Reset to factory? - dissonance issue

[Player]

I recently bought a used Privia 110 to learn to play the piano. I've been a professional musician for years playing drums and some guitar. It sounds like there is some dissonance that I noticed in the grand  piano mode. I called a seasoned musician friend lover and he noticed it too. It seems to be the F# key most noticeable in the middle C octive sounds a bit flat. When I put the piano in the electric piano modes it's less or not noticable because of the fluctuating modulation. How does one do a factory reset on the Privia 110? Maybe that will help. Any other suggestions appreciated also.