Nexus 7 BAD screen flicker!

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soccerwuedo5

Senior Member
Aug 26, 2011
71
35
Phoenix
With such overwhelming response, I hope to make this OP a brief hub of useful information.

Supporting comments:

Steps to reproduce for ALL tablets.

1. Weak WiFi signal.
2. Backlight dimmed to under 30%.
3. A program that constantly accesses the net. Such as Google Maps.
- - -

If you have a very strong WiFi signal (All bars lit up) the Nexus 7 will not flicker.

That is why the flicker went away on my Nexus 7 last night. I was sitting in a strong signal location.
When I went upstairs I had a weaker signal and that is when the flicker was noticeable again.

So, that tells me the WiFi chip in the Nexus 7 is a cheap piece of crapolla. :mad:
- - -

I think we have a few things going on..

- There is flicker from truly faulty displays (lines of pixels/panels going out, fluttering, etc.)
- There is flicker from Prism or some type of dynamic contrast.
- - -

Hi all, i can confirm that it's somehow software related. What i mean is not that the hardware is OK, but that software can fix it.

I thought it's somewhat related to the Nvidia Prism Technology inside the tablet, trying to setup the screen and optimizing something. It is related to this in my case. I rooted and used an app on the play store to stop that feature. Now i can tell you that both 4.1.2 and 4.2 are flicker free. Somehow on 4.2 this process is much more aggressive and i think that Prism is on all the time, not only when you are watching videos, even on the homescreen.

PS: ...the Prism Feature optimizes the screen, and it really saves battery...but you have some screen problems.

Fix mentioned above:
[GUIDE][FIX] Nvidia PRISM/smartdimmer
- - -


Supporting articles:

The Ultimate Nexus 7 Troubleshooting Guide: 6 Potential Problems and How to Fix Them
howtogeek.com said:
However, many people have also reported disabling Wi-Fi optimization removes the flicker. To do so, open the Settings screen, tap Wi-Fi, tap the menu button, tap Advanced, and uncheck Wi-Fi optimization. Of course, this will also impact battery life.
- - -
[fix] An easy way to solve the screen flicker with just a scotch tape
Pictures are dead but the claim is that scotch tape on the WiFi antenna solves the flicker (some disassembly required). This claim is refuted, but seems to work for many.
- - - - - -

Original post:
So I was very lucky to be able to go to Google I/O this year (don't hold it against me).

My Nexus 7 flickers horrifically when the brightness is at minimum and Chrome is loading a new page. I'm hoping someone (or a few of you) can reproduce this to make sure I don't have a lemon. If its something correctable by an ota update I'll keep my unit, but if not I only have tomorrow to exchange.

Anyone else experiencing this?
 
Last edited:

_dan

Senior Member
Nov 6, 2011
604
1,066
NJ
So I was very lucky to be able to go to Google i/o this year (don't hold it against me).

My Nexus 7 flickers horrifically when the brightness is at minimum and Chrome is loading a new page. I'm hoping someone (or a few of you) can reproduce this to make sure I don't have a lemon. If its something correctable by an ota update I'll keep my unit, but if not I only have tomorrow to exchange.

Anyone else experiencing this?

Can you take a video? I haven't heard anything like that. If anything it sounds like a hardware problem.

Sent from my SPH-D710 using XDA
 

soccerwuedo5

Senior Member
Aug 26, 2011
71
35
Phoenix
My wife and son are asleep in the room so I can't do a video. I found another thread about the One X getting an immediate update to cure screen flicker. I'll probably talk to the Googlers about it tomorrow, but I wanted to post a thread to be available for future queries.
 

Brac20

Senior Member
Mar 14, 2012
427
69
It seems to be a common issue with Tegra 3 devices. HTC fixed it pretty promptly so I expect Google/Asus will get it fixed even soon if it does turn out to be a common problem.
 

sulfobus

Member
Jun 29, 2012
19
2
This is an issue with Transformer Prime as well, maybe Nvidia still hasn't fixed their drivers. It has come and gone with different firmware updates, most recently it's back again... Seach for "transformer prime screen tearing" for videos of it. Does it look similar to what you saw?
 

soccerwuedo5

Senior Member
Aug 26, 2011
71
35
Phoenix
So the connection is the Tegra 3, then. Good to know.

