The Cossor Model 523, marketed as the Melody Master, is a British valve radio introduced in 1954 by A. C. Cossor Ltd. It was a relatively sophisticated domestic radio for its time, particularly because it could receive the new VHF/FM broadcasts as well as traditional long, medium and short waves.
The 523 is an interesting piece of British broadcasting history: it appeared just as radio manufacturers were preparing for the BBC's introduction of regular VHF/FM broadcasting in May 1955.
SERVICE MANUAL PREVIEW
The original Cossor service manual for the models 522 and 523 is available to members. The Melody Master 523 is the table radio and the 522 is the autoradiogram. Here's a taste of what's inside.
These pictures are faded on purpose, just for this preview. Members get the complete service manual, unfaded, to view and download.
The service manual includes:
- The full circuit diagram
- The specification and the valve line-up
- A description of how the circuits work
- Step by step alignment for FM and AM, with the oscilloscope response curves
- DC resistances of the coils and transformers
- Valve voltage readings
- The chassis layout and the FM box
