Casio CZ/ VZ/ FZ - Pro Series

Keyboard matrix in synthesizers usually uses diodes.

But this looks like a problem with K16 line which brings signal from F  
and B keys. Cable? Connector? Check and clean.

Or some following component? Check Tri State Buffer 74HC241.

Daniel Forro

On 13 Jan, 2013, at 5:50 AM, misha.aaaaaaaaaaaaaaaaa wrote:

> Hello, I purchased cz-101. I`m very happy with it, as it works and  
> sounds amazing. But 6 keys do not working, I thought it may be  
> because of dust. But I cleaned it, and keys still not working. Also  
> I mentioned it is F, B keys on 2,3,4 octave. Is there an info, maybe  
> it can be a problem with resistors or chips (as capacitors looks  
> fine)? Of course I can manually check them, but there are a so much  
> components inside.
>
> BTW It seems there is a place for tablet lith batter on motherboard,  
> but  it is empty, shouldnt be there a battery?