The Columbus MC7 was manufactured for Columbus Radio Centre Ltd by Radio Corporation of New Zealand Ltd in 1948.

According to JWS the MC7 was appaling, and one of two sets made by Radio Corp.  The MC7 was followed up by the MC8 but after that RCNZ (mercifully?) stopped and went back to house radios.

Valves (5): 6K7, 6K8, 6K7, 6Q7, 6V6

Intermediate Frequency: 455kc/s

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

Power supply in a separate cabinet to the radio, with a 4-wire harness running between.

RCNZ MC7 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.