Hello
I received from a friend from Norway a faulty TCL U55C7006 TV
TV had a white power led on when powered on, later the LED went off, but no picture.
Initially i thought that it has a bad backlight. I tested the led strips with a tester but they proved good. I also checked the screen with a powerful flashlight, but no sign of any signal on screen.
I made some research and i discovered that the TV is an Android TV and the fault i have is often connected to a firmware problem.
I downloaded some firmware images and made some trials.
I tried with 3 different USB sticks, size ranging from 2-8GB, formatted FAT32 (in the end i also tried FAT16) and different firmware images. I used USB sticks with leds to check activity.
When i power on the TV, LED shortly lights on, then off.
Sunday i forgot the TV on and i left. When i got home, i saw that the TV has backlight. I flipped it over and i saw some pinkish garbage on screen. I switched off the TV and back on.
This time it had the TCL logo, later animated, then the Android logo and eventually it booted normally. I got a screen saying (in norvegian language), that no device is connected to HDMI3.
This proved that none of my firmware writing attempts was successful. but also the fact that the display itself is OK.
Tried to enter some menu with the joystick, nothing happened.
I thought that probably the joystick is faulty. I programmed a universal remote for this TV, when i got back, the TV did nothing with the remote.
I switched it off and back on, but since then only the pinkish garbage, sometimes the TCL logo, but TV does not boot.
I obtained the service manual but until now i didn't find any abnormal voltages.
As i see it now, one secondary voltage does not work correctly and stabilizes in time. The motherboard is powered only by 12V from the power supply. That voltage does not vary.
Of course, when i don't have backlight, the BL_ON voltage is missing. Other than that, i didn't see any differences yet.
Please advise.
I received from a friend from Norway a faulty TCL U55C7006 TV
TV had a white power led on when powered on, later the LED went off, but no picture.
Initially i thought that it has a bad backlight. I tested the led strips with a tester but they proved good. I also checked the screen with a powerful flashlight, but no sign of any signal on screen.
I made some research and i discovered that the TV is an Android TV and the fault i have is often connected to a firmware problem.
I downloaded some firmware images and made some trials.
I tried with 3 different USB sticks, size ranging from 2-8GB, formatted FAT32 (in the end i also tried FAT16) and different firmware images. I used USB sticks with leds to check activity.
When i power on the TV, LED shortly lights on, then off.
Sunday i forgot the TV on and i left. When i got home, i saw that the TV has backlight. I flipped it over and i saw some pinkish garbage on screen. I switched off the TV and back on.
This time it had the TCL logo, later animated, then the Android logo and eventually it booted normally. I got a screen saying (in norvegian language), that no device is connected to HDMI3.
This proved that none of my firmware writing attempts was successful. but also the fact that the display itself is OK.
Tried to enter some menu with the joystick, nothing happened.
I thought that probably the joystick is faulty. I programmed a universal remote for this TV, when i got back, the TV did nothing with the remote.
I switched it off and back on, but since then only the pinkish garbage, sometimes the TCL logo, but TV does not boot.
I obtained the service manual but until now i didn't find any abnormal voltages.
As i see it now, one secondary voltage does not work correctly and stabilizes in time. The motherboard is powered only by 12V from the power supply. That voltage does not vary.
Of course, when i don't have backlight, the BL_ON voltage is missing. Other than that, i didn't see any differences yet.
Please advise.
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