This is an improved version of the original Model 10 “breadboard AM radio. The changes from the earlier version include eliminating the potentiometer that controlled RF amplifier grid bias and replacing it with an 800 Ohm damper resistor, and eliminating the bypass capacitors on the RF amplifier filaments.
The set uses two 201A tubes for the Radio Frequency section, a 200 tube for the Detector, and two 201A tubes for the Audio Amplifier. We could use a 200A tube with a thoriated tungsten filament for the Detector and reduce the total filament current by 0.75A. These were common tubes, so we should have plenty in the Museum’s inventory.
This radio is currently in the Wireless Workshop being restored. We need to completely disassemble the radio so we can clean the finish on the breadboard. The original finish is in good condition, so there is no need to replace it. The rubber washers on the fine tuning knobs will need to be replaced because they harden with age and will not turn the dial. We need to check the condition of the resistors, capacitors, inductors, and especially the transformers in the compartment at the right. This breadboard has mounting holes in the four corners. We have been told that it was likely built to be mounted inside of a cabinet made by Pooley Company in Philadelphia, PA. On this breadboard the power cord is attached to the bottom. This is another clue that this breadboard was intended to be mounted in a cabinet. We will also need to restore or make a Battery Eliminator to supply the +90VDC, +22.5VDC, and +6VDC to power the radio.