Hello :)
I'm generally new on this forums :) I hope we will cooperate for a long time :)

But for now I have big problem- to be specific- I removed fourth pin on microchip related to lockout problem. Then- i tested 82-in-1 game set. Everything seemed ok. 1s reset was gone, but... After soldering console back, it turnet that screen seems not to display anything- to be specific- it turned gray. When i turn on console, gray background is displayed and power led seems to be working correctly... Still, though, i can use gamepad to navigate through menus and start game, guided only by sound (sound output is corect).
So... Anyone know what happened?

Well, you aren't being locked out because the sound would indicate you aren't in a startup loop.

Make very sure the pin you cut isn't touching anything  else - any other pins or solder traces.