Location would be a help in most cases, but wherever you are, you'll find the value of a 30 year old organ is very low, almost zero in many cases.
The DX500 was the base model in Kawai's DX digital series, that I introduced to the world in Spring 1982. Very good flute voicing and a real leslie gave it a firm foundation tone. Strings were a bit bright, but a pull backwards on the Brilliance slider helped the DX models calm down a little. Alas, the rhythms were not digital, we had to wait another two years before we got that with the X series.
Product Specialist, Kawai. 1976-1989