I have an old Acer TM4001 notebook. If the laptop is powered-off, with the lid closed, when I power it on, it generally works. Then, without touching anything, if I reboot the computer the internal display wil not work anymore. To make it working again I need to shut down the pc, close and reopen the lid and then turn it on. If I close and reopen the lid if it is not working after power the pc on, it won't work.

When the screen is working, closing and opening it has no effect (the data cable seems ok).
The external monitor always works as expected: If the internal display is not detected, the external will be the main (and only) display. This is not OS-related. When the screen is not working I cannot see the POST.

What could be the cause for this?