@blondiix so if it were me, I’d be looking for a pinched flat cable or a regular cable. Sometimes, a pinched cable is a short waiting to happen. When you apply pressure, the pinched wires touch and ground/short out and when you release the pressure the wires disconnect.
flat cables are harder to notice and sometimes they are actually grounding without any easily visible clues.
For additional help, Lenovo nicely provides you videos for the dissassembly of your ideapad:https://support.lenovo.com/us/en/solutions/ht509107-removal-and-replacement-videos-ideapad-s340-13-81um
Good luck and let us know how things worked out.