I just got this piano from a familymember, and I can't get it to sound like an ordinary piano? The sounds it makes are really wierd, like electronic and I just want to use for playing classical music. Thanks! :-)
First, the D-20 isn't a piano. It is a synthesizer, which is a type of instrument that allows you to create a wide variety of sounds. The good news is that the D-20 was intended for creating realistic instrument sounds rather than just sci-fi bleeps and bloops. The bad news is that by 2013 standards, the D-20 is going to sound a lot less realistic than contemporary high-resolution sample-based keyboards.
If there isn't a piano patch on your D-20 already, then you may need to do a factory reset. According to page 263 of the PDF manual, the first three patches will be acoustic pianos, followed by a honkey-tonk piano and some electric pianos.