Bakelite 5-valve broadcast-band mantle radio.
Updated later to the model 502A with all-miniature valves
Little brother to the model 522.
Intermediate Frequency: 455kc/s
Frequency Bands: 1
Chassis Notes(most schematics can be clicked to download a full size version)
Note the unusual mix of Loktal and miniature valves.
Service information (Philco_-_model_502_and_522_-_5V_AW_AC_-_1955_.pdf) here