Nokia 1680c keypad not working problem, Keypad ic damage problem.
To solve keypad problem in nokia 1680c keypad problem first clean keypad touch and points on motherboard with electronics cleaner and dry with heat gun. If problem not solved rework on keypad ic or apply jumpers as shown in diagram below.
Nokia 1680c Keypad ic Jumpering Ways
Nokia 1680 Keypad Not Workig Solution