Nakamichi DMS-2A CD tweaks?

A friend gave me an operational Nakamichi DMS-2A and I was wondering if there are tweaks or general modifications that may make this player sound better? Since it was free I'd like to use it as a "test" player. I'd like to start off simple of course with easy mods and I don't want to pour too much money into it. I'd just like to see how much better I can make it sound by making some basic mods or changes, one change at a time. I really enjoy music and my equipment. I get great joy from making it sound better. Thanks for all suggestions and answers.