Loose contact between screen and base (is it the base or screen?)

The base unit keeps disconnecting and connecting from the screen unit all the time, even if I do not move the book at all. Thus, an external mouse hangs or monitor gets black for several seconds. Also, there is a plug-off and plug-in sound of Windows all the time.

I have tried to clean the connectors on both sides with alcohol already, to no avail.

How can I identify, if the base or the screen is the culprit? If I had a replacement base, I could try it.

It seems that this issue also causes blue screens because when I use the screen only, there was no BSOD, yet.

Do you have any hints for me?