Lenovo Legion 5 15ACH6H Starts, greeting sound, no picture anywhere

[dhs6512]

Hello. Lenovo Legion 5 15ACH6H 82JU PF303BT1, board HY660 HY661 HY561 HY572 HY56C HY57K NM-D562 Rev:2.0 2021-01-25.
Starts up, the keyboard backlight lights up, the sound of the Windows 11 password entry window loading is heard, the backlight brightness is adjustable on the keyboard,
when pressing caps or numlock there is an indicator, there is no picture either to its own or to an external one via HDMI. I checked the board under a microscope, ok, clean and untouched.
I threw in a matrix (FHD, 40 pin, 144Hz), flashed the BIOS (official, took the latest gkcn65ww and one earlier gkcn60ww), the behavior is the same.
I think that if the board has reached the window for entering the Windows 11 password, then the post is passed, all voltages are present and ok.
What signals could be looked at to localize the malfunction? Thank you.

[mcplslg123]

Tell us the original screen and replacement screen part number.
NM-D562 gives picture on HDMI without internal screen connected and i'm sure about it.
Share voltage on all edp pins.

[dhs6512]

Original screen B156HAN13.1 HW:3A FHD 40pin 144Mhz compatible with 120Mhz, test screen N156HRA-EA1 has the same specs as original. With or without screen no signal on HDMI. Measurements on test screen 40pin connector with new edp cable H560 EDP Cable 120Hz DC02C00RV10 REV.0A:
18,19,20,21 +LCD_VCC 3,3v 3 times up and 3 times down
27 HDP 2,5v 3 times up and 3 times down
32 BL_EN 0v
33 BL_PWM 0v
36,37,38,39 BL_PWR 20v always
22 selftest/nc 0
15,16 AUX lane three times cycle: up, 0, down, 0
LID_SW 3,3v always on JEDP1
thank you.