COLUMBUS 810 'SOMERSET' (1958)

The Columbus model 810 was manufactured for Columbus Radio Centre Ltd by Radio Corporation of New Zealand Ltd in 1958.

Other radios based on the same chassis:

7-valve + eye dual-wave radiogram, magic eye tuning.

This is the radiogram version (Somerset) of the Columbus 810 and has two speakers as shown on the schematic, while the table cabinet verion (the Plymouth) has one 10" x 6" Elliptical speaker fitted.

There is a model 810S, with a different circuit - a stereogram.  This model, the 810, is mono

Technical Information

Valves (7 + magic eye): 6BA6, 6AE8, 6BA6, 6AV6, 6AQ5, 6AQ5, 6X4 and EM80 Magic Eye

Intermediate Frequency: 465kc/s

Frequency Bands: 2

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

Service note from the schematic:

Distortion: check leakage on R/G switch - B+ to diode load

Columbus model 810 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.

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).

Other documented models using this chassis (2 in total)

YEARMODEL NAME
1958 Columbus model 810 'Plymouth'