Chosen Solution
My macbook ‘s screen suddenly stopped working and only displayed a black screen. The apple logo works, the startup jingle plays, but no screen, and external display also don’t work. I tried resetting all the things possible, and tried to remove and reattach the cables. nothing worked. Then I found out that once the display cable is detached, the external screen will work. After doing that, I found out that the laptop is fully functional. Does anyone know what is wrong with my laptop ?? is my screen the problem? Thanks !
It maybe the screen went bad but it might as well be a logic board issue. Ideally you should test with a known good screen if things get back to normal, that’s the fastest and easiest way. You probably have a shorted component that interfears with external screen circuitry but as for where the issue may be it takes some testing or known good parts.
You have a logic board issue within the MUX logic which sends the display output to the internal and different display connections. This will take some deeper skills to fix or your other option is just replacing the logic board.
