The 2K resistor should work ok (will have to increase the capacity of the electrolytics to maybe 20mfd or so to reduce hum). If the electrolytic(s) C8 & C9 have never been replaced, will probably be leaky and cause the 2K resistor to heat up. Note the negative of C9 goes to the centertap of the transformer high voltage winding and not chassis/ground. Also if none of the wax/paper capacitors have been replaced probably will have to replace them starting with C5,C7 and C10.
The schematic diagram is at: http://www.nostalgiaair.org/PagesByModel/566/M0011566.pdf
Clifton
:Hi all!!! I have a Airline model 62-476 that once had a 2000 ohm speaker field coil...Someone before me replaced speaker with a modern type and used a resistor in place of the field coil..Soooooooo now radio sounds bad and I have a resistor that gets to hot... I thought of using a choke but space is VERY limmited...any ideas? Would like to find a speaker with a 2000 ohm field coil to put back in place..OR????? Thanks for your thoughts and suggestions
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If you used a choke, I don't think it has to be on the radio. The choke or choke-resistor combination could be mounted at the PM speaker. The reason for the larger caps is that a resistor doesn't have the same filtering capability as a choke or speaker field does. You can use a choke with lesser resistance and make up for the rest with a resistor and still get good filtering.
Clifton
:Cliff i did a complete recap..but have electro. caps at 5 and 5 at 450 as schematic calls for ..I will bump up to 10 and 10 at 450...
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As a reminder again, make sure C9, I think it is, has it's minus lead connected to the high voltage winding centertap and not chassis/ground. Also, if the old dual cap is still in place, make sure it is completely disconnected from the circuitry. A bad practice in the past was to bridge an electrolytic cap that had lost capacity with a good one leaving the old one still connected.
Clifton
:George,
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:If you used a choke, I don't think it has to be on the radio. The choke or choke-resistor combination could be mounted at the PM speaker. The reason for the larger caps is that a resistor doesn't have the same filtering capability as a choke or speaker field does. You can use a choke with lesser resistance and make up for the rest with a resistor and still get good filtering.
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:Clifton
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::Cliff i did a complete recap..but have electro. caps at 5 and 5 at 450 as schematic calls for ..I will bump up to 10 and 10 at 450...
::
:
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I don't think you mentioned if there was considerable power supply hum or not. Generally if you replace a choke or speaker field choke with a resistor, you will have to up the filter capacitors a bit to reduce the hum.
Clifton
:The original schematic calls for 2 5 mf elct. caps but since I no longer have a 2000 ohm field coil on speaker (replaced w/ resistor) Would as you mentioned (Cliff) bumping the two caps up to 20mf..would that be to much or even better for filtering...???
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You could probably use a salvaged output transformer primary and see how it works used as a choke. You can make up the difference in resistance with a resistor. As I understand it, in the early years of radio there was a lot of experimenting.
Clifton
:Is it possible or ok to use just one side of a small transformer say 500 or 1000 ohm winding and make up rest (2000) with a resistor..using only one side of the transformer as a choke ..I have one that has windings at 1000 ohms.... ..Would that work??
:::I don't think you mentioned if there was considerable power supply hum or not. Generally if you replace a choke or speaker field choke with a resistor, you will have to up the filter capacitors a bit to reduce the hum.
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::Clifton
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:::The original schematic calls for 2 5 mf elct. caps but since I no longer have a 2000 ohm field coil on speaker (replaced w/ resistor) Would as you mentioned (Cliff) bumping the two caps up to 20mf..would that be to much or even better for filtering...???
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All the Best,
Bill
;-)