Zenith Mayflower 10" tabletop porthole 1949

[7"estatdef]

I just picked up one of these sets and on the front edge of the chaiss there are two numbered wheels. On the left is the one that tells which channel. On the right there is a smaller one that has a pulley hooked to the back of it. But it's missing the cord. What does it tell? Where does the cord go?

Too bad this set spent too much time in a damp basement. Most of the veneer has come loose and some of the plies in the plywood. The good new is that most of the veneer is there only a few chips missing. For the outside of the cabinet I made a large clamp using two sections of 1/2" all thead three feet long and two sections of 2 by 4. It was cheaper than pipe clamps and covers much more area. So with glue hypo in hand I've carefully put the puzzle back together.
Terry