First tell me about that copper pieces that came off... Update: man, your unit is in trouble.. It must be an important connector there. I've never tried repairing the same unit so I can't tell which part of the circuit it is or is it ok to leave it unconnected to others. If you know how to solder, you must scratch the board a bit(where that copper used to be) and search for a copper where it was used to be connected. To accomplish this, you might need a magnifying glass, and of course a "tester". Next you need to solder there the copper that fell off, or you need to replace with a new one (actually the soldering will do). But don't try it if you are not good at doing soldering with thin boards... I suggest you go to a professional technician to check it.