Yamaha CLP 330 keyboard mute!

by Nick
(Greece)

Hello there!

I need your help on a problem!

I own the CLP 330 and the last weeks when I begin playing the piano, suddenly after a few minutes the keyboard stop working! Like mute!
Therefore, the DEMO songs sound normally!

I have to unplug it, wait for moments and if I'm lucky sometimes it starts playing again for a few minutes. Sometimes is not!
I repeat that the DEMO songs and also the metronome are working perfectly!

What can I do? Please help!

Thank you in advance

Nick