The Mullard model 420 was manufactured for C. & A. Odlin Ltd by Philips Electrical Industries of N.Z. Ltd in about 1950.

Other radios based on the same chassis:

1950 Mullard model 420

Technical Information

Valves (4): ECH42, EAF42, EL41, EZ40

Intermediate Frequency: 455kc/s

Frequency Bands: 1

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

Mullard 420A (and probably Philips 208A) seem to use an AZ41 rectifier, and the transformer has a 4V tap for this.

The 420A also uses a Polar tuning gang instead of the previously used Plessey model.  This also means the aerial and oscillator coils are different to suit.  Dial tracking is apparently unaffected.  See the service note below. 

1950 Philips model 208 Schematic

1950 Mullard model 420

1950 Philips model 208

General Construction Notes for Philips Electrical Industries of N.Z. Ltd:

Model codes are explained on the Philips brand page.  Philips early-mid century were probably the Google of their time - they had branches in many countries and a global brand that everyone knew - and were apparently happy to let engineers come up with new ideas and implement them.  Construction is often overly complex but very well engineered - although repairs can also take a complex path.  They used time-in-motion studies to find the most cost effective way to asemble sets and sometimes this means repairs can be nightmarish (if you've ever worked on a V7A Theaterette this will be all too aparent).  U suffix model numbers are transformerless (hot chassis) sets and great care should be taken, or the sets avoided altogether.

Other documented models using this chassis (2 in total)

1950 Philips model 208