You can find the schematic and other information here on nostalgiaair. Click on Schenatics then "Rider by Original Index", Sears and the model number. This will show tubes required by your radio.
Silvertone radios were made for Sears Roebuck. They sold a lot of tube radios in the 1930's, 40's and 50's. The 4586 would have been made in the late 1930's.
Norm
: I recently acquired a Sears Silverstone radio I am trying to find someone that might know a little history about the type of radio that I have such as year made, what year silverstone radios were produce, etc. I only see three tubes but there looks like there are two more places for tubes but they have caps in them. Everything on the radio looks as original as it can possible be. The settings for the radio are A.M., Foreign, and POL which I guess stands for Police. The serial number on the box is 747306 and the model number is 4586. I've looked on a lot of web sites but I could not find any 3.5' tall radio's like the one I have. Does any one know anything? Thanks for any help that you can give me. This is my first radio and I would like to know what books would give me the most information on silverstone radio's.