[MrFixr55]

Hi Ken,

My previous post went Bye-Bye. Don't trash it, fix it. If you do want to trash it, place an ad in the for sale section, someone wil find a good home for it.

This is not a horribly complex radio, don't give up!

Before going further, please note that this is a "warm chassis" set and that the power switch is in the B- / Filament return leg of the power line. Radio manufacturers have been doing this for years. With this leg of the power line connected to neutral, the chassis, through a 0.1uF cap and a 150K resistor, is also at neutral potential. Now, when the power switch is turned off, the chassis now floats to 120V through the cold tube filaments. Many of us move the switch to the "Hot" side (the rectifier plate and filament) and install a polarized plug.

Try the following:

If you have a similar radio, use it to determine the "environment" where you are repairing and testing the radio under question. Fluorescent, CFL and LED lighting, computers, monitors, UPS units, WiFi, 5G cell phones, digital TVs, the Internet of Things (Alexa, doorbell cams, Bluetooth, etc.) have wreaked havoc on the AM band. Use a radio that has an antenna loop but not a ferrite loopstick.

Review your work and ensure that the correct value parts were properly connected. Pay close attention to C9, a 0.05uF cap between the AVC line and B-. If this cap is not properly installed, you will get a "Motorboat" sound.

Disconnect the antenna and ensure that you are using the right pins on the antenna socket. One of the pins (Pin 2) connects to the speaker. Connecting the return of the antenna to that will generate all sorts of fun noises from feedback! Pin 4 goes to the stator of the RF Amp section of the tuning cap and pin 6 (grid) of the RF amp tube. Pin 1 goes to the AVC line through the 2.2 meg resistor R. However, I wonder if this is a mistake. On any other radio whose schematic I reviewed, the return of the loop antenna is directly to the AVC line (the frame of the tuning cap) and this 2.2 meg resistor does not exist. There is a 2.2 meg resistor between the detector output or AVC plate and the AVC line. This circuit develops a negative bias voltage depending on the strength of the signal. Try moving the connection to the stator and frame of the tuning cap.

Also, try to connect pin 3 (chassis ground) as per the instructions on the schematic. This may be necessary for stability, especially if you leave R1 in the circuit.

Check lead dress and position for all caps. A cap too far away from the chassis or too close to a tube socket could cause oscillation.

Hope this all helps.for all

With the antenna disconnected, connect a long wire (about 20 feet or so) to the stator of the Convertor section (likely the middle section) of the 3 gang tuning condenser. You should receive several stations with some normalcy. If hum or motor boating occurs, reinspect the AVC circuit. If good, touch the antenna to the stator of the RF section (Pin 4 of the antenna connector. Similar but better performance should occur.