1. Pick out the keybord from Duo.
2. Remove all keytops.
3. Remove rubber sheet.
4. Apply Circuit Repairer glue on the terminal of the riverse side of the rubber sheet.
5. Put all keytop again after drying glue up well.
6. Cut stainless plate at the same pattern of the riverse side of keybord.
7. Pile up this plate to original steel plate and fasten them together.