COLUMBUS MODEL 27 'EXETER' (1948)

The Columbus model 27 was manufactured for Columbus Radio Centre Ltd by Radio Corporation of New Zealand Ltd in 1948, it was in production for 3 years. It's part of the Columbus Exeter series of radios.

Other radios based on the same chassis:

5-valve dual-wave set.  Superseded by the model 27N which used miniature valves.

1948 Columbus model 27

The Columbus model 27 is part of the Columbus Exeter series of radios.

The models 27 and 32 were the dual wave and broadcast band (respectively) table models from Columbus in 1948 (although some early examples have been seen with a 1947 date code).  The cabinet style was pretty standard for sets from Columbus around this era, although later variants used the newer rectangular escutcheon without the step-down at the bottom that was so common on sets from around WWII.  There were quite a few variants, so expect to see a suffix letter of some sort

 

Model 32 - 6 Valve, Broadcast Band

There were at least 5 version of the model 32 over almost as many years.

1948 - model 32 - US octal lineup.
1950 - model 032 - US octal lineup, slightly rearranged AGC circuitry
1951 - model 032M - miniature valves }
1952 - model 032N - miniature valves  } differences not documented at this stage.
1953 - model 32A - miniature valves    } - its not clear why the 0 prefix was dropped for this final (?) variant

 

Model 27 - 6 Valve, Dual Wave (BC + SW)

Not enough variants have been sighted yet to note the differences.

The radios in this series are:

Technical Information

Valves (5): 6K8, 6K7, 6Q7, 6V6, 6X5GT

Intermediate Frequency: 455kc/s

Frequency Bands: 2

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

Original lab drawing for the model 27, 6 November 1947.  These lab schematics were distributed as photographs, presumably the quickest way at the time for them to mass copy information to allow Columbus Radio Centres and Turnbull & Jones service agents access to service info before the official documentation had been prepared and printed.

1949 Columbus model 27 lab schematic

Official schematic, 2 September 1948 - almost one year later.

RCNZ Model 27 Schematic

And changes noted in an example from 1950 - changes to volume and tone control, 6V6 grid circuit and power supply.

1948 Columbus  model 27 'Exeter'

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).

Model nicknames are often sourced from either newspaper advertising, company literature or the NZ Radio Traders Federation official trade-in price books (Particularly Courtenay models from this publication)

Other documented models using this chassis (3 in total)

YEARMODEL NAME
1948 Courtenay model 27 'Grenville'
1948 Courtenay model 26 'Grenville'