The Columbus model 502 was manufactured for Columbus Radio Centre Ltd by Radio Corporation of New Zealand Ltd in 1952.

6-valve portable radio, battery or mains

90V / 9V battery

1952 Columbus model 502

Valves 1T4, 1R5, 1T4, 1S5, 3V4, 6X4

Intermediate Frequency: 455kc/s most likely

Frequency Bands: 1

Chassis Notes(most schematics can be clicked to download a full size version)

1952 Columbus model 502 Battery Plug

1952 Columbus model 502 Schematic

General Construction Notes for Radio Corporation of New Zealand Ltd: The first digit of the serial number typically indicates the year of manufacture of RCNZ chassis' (although not the decade - that requires a little knowledge of the valves, construction, etc). Sets from around 1934 onwards were often (but not always) constructed in a distinctive pressed 'baking pan' style chassis, seemingly unique to RCNZ.