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LCD Backlight Error => Solved

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Posted at 9/4/2018 13:45:08     
Last edited by eschoi@huvitz.c In 9/5/2018 19:00 Editor

I am working with AIO-3399J and DM-M10R800
I compiled with rk3399-firefly-aio-linux-lvds.dts
and  I checked lcd_pwr_en is high , VDD-CORE is 1.2V , lcd_rst is high, 1.8V
and I checked LCD Board VGH =>5.59V ,  VGL=>-5.6V
AVDD=>11.2V ,VCC_LCD=>3.2V, LED+ => 4.97V, LED- =>0.0V
But LCD backlight is not working. tured off.
what position should I check?
I want to turn on LCD
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Posted at 9/5/2018 18:52:45     
Last edited by eschoi@huvitz.c In 9/6/2018 10:00 Editor

<Solved>
1.edit rk3399-firefly-aio-linux-lvds.dts
        backlight: backlight {
                status = "okay";
                compatible = "pwm-backlight";
                pwms = <&pwm0 0 25000 1>;
                brightness-levels = </*
                          0   1   2   3   4   5   6   7
                           <SKIP>
                        248 249 250 251 252 253 254 255>;
                default-brightness-level = <200>;  => default-brightness-level = <100>;  
2.check LED+ of LCD Board
LED+ voltalge should be higher than 11v
when  default-brightness-level is 200,  78% duty, LED+ voltage is 4.9v  => backlight turned off
but   if default-brightness-level is 100,  40% duty,LED+ voltage is 11.4v  => backlight turned on
pwm.jpg
Success!!!!!!!!
lcd_on.jpg


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Posted at 2/12/2025 10:07:02     
Have you fixed it yet? I was playing Chill Guy Clicker and my computer had the same problem as yours. Please help me.
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Posted at 2/13/2025 11:08:13     
Welcome to Quick Draw ! This is the perfect game for those who are passionate about art and love to challenge their intelligence. With each passing second, you will have to draw images for AI to guess. Can you complete them quickly and accurately to prove your talent?
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Posted at 6/5/2025 11:18:34     
LCD backlight error, solved! A common issue with a simple fix, often involving replacing the inverter or checking connections. Celebrate the win with a game of Wordle Unlimited to sharpen your deduction skills. Now, enjoy that perfectly illuminated display.

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