Casio AP-22S

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4. Certain keys do not function
5. A certain key does not function
Replace the main PCB.
Do the keys function?
Yes
No
Replace keyboard PCBs.
End
Clean the contact.
Does the key function?
Does the key function?
Yes
No
No
Replace the key contact rubber.
Replace keyboard PCBs.
End
Yes
Does the key function?
Replace the main PCB.
Yes
No