Casio CZ/ VZ/ FZ - Pro Series

Hi,

I recently bought a Casio VZ1 with rom card and flight case for �48 
and I think there is a problem when switching on the synth.

When I switch on the synth I have to wait 4 seconds before I hear a 
slight click before I can hear sounds when I play a note. Is this 
normal or is there something wrong with my VZ1?

Please advise.

Arthur