has 12v and 5v voltage
The CN8501 connector that goes to the led without voltages and even disconnecting has no voltage.
I used the adapted multimeter to test the LEDs (inside the multimeter I used a rectifier bridge plus a resistor of 10K or so) and applied to the pins of the connector that takes the voltage to the LEDs (the connector disconnected from the source board) to verify how I was the leds and noticed that on the led- and led + pins of a bar I got 10v in one and led- and led + of the other 20V.

whether or not the led bar connector is connected to the CN8501 connector on the power supply board, there is no voltage at the CN8501 connector

Change the LEDs

Model : 40pfg4109/78 40phg4109/78 40PFT4109/60
LED : CL-40-D307-V3 UBE12F01YT00S42S01231 UCF12F01YT00S3YF78969 40 "TPT400LA-HM06 SC1F TW - s.click.aliexpress.com/e/FLrYng5K

СКАЧАТЬ Philips+chassis+TPM14.1L+LA : Philips+chassis+TPM14.1L+LA.pdf

Sorry, I reported the wrong model of the TV, it is not 40PFG4109 / 78 but 39PFG4109 / 78
When disassembling the entire tv to examine the led bars I found that the defect is in some burned leds. Now what I need to know if the LEDs you use on this TV would be the LED code 3030 6v / 1.8w, the smallest positive terminal and the largest negative terminal.

CODES PRINTED ON THE LED BAR:

IC-C-TBAC39D192
11800586-B0
CLO_T39 PHPLD REV.02

SD F145 M8(P40)

Check with a multimeter