My issue is not like the screen tear. Mine is the entire display flickers like it was backlit by a candle. I'm using Thomas Edison's tablet from the 19th century.

Also, it ONLY happens on page load in Chrome and with brightness below about 10% on the slider. I'll talk to Google today and relay what comes from that.
 
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Brac20

Senior Member
Mar 14, 2012
427
69
It sounds very similar to the HTC One X issues which were fixed by a software update. It's hard to say without seeing the screen flicker though as there seem to be various screen issues that people refer to as "flicker".
 

AndroidInsanity

Senior Member
Jan 15, 2012
1,432
300
Huddersfield
www.youtube.com
The HTC One X had the same problem.if not worse. Flickered on any brightness level on a grey background.but HTC fixed it so it is a very good chance it is software issue with yours. Give it a few months first?

Sent from my HTC One X using xda premium
 

Multisaft7

Senior Member
Jan 21, 2011
301
7
Is that really a Software issue? Because i am Order the nexus 7 from germany and think that There is the Support to Google Not good Because of no official release there

Gesendet von meinem GT-I9300 mit Tapatalk 2
 

RMXO

Senior Member
Feb 20, 2011
3,712
646
CA
So I was very lucky to be able to go to Google i/o this year (don't hold it against me).

My Nexus 7 flickers horrifically when the brightness is at minimum and Chrome is loading a new page. I'm hoping someone (or a few of you) can reproduce this to make sure I don't have a lemon. If its something correctable by an ota update I'll keep my unit, but if not I only have tomorrow to exchange.

Anyone else experiencing this?

Mine doesn't flicker
 

androidkid311

Senior Member
Jun 5, 2011
1,594
239
Issues already!! Whhooaa! Lol. Hope they roll out a fix! ;-)

Sent from my GT-I9100 using xda premium
 

mikesm1234

Senior Member
Jul 26, 2009
121
6
NYC
So the connection is the Tegra 3, then. Good to know.

My issue is not like the screen tear. Mine is the entire display flickers like it was backlit by a candle. I'm using Thomas Edison's tablet from the 19th century.

Also, it ONLY happens on page load in Chrome and with brightness below about 10% on the slider. I'll talk to Google today and relay what comes from that.

Sounds like some kind of power draw issue. Maybe a ticket with Google is in order.
 

soccerwuedo5

Senior Member
Aug 26, 2011
71
35
Phoenix
I got 2 in a row with the identical issue. They mentioned 2 or 3 other people came for the same issue. But, I'm happy to report that this 3rd one has no issue! Good to go, and loving it.
 

sahaskatta

Member
Apr 3, 2011
23
4
Does your Nexus 7 from google io take an extremely long time for screen rotation? I picked one up at the conference and did not open until today after the event ended. My unit sometimes takes as long as 30 seconds to rotate from landscape to portrait or vice versa.

FYI I have not tweaked or modified this tablet in any way. Just performed the software update after I was prompted to do so after setting it up for the first time.
 

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  • 3
    New Discovery

    If you have a very strong WiFi signal (All bars lit up) the Nexus 7 will not flicker.

    That is why the flicker went away on my Nexus 7 last night. I was sitting in a strong signal location.
    When I went upstairs I had a weaker signal and that is when the flicker was noticeable again.
    Today at work, I connected my newest Nexus 7 to my WiFi hotspot on my BlackBerry Bold 9900 which has a nice strong signal and that is why I thought I had a fixed one.
    When I changed my WiFi to a weak network and only had 1 bar, the flicker was present.

    I connected my old Nexus 7 (that had the flicker problem) to my BlackBerry WiFi hotspot and the flicker was gone.

