iphone 5 no service when edge

I Have a waterdamaged iphone 5. After removing the shielding plates and cleaning the board with alcohol it was working again exept EDGE. In a 3g area it is working fine with good signal but when leaving the area into an EDGE area there is "no service". Any ideas?? Could it be the 77352-15 (Power Amplifier GSM / GPRS / EDGE)?