Even if the pop switch capacitor were shorted I'd think it would just be the same as if the switch were stuck closed, but you don't say that coil is locking on. Since you did find that wire hanging there I would make sure all the wires and diodes on the pop coil, pop activation switch and pop score switch on both pops were not screwed up by previous owner, maybe post a pic of those areas. Are you measuring the caps with one lead unsoldered also?