KDL-46HX800 - Bad Main Board or Bad LED Driver Board?

Hi all,

I have a Sony LED TV KDL-46HX800, It does not have backlight at all, when I try to turn it on, the it shows the green light for 3 seconds and then the red light blinks 4 times.

These are my new findings, I managed to bridge standby and power on and the led on pins a and tested all voltages on the power board, all voltages are OK even the ones that goes to the LED Driver, so no (LED_ON, VLED_VCC, GL_ERROR, 12V, GND) . I can see 3.3v, 12v and 24v. so power supply seems OK.

So I am thinking that this could be a main board or could be a LED driver board

II could not get backlights but if I disconnect the cable that goes from the led driver board to the t-con board, the tv turns on (no backlight and video) but I get sound, so looks like the main board is fine.

This is the diagram of my TV and all my notes are in yellow:

https://ibb.co/J3dQ7Dp

Could you please tell me if what I think it is correct ?

Thank you very much.