Broken Clevo P751TM

[Maks0098]

When the charger is turned on, the indicators light up yellow. When the power button is pressed, the power indicator flashes green twice and that's it. I tried to reflash the main BIOS chip, I took out the CMOS battery, after that the laptop when I pressed the power button - the keyboard backlight started to light up, the fans started in turn, and then the backlight turned off and the fans rotated at 100% and the power indicator blinked orange. I also tried to reflash the EC, nothing helps. I also changed the video card to a known working one. First after power failure and first start - the above happens, and subsequent starts only the green power indicator blinks twice and that's it. Could the problem be in the video card power cable? Or is the problem somewhere in the motherboard or matrix?

[Maks0098]

I reflashed it using ch341a with a clip, just in case

[Maks0098]

and the BIOS that I flashed was from Dsanke. Maybe I flashed the wrong BIOS, because I have an i7-8086K and GTX 1080? Maybe I should try to buy a new i5-7400 or something similar to check if the processor might be the issue? and does this laptop support i3-7100, i3-6100? so that I don't spend money on i5 which is more expensive and I won't use it later