I have previously posted on my radio volume going way down and distorting after the unit has been on for awhile. Thanks for all the replies. I have replaced the caps and most of the resistors. It was suggested to replace the resistor going to the 50B5 tube. I am prepared to do this, but I am confused. On the parts list and schematics, it lists an audio coupling unit that consists of 2 ceramic condesers and 2 carbon resistors. Is this the rectangular part that is connected to the pins of the 50B5 tube? If so, how do I go about replacing just the resistor parts? Thanks in advance for any help.

Steve

Hi Steve

The audio coupling unit might be an early printed circuit, PC-70? It has coupling caps and resistors inside.

Resistors that increase in value will give problems. You can parallel the grid resistor to see if there is improvement. Use 220K - 470K.

Measure voltage between pin #1 and #2 on your 50B5. Pin #1, grid, should be 5 to 7 volts negative. If it's not you will have distortion.

If you changed the coupling cap & resistor and voltage still goes down 50B5 is probably gassy/leaky.

Norm

:I have previously posted on my radio volume going way down and distorting after the unit has been on for awhile. Thanks for all the replies. I have replaced the caps and most of the resistors. It was suggested to replace the resistor going to the 50B5 tube. I am prepared to do this, but I am confused. On the parts list and schematics, it lists an audio coupling unit that consists of 2 ceramic condesers and 2 carbon resistors. Is this the rectangular part that is connected to the pins of the 50B5 tube? If so, how do I go about replacing just the resistor parts? Thanks in advance for any help.
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:Steve
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