Hi,
My casio px-350 has exactly the same problem after 9 years of working fine. I have been googling for a few days now and there are a lot of people with exactly the same issue (also with other px models). Some have it within two years, so I would say its a design failure. A main board contains a lot of components so I would like to know which component is faulting here. I think Casio should know this by now or do they just replace complete boards without searching for the root cause?
Regards,
Wouter