Galaxy S4 Active backlight is dim after AT&T security update of Jan 2017

Jeffrey Johnson5

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Sep 7, 2015
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Three days ago, I downloaded a security update from AT&T for my Samsung Galaxy S4 Active. After the update, the backlight on the screen is much dimmer than it used to be. I have all power saving turned off and the screen is set to 100% manual brightness. Also, the screen mode is set to "Standard". All of these are the same as the settings were before the security update from AT&T.

With the dimmer screen, there was also a darker stripe down the center of the display from top to bottom and from 1/4" from the left side to 1/4" from the right side. There was also some ghost imaging of the most recently viewed screen image. I played around with an app called screen fixer that flashes alternating green, red, blue, white, and black images across the whole screen. That seems to have eliminated the darkened stripe, but there is still some retention of the previous screen image.

Next, I disassembled the phone, verified that all the cables were already securely connected to the motherboard, unplugged all of them and plugged them in again, and this did not have any effect on screen brightness.

I wiped the cache partition and that had no effect. I also backed the phone up to the cloud then did a factory reset data wipe; again no improvement in screen brightness.

On two occasions since this problem began, the screen did go to full brightness when I turned on the screen, but as soon as I turned the screen off and on again, it went back to being dim.

Since the screen did go bright those two times, I'm inclined to think that the screen is either OK or it has an intermittent problem with the backlight. Note: The S4 Active has a TFT LCD screen with a backlight (unlike the S4 which has a super AMOLED screen). Another possibility is that there is an intermittent fault in the motherboard circuitry that powers the LCD backlight (at least that's my guess). Lastly, is it possible that the security update from AT&T somehow messed up the screen backlight?

Anyone else experience this problem?

B. Diddy

Senior Ambassador
Mar 9, 2012
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Moved from the Lollipop forum to the S4 Active forum, since this sounds like more of a device-specific issue rather than a general Lollipop issue.

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