    So, that tells me the WiFi chip in the Nexus 7 is a cheap piece of crapolla. :mad:

    Can someone with the flicker problem confirm that they do not have a strong WiFi signal when it is flickering?
    3
    It seems that on shutdown /system/bin/sensors-config will overwrite /data/lightsensor/AL3010_Config.ini. It must be pulling this data from somewhere else, like a special spot in flash memory where the factory stores the cal data. This implies that my factory calibration is borked, and it's not exactly a software problem.

    ---------- Post added at 08:08 PM ---------- Previous post was at 07:38 PM ----------

    Here's how to change the light calibration forever:

    Code:
    su
    mkdir /data/calibration
    mount -t vfat /dev/block/platform/sdhci-tegra.3/by-name/PER /data/calibration
    echo 880 > /data/calibration/lightsensor/AL3010_Config.ini
    umount /data/calibration
    rmdir /data/calibration
    3
    What box info do we need? I took a pic of mine before I returned my flickering 16gb version. I'm waiting to buy another one until I can confirm there's a way to tell it's a new non-flickering version.

    Mine has a label on both ends.
    One is English and the other is French

    On the English one there is a Customer P/N a P/N and a Check Number.
    Lets see if those are the same for all users.

    On the one I just picked up at Best Buy in Canada:
    Customer P/N = NEXUS7 ASUS - 1B16 - CB
    P/N = AB NEXUS7 ASUS 18/T3DL/16/1G/Y
    Check Number 0747

    Update
    So far no flicker on this new one. Doing the same things I did on the other one that flickers bad.
    One difference is they changed the initial start up screens a bit. Now after entering your gmail account info it asks for a credit card before giving you the $25.00 Play Store credit.
    My old one automatically applied the credit and sent me an e-mail confirming this. No credit card info required.

    New Discovery
    If you have a very strong WiFi signal (All bars lit up) the Nexus 7 will not flicker.
    That is why the flicker went away on my Nexus 7 last night. I was sitting in a strong signal location.
    When I went upstairs I had a weaker signal and that is when the flicker was noticeable again.
    Today at work, I connected my newest Nexus 7 to my WiFi hotspot on my BlackBerry Bold 9900 which has a nice strong signal and that is why I thought I had a fixed one.
    When I changed my WiFi to a weak network and only had 1 bar, the flicker was present.

    I connected my old Nexus 7 to my BlackBerry WiFi hotspot and the flicker was gone.

    So, that tells me the WiFi chip in the Nexus 7 is a cheap piece of crapolla. :mad:

    Here is the new setup screen:
    Setup.png


    This is new, used to just give the $25.00 credit automatically, now you need to provide a Credit Card before getting the $25.00
    Google%20Play%20Credit.png
    2
    Thank you for your work NASCAR. However we still need an official response from Google. We also need the Android sites to admit this.

    Steps to reproduce for ALL tablets.

    1. Weak WiFi signal.
    2. Backlight dimmed to under 30%.
    3. A program that constantly accesses the net. Such as Google Maps.


    All Nexus 7 units will experience this issue. There is no fix until a newer hardware revision is made. Again, that will take a few weeks. Screwing us over with limited RMA timeline.
    2
    My xperia x8, x10 mini, x10 mini pro, xperia arc had the same problems initially. They all were fixed every after software update.

    Even Cyanogenmod has settings tweak to reduce flickering when set in low brightness.

    I really believe it is caused by software. Backlighting LEDs are controlled by software via pwm. The pwm may be conking out and not producing enough voltage when there is high current draw from the wifi. But it don't do that when watching videos where the most current draw should be taking place. Probably because of the Tegra 3 energy-saving feature when watching videos, but I really can't tell. I am pretty sure they'll come up with a fix either set hysteresis not to adjust logarithmically, reduce wifi tx/rx power maybe, adjust voltage to pwm, etc. There are many ways to skin the cat so to speak.

    Sent from my Nexus 7 using xda app-developers app