RSM Vol 25 - How To Fix A Receiver That Distorts

This 1947 training manual from the National Radio Institute provides a comprehensive guide for diagnosing and repairing audio distortion in vintage radio receivers. The text instructs technicians on how to identify specific hardware defects, such as leaky coupling condensers, gassy vacuum tubes, and improper circuit biasing, by listening to the unique character of the output signal. It details technical troubleshooting methods for the audio amplifier and loudspeaker components, including practical tests for off-center voice coils and damaged speaker cones. Additionally, the manual introduces a systematic training plan that encourages students to intentionally simulate faults to better recognize them in the field. By using signal tracing tools and voltage measurements, repairmen can efficiently isolate the source of amplitude and frequency distortion. Ultimately, the document serves as a pedagogical resource designed to turn novice students into skilled radio technicians through hands-on experimentation.