So the output jack on my guitar has been screwing up alot recently (past two days). When I plug in, it produces feedback and no sound comes out of the amp when I play. When I fidget around with the chord it makes a crackling sound and I can sometimes get it to work. I have tried loosening/tighten the nut with varying but mostly unsuccessful results. I have played through multiple cables/amps with the same problem, so its definitely a problem with the guitar. Is there any way I can fix it short of opening the guitar or getting it repaired by someone else?