I just was moving this beast into a new rack and noticed that the left channel impedance selector was protruding slightly. When I touched it the spring tension forced it outward. It looks like the plastic "claw" that holds a small metal rod is broken (the remnants inside the cavity I assume).

I'm guessing I need a new selector at least, but even if I had that, I'm not sure how to position it in the hole. So, I'm asking where do I get the parts I need to reaplce it and how do I do that!

It's also a very early model, Nov '89 according to Fryette support.