The buttons losing connectivity sounds like the neck to body connection might have worn contact pads. Remove the neck and inspect the copper pads where the body’s pins land. If the pins have worn through the copper, then you (A) need to add a small bead of solder to the pads, or (B) replace the board. If the pads look okay and haven’t been worn through, try wiping them off GENTLY with isopropyl alcohol on a cue tip.