[LarryFS]

Welcome to the Phorum!  I think the part is a long ago replacement electrolytic cap.  The schematic for the radio calls out four electrolytic caps - 16 mfd (item 31), 8 mfd (item 82), and 10 mfd and mfd 20 (item 84).  The 10 and 20 mfd ones appear to be in one can and the other two in separate cans.  These  cylindrical cans should be standing vertically on top of the chassis.  They will be marked on the side with their values.  That info may be obscured by other items.  My guess is someone had reason to replace one electrolytic cap and added the 47 mfd cap under the chassis.  It might have been the 20 mfd cap since its in the same can as the 10 mfd cap. Using a higher value of 47 is not unheard of either. Tracing the wiring in the schematic should tell you which cap it replaced.  This is not an easy radio to work on.  It seems crowded under the chassis and I saw two bakelite blocks which have caps inside, potted with a tar like substance.  On the plus side, there is a lot of documentation.