My local guitar shop has a brand new Epi 339 that they are willing to sell for $350 out the door. Everything on the guitar is great except, the bridge pickup is not working properly. It works fine when the split pickup position is engaged but nothing in full humbucker mode. The guys in the shop guess that it's a loose wire. If that's the case, 350 is a good deal. If it's something more serious, 350 might not seem like such a bargain. Do you think it's just a loose wire or likely to be something more costly to repair? Thank you for your help.