A
Looks like the pad has lifted and come off, but difficult to tell from the photo. Is it just a speaker/headphone - it looks like it. If so, check resistance between the inner two connection points. If you get a reading of a few ohms, maybe a few hundred ohms, then you can probably connect the wire to the connection point next to the one that you are having problems with. The inner two are probably where the thin copper tails go to the speaker voice coil. If this doesn't make sense let me know! Daz