One of the few post-1937 era sets by Radio Corporation of New Zealand that was released only as a Courtenay model with no Columbus version made.
Intermediate Frequency: 455kc/s
There were two different versions using two different mixer / osc valves - they break down by serial numbers as follows:
|VALVE||OSC COIL||SERIAL #|
65470 - 65600
|6SA7||R6535||77151 - 77650|
This is a rare glimpse into factory serial numbers and the number of sets produced for a specific model - which is quite low when compared with the tens of thousands of a particular model made by companies like Philco in the U.S. of A... but not unduly out of proportion when taking into account our far smaller market.
Second release service info (first release with 6K8 mixer/osc will have slightly different circuitry surrounding it):
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.