If you are really attached to this piece of vintage gear and can afford to fix it, then yes it is worth looking at getting fixed. It may or may not be cost effective and there is risk involved with stuff like this. Depends whats wrong with it. Labour is expensive.

Is the one channel cutting in/out intermittent or dependent on the volume control? Any "crackling" sounds occurring when this happens?

I’m armed and I’m drinking. You don’t want to listen to advice from me, amigo.

-Max Payne