Model 38 Parasitic Oscillation

Model 38 Parasitic Oscillation

This difficulty is sometimes caused by variation in the screen grid resistor in the second detector circuit (No. 21 in the diagram of Service Bulletin No. 166) from its original value of 0.5 megohms to 400,000 or 350,000 ohms. By correcting the low value of this resistor, normal operation is restored.

From the Philco Serviceman – April, 1935.