Hisense 40H4F no backlight but turns off after splash screen

[frannyjunk]

So I have this Hisense tv where the backlight does not come on. But when it is turned on, when I shine a flashlight on the screen, I can clearly see the splash screen then it turns off. I looked at the mainboard and was expecting to see bulged capacitors, but they all look fine. I unplugged the backlight from the mainboard, and get the same symptoms (i.e. no backlight, dark splash screen then just a black screen). Is this just a backlight issues? Do Hisense tvs turn off by itself if the backlights are unplugged or are bad? Or is this a mainboard issue?

TIA.

[frannyjunk]

[Diah]

no risk its just 40 size.... take the screen apart you will see the led defect

[lotas]

Basically, when the backlight doesn't work, Hisense triggers a protection switch and the power supply cuts off the secondary voltage.

[Diah]

Basically, when the backlight doesn't work, Hisense triggers a protection switch and the power supply cuts off the secondary voltage.

this is early version from Hisense.. 1080 pixels not 4K or later no protection , and the LED they used as direct LED or Edge one was with zener protection , which they are now with old of production dead already.

[frannyjunk]

After some research, I located the reset button so I reset the tv. Now the backlight is still off, but the tv boot loops. Part of the protection circuitry? I have ordered the backlights from Aliexpress but they won't arrive for another 2 weeks. In the meantime, I am wondering if I should also buy a main board. Seems like a lot to spend on a 40" tv. Any guesses if the main board is ok?

[lotas]

I'm not familiar with this chassis and can't comment on this reboot, but it could be due to a faulty backlight. Try disabling the Wi-Fi module, then disconnecting the LVDS cable. If that doesn't help, try connecting to the UART and checking the boot log to see where it's failing. There might be an eMMC issue.