Asus Google Nexus 7- flickering bands across entire screen

[jon-M]

My trusty Nexus 7 has suddenly developed a sever screen flicker. It shows up as vertical bands moving laterally and very quickly / randomly across the entire screen, in a vertical form when the tablet is in landscape. In other words, the lines or bands run across the short dimension of the screen. The bands are of different brightness, and appear to flicker as they come and go very fast. I'd say that they appear at regular intervals, sort of like a sine wave of alternatining liighter and darker as you look across the screen, and the position of the light and dark peaks vary at a high frequency. It seems to be a sort of repeating pattern,Colours are not distorted. So far, I have entrirely rebuilt the software with a fresh Android installation after a factory reset. As this did not work, AND the flicker was evident during the Android installation process, suspecting a loose display connection, I then stripped and reassembled the Nexus' components, but the problem persists. I now suspect that one of the hardware components has failed, but have no idea which.
The tablet has not been rooted, and I first noticed the problem after connecting an OnTheGo cable to transfer a file onto the hard drive.

Any suggestions would be gratefully welcomed! Thanks, Jon

 

[B. Diddy]

Welcome to Android Central! Does it happen in Safe Mode as well? https://support.google.com/nexus/answer/2852139?hl=en

 

[jon-M]

The problems with banding / flickering are evident in safe mode.

 

[B. Diddy]

That suggests a problem with the hardware, or possibly the firmware. You could try manually reinstalling the firmware: How to manually update your Nexus or Pixel | Android Central. If it continues despite this, then it's a hardware issue -- take it to a repair shop.

 

[GSDer]

Hard to say if it's the display itself or the display driver.

When the device is in portrait orientation does the banding still transit across the screen from top to bottom, or does it change to going across from side-to-side?

 

[jon-M]

Thanks for the support / advice.

The banding on the device does not change when the device is turned etc- it always runs across the short side of the screen.

The suggestion to reinstall firmware is interesting, but I;d be out of my depth understanding-wise.
Would it simply be case of slavishly following the instructions?- they are clearly written, so it looks easy enough..

 

[GSDer]

It's pretty straightforward to reinstall the firmware; if you can tear the hardware apart and put it back together you can master that. If you're hesitant you could try something like Nexus Root Toolkit http://www.wugfresh.com/nrt/ (which is used for more than just rooting).

 

[jon-M]

In the couple of days since the last thread, the Nexus' problem has changed- the entire display has now completely changed in appearance. Colours are very washed out, and there is very low contrast. The black background is a pale grey. Icons are 'smeared'. My guess is that this is not related to software, but that the display is on its last legs. I'll plan to replace it, unless anybody has a different suggestion..
Thanks,
Jon

 

[B. Diddy]

I think you're right. Are you going to replace the display or the whole tablet?

 

[jon-M]

Hmmm..I'm not really sure. If I knew for sure it was the display, I'd replace it. But I'm realising that it could also be the video processing on the motherboard, or a connector cable, and don't want to swap old parts for new unnecessarily. Was thinking about picking up a cheapo Fire tablet and shelving the Nexus until another bright idea occurs to me.
.