While the Courtenay-branded model 15 from mid-1935 was quite widespread and available until at least 1936, it is likely that very few Columbus model 15 sets exist - the NZVRS-member-owned model above featured in the NZVRS Magazine of November of 2003 and was noted as being a rarity. Most likely because the model 15 was a 1935 design and Columbus was introduced in 1937 - by then other 5-valve models such as the 24 and 25 had been released - This makes the existence of a model 15 under the Columbus brandname quite odd - and it might have been produced as an early example of the new brand moreso than a mainstream release.
If you have one, photos and serial number details would be appreciated.
Intermediate Frequency: 465kc/s
Frequency Bands: 1
Chassis Notes(most schematics can be clicked to download a full size version)
Model 15 series 1 service information RCNZ_-_model_15_-_5V_BC_AC_-_1935.pdf
Model 15 series 2 Service information RCNZ_-_model_15_-_5V_BC_AC_-_1936.pdf
The model 15 chassis was Radio Corp NZ's standard AC mains 5-valve broadcast-only receiver chassis for 1935. This is likely one of the first 'unified' chassis models where all brands got the same chassis with just their badge on the back to differentiate them (Previously different brands had their own peculiarities like painted chassis' or different valves and/or circuitry). Known to have been produced for Courtenay, Stella, Pacific and CQ.
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.
Model codes beginning with a 0, for example the model 051, are Osram valve versions of the model without the leading 0. Technically the 0 should be an O (for Osram), however the digit 0 was used throughout the site before this fact was discovered.
The E suffix indicates a magic eye option is fitted (in models which were available with or without, such as the model 25).
A and B suffixes appear to be simply updates to the current model, R also appears to be simply an updated model ('R'edesign, perhaps?)
P indicates either a permanent magnet speaker version of a model which also came with an electromagnet speaker (the model 26 for example), or a portable model (like the model 694P).
N and M indicated miniature valve versions of a model which started with all (or a mix, ie: model 5) of larger valves. One of these two codes may indicate a transitional mixture of octal and miniature - clarification is required.
S often indicates a stereo model. It can also indicate 'self-biased' in the transition period between back-biased and self biased sets where there were models with both methods employed (53S for example)
Finally, other suffixes and prefixes make occasional appearances in the RCNZ lineup - like the 66W (a variant of the long-running model 66) and the 75XA (a 10-valve version of the model 75 with a separate amplifier chassis).
|1935||CQ model 15|
|1935||Pacific model 15|
|1935||Courtenay model 15|
|1935||Stella model 15|