I recently bought a 3 year old yamaha p-85/85 S and today I realised that it is a semi tone too high. The instructions in the manual to change the semi tone do not make any difference. I spoke to the previous owner who says she never changed the tone. Perhaps it has been like this for 3 years and she never knew. I play with other musicians so I need it to be in the correct pitch. I think it is supposed to do a factory reset every time I switch it on. If anyone has any ideas of what I should do I would be happy to hear them thankyou.