07-26-2014, 06:15 PM
Hi Mike, and welcome to the forum. I have a 48-482 and have been working on restoration of mine on and off for some time. I think you will find that you will also will have to replace many off tolerance resistors.
One resistor in particular that may be causing your low FM sensitivity is R502, which is the plate load resistor of the 7W7 FM RF amp tube. This 33K resistor dissipates more than the rated wattage in circuit and invariably rises in value. It was completely open in my set and prevented the RF stage from operating, resulting in low sensitivity.
If you are going to change paper caps, check and replace off tolerance resistors at the same time and save some extra work.
One resistor in particular that may be causing your low FM sensitivity is R502, which is the plate load resistor of the 7W7 FM RF amp tube. This 33K resistor dissipates more than the rated wattage in circuit and invariably rises in value. It was completely open in my set and prevented the RF stage from operating, resulting in low sensitivity.
If you are going to change paper caps, check and replace off tolerance resistors at the same time and save some extra work.
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