Broadcast-band 5-valve radio available also as a tablegram. Tablegram version possibly known as the 'Carlisle' as seen in one advert.
4 different versions, 501, 501A, 501B and 501C - only minor differences between 501 and 501A, noted on the parts list and differences between B and C variants noted on their schematic below
Intermediate Frequency: 455kc/s
Model 501 and 501A Parts List:
Columbus model 501 and 501A Schematic:
Columbus model 501B and 501C 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.