T510 Screen sometimes works

[nevakee11]

A while ago I posted because I couldn't get anything on the screen but I could on an external monitor. In the past 6 months it seems I've had some luck with my T510 but it is still giving me issues with the screen.

When my laptop has been off and unplugged for a while the laptop screen won't work. External monitor works and the Chrome remote desktop will still show my screen. After a while, I can see the screen sometimes in strange scenarios. If I do a screen extend I might be able to see it but can't disconnect the external monitor without it going blank. Sometimes I can see the screen if I have a certain window open in just the right position but if I move it then the screen goes out. Also, after my laptop has been plugged in and on for a while the screen will work by itself. However, if I open or close the lid slightly I get screen tearing or it goes out. My T510 has the nvidia professional

So what do you think system board, cables, or screen? How likely is each one a problem vs how easy/cheap would it be to test? Unlikely a software issue.