A small update on my Sony TV, as it may be important for future buyers: It seems when you switch to TV mode or start a connected HDMI device, the backlight tends to get out of sync. It introduces a small flicker then, a high frequency "humming" so to speak. Somewhere in the 20+ kHz. It triggers symptoms for me, hard to believe at first, but true. But I also found a way to avoid this: When you boot or reboot the TV's Android OS, after the booting process is complete, the backlight LEDs will be in sync. The high frequency flicker I referred to is not there then. Only if you switch to TV or to a connected (and started) HDMI device's HDMI port, then there is a chance the flicker will come back (in varying amplitude intensities each time). What does this mean exactly? It means every time the video input signal changes, the backlight turns off completely for a short moment. And when it comes back, there is a chance it got out of sync and has said flicker. This is clearly a engineering design fault, as the TV manages to sync the LEDs when it starts up. It seems the routines used for that are not active while the input signal changes, only 1 time at boot.

How to work around this?

1. Don't use the TV function (or ONLY use it, so it is active upon boot)

2. Every time you want to use an external device, do as follows, step by step:

  • Switch to the HDMI port without starting the device yet.
  • Then reboot the TV (by holding the remote's power button for 10 seconds).
  • While rebooting the TV, start the HDMI device before TV rebooting is complete, making sure the HDMI device itself is completely booted and having its final video output before TV rebooting is complete. (If the HDMI device needs longer to boot than the TV does, that's bad.)
  • Better look away as while the Sony logo is displayed during the boot process, the backlight flickers strongly.
  • Once booting is complete, the TV should sync its backlight properly.

You can switch between TV mode/Android apps, and also between HDMI/Android Apps without syncing issues, fortunately. But you can't have both TV mode and HDMI in the same session.
Remember this when trying any new Sony TV, as this design flaw might have made it into the latest TVs, too.

    KM It seems when you switch to TV mode or start a connected HDMI device, the backlight tends to get out of sync. It introduces a small flicker then, a high frequency "humming" so to speak

    Good find. Abysmally written firmware...

      I think this finding also applies to other devices too. I have noticed on my monitor something similar. It is minor, but I noticed that if my monitor was actually off all the way rather than just sleeping like I normally leave it, I would give the computer a moment to activate the video ports before turning the power on to the monitor screen.

      7 months later

      Hi there, on the 43X81J (2021 model, IPS panel) after the latest firmware update found a new entry in the "Quick Settings" menu called "Power Saving". It has 3 settings, Off, Low and High, and what it does it dimms the screen (among others?).

      @KM Do you have this, and if so, could you test it for flicker?

      • KM replied to this.

        Alyosha2001 I have purposefully never updated the TV, so it is still running Android TV 7.0. It does not have Quick Settings. However, it does have the regular Android TV Settings, and there is a Power Saving entry:

        Settings - Power - Eco - Power Saving - [Off, Low, High]

        The following captures have been made with brightness set to 5 and light sensor disabled; the distance to the TV is always the same:

        Power Saving "Off" (the flicker here seems to be the 60 Hz panel refresh rate flicker):

        Power Saving "Low" (20 KHz flicker):

        Power Saving "High" (still 20 KHz):

            Very useful, so Power Savings got to go! Really need an oscilloscope

            Any tips on how to get the brightness below 5 without the flicker?

            I recently bought a TV, but I don't think the blue light from the TV will affect my child's eyes, so I'm thinking about installing a blue light blocking screen protector?Is this a better way to protect my child's eyes, because I don't want my child to be short-sighted.

              fancy2022

              Most tv`s should have the ability to reduce the blue light in the color temperature settings

              Don't know about the flicker, though

                  KM Shouldn't PWM go to 0 on the lowest amplitude? Maybe it's another type of flicker

                    6 days later

                    KM Do you think that if I set the brightness to 5 and then set any of the R-Gain, G-Gain or B-Gain lower could trigger the PWM? (Would it be like forcing the panel to lower brightness than supported by DC Dimming?)

                    Also, could you tell me how to prevent the full black thingy (like when it turns off the illumination), as just watching a movie fading to black can trigger that.

                    I'm really trying to find the usable settings for it

                    • KM replied to this.

                        Alyosha2001 No PWM or backlight flicker here when changing the Gains, but always keep in mind my model is 2 years older and I use an old Android version.

                        To prevent the "black screen" flicker, I sideloaded the app "OnScreenClock 0.5.0k.apk" to permanently display the current time in a corner of the screen. It turned out, as I had hoped, that when some non-black pixels (the clock) are always displayed, the screen isn't recognized as fully black and the backlight won't go to flicker mode then.

                            KM

                            KM That's weird. Even if the brightness is set to 5? That means that it can have a brightness below 5 without the pwm if all sliders are draged to the left?

                                KM To prevent the "black screen" flicker, I sideloaded the app "OnScreenClock 0.5.0k.apk" to permanently display the current time in a corner of the screen.

                                Wait, you have a clock watermark when you're just watching TV?

                                    dev