My Casio CTK-4200 has dead keys from middle C to G (including black keys). How can I fix it? Am I able to redeem the warranty to have it fixed?

SOURCE: casio ctk 496 keyboard

Unplugging and taking batteries out for 15 minutes should reset it back to factory.

SOURCE: I fixed the dead keys on my Casio WK-200 keyboard. Now some...

Most of these have VELOCITY sensing and that involves two contacts per note. If the velocity sense on those notes is somehow not working, broken wire or trace on the board or short that MIGHT cause your problem.

SOURCE: My ctk 2000 casio keeps shutting off

Replace the batteries and get an AC adapter for it! These do NOT work when voltage os too low.

SOURCE: My CTK-2000 Casio won't turn on. It's plugged in.

Does it have a rubber power on button? If ss, it's probably worn oujt. Replace it.

SOURCE: My Casio CTK-496 Keyboard has three keys (2nd

First make sure a keyboard "split" option is not set.

Probably you are going to have to clean the key contacts. They are likely conductive rubber "pills" that are pressed onto a circuit board that has interleaved fingers. Clean both the black pills and the circuit board using ONLY 99% isoprophyl alcohol and Q-Tips.

Testimonial: "Worked perfectly. Keyboard plays like new. Thanks!"