gold mountian treasure spy how do you tune this thing ?

[miamidave]

I got this a while back and never did anything with it figured I would send it to the flea market if it works but cant figure it out.
looks simple enough on/off/tune knob, toggle switch and a little knob # 1-10.
the little knob spins freely both directions and has no stopping point.
any body got any ideas?
thanks

 

[Kentucky Kache]

This might help.