The Model 80 is a four-tube superheterodyne with a regenerative second detector. Besides all new capacitors, the Model 80 sets like to have two resistors replaced for optimum performance: Part (9) and (11) on the schematic. Resistor (9) is a 9,000 ohm (9K) at 1 watt and resistor (11) is a 16,000 ohm (16K) at 3 watts. The 16K resistor is especially prone to increasing in value to a point that adversely affects the set’s performance.
After re-capping, the only precaution you need to take is with the regeneration (Sensitivity) trimmer condenser, part (18) on the schematic. After alignment, the set should be tuned to a strong local AM station, preferably at the upper end of the AM band. The Sensitivity condenser, which has a long fiber shaft, should then be turned clockwise until the set breaks into oscillation (squeals). Back off the adjustment until the oscillation stops, then turn the condenser counter-clockwise 1/4 turn. Check the reception across the band. If you have any more oscillation, back the adjustment off another 1/4 turn. The point is to have the set operating close to the oscillating point without going over, for best reception.
By Ron Ramirez (09/96, R+P Newsgroup message thread.)