Casio PX-410R Service Manual page 18

24. Remove eight rubber keys.
25. Remove 32 screws and the key PCB.
*Precautions when assembling the rubber keys
1
The length of this only one rubber key is different.
2
The numbers of pins on the upper and lower sides are different.
3 Insert the pins and fix them tightly.
Seven Pins
2
Eight
Pins
— 16 —
Four
Pins
2
Three
Pins
1