Look for little tiny holes in the sides of the knobs. If you look in them you will see a slot for little tiny screws (very tiny flathead screws) that are probably sunken in the knob. You probably have to loosen the screws before you can get the knobs off. I don't know for sure but I think this is your problem.

It apparently was just pushed in real tight or had a lot of dust and grime glueing it in, No set screws. Chassis came out fine after that. I'm taking my time cleaning it and checking it over. Thanks for your reply! Doug

:Look for little tiny holes in the sides of the knobs. If you look in them you will see a slot for little tiny screws (very tiny flathead screws) that are probably sunken in the knob. You probably have to loosen the screws before you can get the knobs off. I don't know for sure but I think this is your problem.

Perhaps put a drop of oil on the shaft when you put the knob back on.

Thomas