With balance at "0", enter the sequence on the remote. Firmware Upgrading: USB Upgrade: Standard method for software fixes.

Typically supports LED panels for sizes such as 39" and 43".

If the TV is stuck on the logo screen or power cycles, a software update is required.

For HDMI or tuner issues, the schematic allows for checking continuity between connectors and the MSD6486 SoC. Common Faults and Solutions AliExpress

Here’s a controversial take from a repair bench: