The Columbus model 653 was manufactured for Columbus Radio Centre Ltd by Radio Corporation of New Zealand Ltd in 1955.

6-valve portable battery and mains radio with economy mode.

Notes on service info shows that, from testing 2 hours per day in full mode and 2 hours per day in reactivation twice per day this set will do 80 hours on fresh batteries in full mode, 130 hours in economy mode and 200 hours in battery reactivation mode (a form of simple trickle charging)

Valves (6): 1T4, 1R5, 1T4, 1S5, 3V4, 6X4

Intermediate Frequency: 455kc/s

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

1955 Columbus model 653 Schematic

1955 Columbus model 653 Parts List

1955 Columbus model 653 Battery Short Note

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.