Third of the 'Big Bandspread' models (the Model 75 was the first in 1940, the model 90 was the next, in 1948 and this models big improvement was push-pull output, perfect for high output. Some of the console-model 91's came with a big Goodmans 12" speaker, but most had an EM 10" speaker (91P had a permanent magnet 10" version).
Intermediate Frequency: 455kc/s (to be confirmed)
Frequency Bands: 5
Chassis Notes(most schematics can be clicked to download a full size version)
Notes on service material suggest HT is too high and to insert a 250Ω 10W wirewound just prior to the reservoir cap / field coil junction to drop the 300V to around 260V. Also use 5V4 as 5Y3 is possibly stretched in this role. Other notes on the schematics in the service PDF - some are difficult to read.
Service information (RCNZ_-_model_91_-_7V_PP_AC_-_1950.pdf) here
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.
|1950||Columbus model 91|
|1950||Courtenay model 91 - this set|