[Arran]

Jayce;
  I can't tell you how Sanyo worked their dial cords, but on the two Rincan radios I have the pointer had to be rotated, and slipped through a slot behind the dial, which meant that you had to remove the plastic dial first, and obviously the knobs ahead of that. It's possible that the Channel Master has a screw or clip attaching the dial cord to the pointers, which has to be undone, if you can find a Sams for this radio, or post a question on the barking dog forum you may find the answer. All that I can say about Japanese electronics from this era is some of it was very crudely built, and not well designed, I hope that you can find a simple way around your problem and can get the chassis out, at the very least it will probably need the audio coupling caps changed, unless Sanyo used disk caps.
Regards
Arran