Your Sears radio was made in 1937 and has a tuning eye. A schematic can be found here on nostalgiaair.
http://ww3.nostalgiaair.org/schematics/SRC/_SRC_9-33.gif
Tubes and other parts are available from AES, tubesandmore.com .
Norm
:IBOUGHT THIS MODEL AT A BARN SALE FOR 25.00$ IT NEEDS A TUBE. CAN ANYONE TELL ME ANYTHING ABOUT THIS MODEL?