MULLARD MODEL 520 (1940)

The Mullard model 520 was manufactured for C. & A. Odlin Ltd by Philips Electrical Industries of N.Z. Ltd in 1940.

Other radios based on the same chassis:

5-valve dual-wave set, electrically similar to Philips 152

Mullard model 520
Farmers Trading Co., Auckland Star 29 August 1940

Technical Information

Valves (5, with magic eye on some): ECH3, EF9, EBC3, EL3N, AZ1

Intermediate Frequency: 472.5kc/s

Frequency Bands: 2

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

Philips 152, 153, 155 and Mullard 531, 520, 620 Schematic

Philips 152, 153, 155 and Mullard 531, 520, 620 Coils

Philips 152, 153, 155 and Mullard 531, 520, 620 wiring

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

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.

Philips model codes are complex - they are explained in-depth on the Philips brand page. 

Mullard codes: The model codes from Mullard sets (unlike their Philips counterparts) appear to contain valve count and date information.  For example, the model 525 is a 5-valve 1945 design.  The 2 appears to just be an identifier (most likely in case there were two models in 1945 with 5 valves, which there was - the 515 is the small 'Meteor' mantle set).

Fleetwood codes are often just a rearranged version of the Philips code.  For example, the FL374T transistor radio is a rearrangement of the Philips model L3Z74T.  Early Fleetwood codes were numeric with F on the end.  From about 1959 onwards the codes were much more like their Philips counterparts.  They start with F or FL (or sometimes FZ for larger consoles)...  These later codes also tend to end in a Philips-style identifier for the power source (A for mains, B for battery, T for transistor battery, etc - see the Philips brand page for more info on that).

Other documented models using this chassis (6 in total)

YEARMODEL NAME
1941 Mullard model 531 'Long Distance'
1940 Philips model 152
1941 Philips model 153
1941 Philips model 155 'Super Five'
1940 Mullard model 620