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Burned resistor
1/19/2009 10:28:05 AMDave
Have a Motorola 40-60W with a burned resistor. I can not read the value from the schematics. It goes from pin 8 of the 35L6 to pin 8 of the 12SQ7.

Thanks

1/19/2009 11:04:14 AMLewis L
:Have a Motorola 40-60W with a burned resistor. I can not read the value from the schematics. It goes from pin 8 of the 35L6 to pin 8 of the 12SQ7.
:
:Thanks

That looks like the cathode resistor for the 35L6, going to ground. Looks like 200 Ohm to me, can't tell the Wattage.
Lewis
:

1/19/2009 6:48:03 PMThomas Dermody
In most radios the wattage was 1/2. You can use a 1 watt. Also, in most radios the 35/50L6 cathode bias resistor is 150 ohms. 200 was used in some. If I had a graph, I could tell you which way was more class A and which was more class B. At any rate, changing from one value to another changes the grid bias point. Use the value you prefer to listen with.

Before replacing the resistor, check the tube for gas, and check the control grid cap for leakage (best to just replace for reliability's sake). If the grid cap is leaky or the tube is gassy, it'll conduct excessively. Also be sure that the grid leak resistor hasn't drifted.

T.



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