There were several different cabinets for this dual-wave model, and the Columbus models started one year after production began (because the Columbus brand name was not introduced until 1937, while the model 18 had been introduced the previous year under the Stella, Pacific and Courtenay brands).
The model 18 has 4 knobs, but some examples have 6 - these are vibrator power supply versions, designed to run from a 6V battery.
Intermediate Frequency: 456kc/s
Frequency Bands: 2
Chassis Notes(most schematics can be clicked to download a full size version)
Model 18 chassis, found in chest-style and tombstone cabinets, sometimes with a vibrator power supply. Dual wave. Radiomuseum has a tombstone without magic eye, and the schematic does not show one, yet many examples have an eye fitted. Production serial numbers have been noted in both 1936 and 1937.
The standard chassis has 4 knobs - although many model 18's have 6, which indicates a vibrator power supply is fitted and it is designed to run from batteries or mains.
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.
|1937||Columbus model 18 - this set|
|1936||Courtenay model 18|
|1936||Stella model 18|
|1936||Pacific model 18|