Casio CTK-1100 Service Manual & Parts Manual page 16

EAA. Remove five rubber contact strips.
NOTEN One rubber contact strip differs in length.
<How to install rubber contact strips>
Lightly insert the tip of a rubber contact strip into the PCB.
Pull the tip from the back of the PCB and install it using
a tool such as tweezers. Do not forcibly pull it.
Rubber contact strips
– 1A –
This rubber contact strip differs
from the others in length.
CTK-1100