Diki: before you sit down to play the Tyros 4 in the store, check to make sure that OS version 1.02 is installed:
Function Button > Utility > Owner Tab > Version

If you want version 1.02 give me your email address and I'll send it to you.

I also recommend making one simple compressor adjustment:
Mixing Console Button > CMP tab > Gain Offset > set to: +4
* leave all other settings at flat (+0)

Then: Slip on a good pair of headphones and have fun playing & exploring Tyros 4.