Nokia 1110 keypad failure

For nokia 1110 keypad problem :
1. Check / clean keypad connector (domsheet)
2. Trace keypad circuit for broken circuit with ohm meter
3. If the problem not solved resolder keypad IC, replace if needed
4. If the problem not solved, main processor probably broken/fail (CPU/Upp)
5. Resolder / replace main processor and reflash firmware