Marconi model T25DA Bakelite radio

Marconi T25DA radio. Cream cabinet with a gold lattice speaker grille in two halves, a tuning scale across the top and three red knobs along the bottom

The Marconi T25DA is a compact British valve radio from the early 1950s. It was designed as a relatively small domestic wireless set that could be moved conveniently between rooms, although it had to be plugged in to a mains wall socket.

It’s an interesting example of post-war British radio engineering, combining a five-valve superheterodyne circuit with an attractive cream-coloured cabinet and an internal aerial.

Valves

  • X142 – frequency changer
  • W142 – intermediate-frequency amplifier
  • DH142 – detector and audio preamplifier
  • N142 – audio output amplifier
  • U142 – mains rectifier

SERVICE MANUAL PREVIEW

The original Marconiphone provisional service information for the Model T25DA is available to members. Here's a taste of what's inside.

Front page of the Marconiphone provisional service information for the Model T25DA, with a photo of the radio
Front page
Top and bottom views of the Marconiphone T25DA chassis with the parts labelled
Top and bottom views
Circuit diagram of the Marconiphone T25DA
Circuit diagram
Drawing of the tuning drive cord and the table of valve voltages for the Marconiphone T25DA
Drive cord and valve table

These pictures are faded on purpose, just for this preview. Members get the complete service information, unfaded, to view and download.

The service information includes:

  • The specification and valve line-up
  • The full circuit diagram
  • Labelled drawings of the top and bottom of the chassis
  • The condenser and pointer drive cord arrangement
  • A table of valve voltages

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