I got the TV from a friend. He claims that no image but sound from the TV.
I confirmed that when shine a flashlight on to the screen, I can see the image. And this should be backlight problem.
I open up the TV and found a few leds failed. And now I am ordering a new set of backlight strips for it.
But there is something that I do not understand when checking the leds. I do not have an led tester. I only use a bench power supply. I first set the voltage to 3V and current to 10mA. I could not light up the led until I increase the voltage to 12V. I understand most common leds are just 3V, I still have come across 12V such as in Sony TV. But the strange thing is, the current is more than 1A while others are usually under 0.5A. The TV is with 12 led strips and each strip has 7 leds. In such case, each strip is at least 84W (7 x 12V x 1A) and all leds totally is at least 1,008W (84W x 12). But the label on the TV just show 250W. May I know what is wrong, my calculations or my method of testing?
I confirmed that when shine a flashlight on to the screen, I can see the image. And this should be backlight problem.
I open up the TV and found a few leds failed. And now I am ordering a new set of backlight strips for it.
But there is something that I do not understand when checking the leds. I do not have an led tester. I only use a bench power supply. I first set the voltage to 3V and current to 10mA. I could not light up the led until I increase the voltage to 12V. I understand most common leds are just 3V, I still have come across 12V such as in Sony TV. But the strange thing is, the current is more than 1A while others are usually under 0.5A. The TV is with 12 led strips and each strip has 7 leds. In such case, each strip is at least 84W (7 x 12V x 1A) and all leds totally is at least 1,008W (84W x 12). But the label on the TV just show 250W. May I know what is wrong, my calculations or my method of testing?
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