The Courtenay model 90 was manufactured for Turnbull & Jones Ltd by Radio Corporation of New Zealand Ltd in 1942, production ran for 9 years.

The model 90 was Radio Corporation of NZ's replacement bandspread model for the 75.  It was a 6 valve + magic eye set with 5 bands.

For detailed information, see the Columbus model 90 page.  Columbus and Courtenay model 90's were practically identical aside from the brand name on the dial.

Valves (6 + eye): 6K7G, 6J8G, 6B8G, 6J7G, 6F6G, 5Y3G, and 6U5 Magic Eye

Intermediate Frequency: 455kc/s

Frequency Bands: 5

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

1. Broadcast  (550 - 1600kc/s)
2. Shortwave (6 - 18mc/s)
3. Shortwave (14.85 - 15.73mc/s)
4. Shortwave (11.65 - 12.2mc/s)
5. Shortwave (9.45 - 9.75mc/s)

Note: the capacitors used in the tone cct are oil-filled and are often found to be leaky after all these years, making a mess under the chassis.  They are soldered into cups in the chassis and can be removed reasonably easily.

Sensitivity Tests

Volume control full on.  Tone control position 5.  Sensitivity based on x microvolts input to give 50mW standard output.

Frequency Input To: Microvolts
455kc/s Grid 6B8 5000
455kc/s Grid 6J8 80
1400kc/s Antenna lead through dummy antenna 2.5
1000kc/s Antenna lead through dummy antenna 3.0
600kc/s Antenna lead through dummy antenna 4.0
15Mc/s Antenna lead through dummy antenna 1.5
6Mc/s Antenna lead through dummy antenna 1.5
Bandspread Antenna lead through dummy antenna 1.5

1942 Columbus model 90 schematic

1942 Columbus model 90

1942 Columbus model 90

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.

All documented models using this chassis (2 in total)

1942Columbus model 90
1942Courtenay model 90 - this set