I have a very similar type unit, a Nakamichi CDC-3 that had the same problem. I found this link....
I spent about two hours fixing mine. The sled mechanism was binding somehow, causing random skipping. The first 10 minutes was getting it apart and figuring what was wrong, the remainder was spent getting all those tiny parts back in the proper place.
Look up the exact symptom before going at it (probably long skips). Set aside a long slow lazy day with nothing to do. DO NOT drink too much coffee, you will be handling tiny parts that go in tedious locations, so you don't need caffeine jitters adding to your misery. Take your time and be careful. It's well worth it. Mine plays like a new one.