K5synth

Wow, never been used? It is probably worth $300 if you sell it to  
someone here on the list, assuming it is working & the display lights  
up (glows). Otherwise they are worth about $150 on today's market.

The K5 is a truly unique machine that is of most interest to people  
who like to experiment and make their own sounds. People who just  
want to play music in a band with standard "bread and butter" sounds  
like piano, strings and organ will find it is not their cup of tea,  
which probably is why your father didn't use it for 20 years. I would  
offer you $300 if I could afford it right now. I definitely can offer  
you $150 if you are willing to sell it for that price.

Joel