There's some big board, the driver boards (2 to 4 or those) and the interconnections.

But here's the big deal. There are no blinking LEDs or codes to tell you which. A TV tech also is aware of the LETHAL voltages as this area is not user serviceable.

There are web pages writing about a certain board but no tech will tell you it's that or the other thing. The shops here must give you the worst case repair price by law. Sometimes you get lucky.