Screen flickers when displaying gray colors, happens less the longer the laptop is on

Discussion in 'Hardware Components and Aftermarket Upgrades' started by GreggoG, Dec 1, 2019.

  1. GreggoG

    GreggoG Notebook Enthusiast

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    I am having issues very similar to what is described in this thread.

    http://forum.notebookreview.com/thr...-on-gray-background-and-low-backlight.768500/

    My laptop is the Acer Swift SF714-52T. When the screen displays colors around 50% brightness like grays, there is a noticeable flickering on the screen, like someone is swapping back and forth from 100% brightness to 90% brightness around 20 times per second. My usual test is to open Microsoft Paint, fill the screen with medium gray, and the problem appears. (It appears in other ways but this is the fastest and most direct way.) I have some electrical components (phototransistors and resistors, in combination with my Arduino) on the way so that I can exactly quantify what I'm seeing.

    The issue seems to happen less the longer the laptop has been on. Also, Acer laptops have a battery reset button on the bottom. I believe that this button physically disconnects the battery for as long as it's held. If I hold the button down for 30 seconds to a minute and then turn the laptop back on, the problem appears more strongly. But then as the computer runs, the problem decreases. Very rarely is the problem totally invisible.

    The fact that the screen exhibits this problem more strongly after it's been off (or battery disconnected) I think points to a buildup of electrical charge or something. And when power is cut, the charge dissipates, and the problem basically "resets." I'm not sure exactly how it works, I'm not an expert on LCD panels.

    I recently RMAd the laptop, and I included instructions in the box on how to reproduce the issue. I got the laptop back and the notes on the report said that the technician was unable to reproduce the problem. I thought I was going crazy so I asked my girlfriend to look at the screen to see if it was flickering and she confirmed that it was.

    I've tried everything I could find online about flickering screens. I tried uninstalling the screen in Device Manager, I tried reinstalling the display drivers, I tried seeing if I could change my displays refresh rate (I can't, it's locked to 60 Hz), and nothing has worked.

    Reaching out here to see if anyone knows what could be happening.
     
    Last edited: Dec 1, 2019
  2. N2ishun

    N2ishun Notebook Enthusiast

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    Have we tried ground loop isolation ?
    Get a cheapo 2 pin style extension cord and plug it into the wall with that....not 3 pin, 2 pin.
    It will isolate the ground in case it's your house wiring.

    Lots of problems stem from that and it does sound like something that is happening to you.

    Ever hear someones home subwoofer just start randomly humming ?
    Yea, it's like that.
     
  3. GreggoG

    GreggoG Notebook Enthusiast

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    The problem happens even when on battery. If that's the case, does your suggestion still apply?
     
  4. TANWare

    TANWare Just This Side of Senile, I think. Super Moderator

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    The problem may not be correctable on the system. An issue exists where the eye see's about 20-24 frames per second in reality. If you screen is designed where the refershe harmonic is close to the refresh of your sight, and of poor quality, you will see this more prevalently. Why high refresh is preferable, ie if 60hz you only get two-three pixels worth of changes, at 120 hz that could be 4 to 6 or so. This not only smoothens or stablizes the colors out but perceived motion as well.
     
  5. GreggoG

    GreggoG Notebook Enthusiast

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    I considered that it may have something to do with my eyes maybe being very sensitive to this, but when I checked my laptop this morning, the problem didn't appear at all. Then later today, the problem only occurred slightly. If it was an issue of the frequencies between the screen and what I see, then the symptoms should always appear.
     
  6. TANWare

    TANWare Just This Side of Senile, I think. Super Moderator

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    Not true, if the screen is a lower quality slight differences in temperature, power draw and other variables can make a difference. Even you won sight can vary by the amount of energy your body has to expend. Ambient lighting cam affect the issue as well.
     
  7. GreggoG

    GreggoG Notebook Enthusiast

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    FWIW this is an expensive laptop, and the screen is actually very nice. In terms of controlling variables, by using the battery reset button I was able to go from subtle flicker to significant flicker in under 2 minutes. So I don't think anything about me or the ambient lighting has changed, leading back to the laptop being the issue. XD
     
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