Closing lid makes laptop unresponsive until all power is cut.

Closing lid makes laptop unresponsive until all power is cut.

I gave my UX303LA to repairs (its out of warranty) to get a broken lid replaced. That all went fine (and the broken WIFI antenna got fixed in the process, too). When it runs it runs perfectly, however:

Closing and opening the lid makes the computer completely unresponsive until both AC and battery are disconnected.

Unresponsive means: No BIOS, no Post, no power LED response to pressing the power button, no nothing, (except for battery charging LED if plugged into AC).

This occurs whenever the lid is closed and opened, irrespective of whether the computer is on or off at the time, and irrespective whether battery or AC are connected when closing and opening the lid.

Disconnecting the screen and wifi makes no difference. Removing the BIOS battery makes no difference.

So: Closing the lid seems to scramble something essential which means the computer doesn't start anymore. Only removing all power resets it.

Any ideas how to further diagnose the problem? The shop I brought it too originally seemed to not have a clue what it could be either.