Re: headphone socket
Inc2 here. The headphone Jack has a few metal tabs that (over time) stretch inwards thus losing contact.
I ASSUME NO RESPONSIBILITY FOR THE FOLLOWING, PERFORM AT YOUR OWN RISK:
Using a Torx-bit (T5?) to remove the back housing will allow you to access the headphone Jack.
Use a fine-tipped flat head screwdriver to gently push inwards on the tabs.
Afterwards get a Q-Tip and squeeze/twist one end (making it smaller in size) and dip that end into rubbing alcohol, squeezing again to remove excess fluid.
Insert into the headphone Jack and twist in a Clockwise motion until the contacts are clean.
Reassemble and enjoy