Internal Screen Intermittently Lights Up
My Macbook Pro works perfectly fine, until the day I dropped it. After that the screen does not come on, no picture even when shining through from behind with a torch. Was going for exam so I did not bother to fix after my first fixing attempt yielded no results. Left it for approximately 5 months, decided to try fixing it again after watching several Louis Rossman videos, took it out, turned it on, no power, plugged in charger, heard chime, screen comes on as if I was dreaming the whole thing. After a few hours, symptoms started to appear. The screen comes on once in a while. External display works flawlessly every single time.
Symptoms that I have experienced:
1) Does not light up at all, no picture.
2) Apple logo shows during boot, then screen goes dark but MacOS boots successfully.
3) No screen during boot, MacOS boots successfully, connect external display and showed desktop, disconnect external display and internal display returns.
4) Boots perfectly, when it sleeps due to inactivity, screen does not come back on when waking up
5) (May be coincidence due to not being able to reproduce 100%) When booting normally, no screen, forced restart to boot recovery mode, screen comes on as usual
6) Boots normally, but Apple logo shows very small logo(as if internal screen was some 4k screen) then suddenly changes to big logo(usual size), then boots normally
7) Boots normally, Apple logo shows, when desktop shows, display is fuzzy and broken all over(imagine a busted GPU)
All symptoms are discovered because I initially believed it was a software issue, and after several restarts, the symptoms does not point to software issue.
What I have tried:
1) Reset to factory
3) Re-sit display connectors to logic board
4) Take out battery and re-sit
5) Disassemble logic board to inspect for burnt parts(none found using magnifying glass)
Planned next step, disassemble monitor to check for loose IC. But anyone got any idea before I proceed?