This symptom indicates that the primary power supply is functional, but the main processor is failing to initiate the boot sequence.
If you are currently debugging this board, let me know your TV is experiencing (e.g., completely dead, blinking light, or no backlight) and what tools you have available so I can walk you through the exact repair steps. Tp.mt5510i.pb805 Diagram
Hook up your multimeter to the LED connector pins and turn on the TV. You should see a voltage spike exceeding 100V before dropping down and stabilizing. This symptom indicates that the primary power supply