After reading a few complaints from people about screen separation & investigating the device via the ifixit tear down, I decided I would take a look before committing to the RMA process. I gently slid my thumbnail under the bezel & slowly worked it around. Immediately I could feel the clips giving way & I eventually had the back cover off. Once the back cover is off, you will notice that the screen & digitizer ribbon cable runs across the battery, pinned in between the battery tray & the inductive Qi coil on the back cover of the device. I found it is easier to ease all the sides up slightly, then remove the back by gently lifing from the sides & upper portion, with the bottom, where the USB port is, being lifted up last. Once I removed the cover, I disconnected the battery terminal clip. After disconnecting the battery, I then followed the screen ribbon cable to where it is clipped into the screens board contacts with a plastic stay. Immediately upon applying pressure to the cable ribbon stay I felt & heard a faintly audible "click" sound. On closer inspection, I discovered that poor contact was being made by the ribbon cable & furthermore, the flex in the battery tray over time, when coupled with the heat generated at that location (due to the battery & the inductive Qi coil) can slowly loosen the ribbon cable stay & affect the quality of the connection. I used a thin piece of composite material to reinforce the cable ribbon stay & used a piece of vinyl along with a non-conductive adhesive to better secure the cable ribbon & stay. I only used a tiny amount so as not to affect the ability to safely disconnect the ribbon cable without destroying it. I also did not want a bunch of adhesive heating up & spreading to other areas. Before I performed the following step, I decided to test out a few thoughts. What I discovered is detailed in the next paragraph. So, after letting the adhesive dry overnight, I reattached the battery terminal clip & started the device. It has worked flawlessly since, without any touch issues.

While I had the back cover off, I carefully reattached the battery terminal clip & while wearing Nitrile gloves & standing on a wood floor to minimize the risk of static discharge, I would turn the device on with the display ribbon cable in various states of connection. They ranged from being angled so that the far contacts would make little or limited connection, to a full connection with varying degrees of pressure applied, to simulate a good or bad connection. Sometimes the device would not boot. Other times it would boot & have a static or "snowy" screen. Sometimes it affected all touch, from single finger events to multi-touch. It also surprisingly affected the system response. Things would freeze up & apps would FC or ANR. Again, once I improved the connection, everything was back to normal & functioning perfectly. In fact, it is functioning better than it did out of the box.

While I am sure Asus would argue that this voids the warranty, I did not break any seals. No tools were needed, just the materials I chose to use & had lying around. As I also mentioned in the opening, I did this on another household members device, that only had multi-touch issues, not all the issues I had, & their device has now been functioning wonderfully for the last several days. The display ribbon clip in their device was not completely detached on one side like mine, but it was fairly loose all the same. The third device was a friends & it was having mostly single touch issues, though he said multi-touch issues would come & go. We ran through the steps on Hangouts & his ribbon cable was in its place, but as he removed the back, the stay clip fell out. His device is also functioning normally now & he has not reported any further touch screen issues.

Since the problems people are having are oftentimes different & not consistent, it very well could be that this is exactly the issue. I would surmise that it could be the very reason why Google & Asus have been VERY, VERY quiet about the issue, since it would require returning the device for a fix, not simply a software fix.

If you try this, I urge you to be patient & use the utmost care when removing the back. While there are no cable attached to the back, you never want to force things. Be gentle & when you find the right spot for lifting, you will know it. It is not difficult & it is relatively harmless. I would caution you to use gloves & minimize the risk of discharging static electricity. I also recommend using gloves because copper sheeting is used in a couple spots & if you have ever worked with copper sheeting in electronics, you know that stuff grabs oils from your skin like crazy & you will end up leaving evidence in the form of an ultra-clear fingerprint that almost no solvent will remove. (Don't use solvents in your device unless you are a daredevil or know what you are doing).

So, that is my story & what worked for me & my small group. Ultimately, these devices are ours & it is up to each of us individually to pursue the fixes or mods that suit us best. That also means that the responsibility & consequences belong to each of us as individuals. What steps you are willing take to remedy any issues you may have with your device are decisions you need to weigh. This is XDA, where people take risks, assume that the are eventually going to brick their devices & make real modifications to devices (which this really is not). If you break something because you needed every single little detail & step spelled out for you, that's not my problem. Again, this is XDA, not some ragtime blog & anything you do here usually requires you to be able to think for yourself at some point.

Lastly, I will try to get to a step by step with pictures as soon as I can. I am not a developer, I am not a student & I don't have a ton of time to devote to answering questions. I will do what I can, when I can, but between the holidays & my job as a mechanical engineer (two large hospital projects are going on right now that take up 95% of my day), I have very little time right now. This post is the result of a large lunch review meeting, not free time, so it will probably take some time to get everything up. I have to recreate most of it, since I really figured on RMA'ing my device. I never expected this to work as it has for me.

Thanks.