Carbon resistors go up in value over time. Although schematic doesn't show a value, 2 meg would be right.
Radiola 20 is a regen receiver. Be sure the regen control, amplification, is turned down. Turned up you will have oscillation & whistles.
Norm
:Greetings,
:Can anyone tell me the values of the grid leak resister and capacitor on the radiola 20? The one in it is red and measures 20+ megs. I tried 2 megs but get whistles and distortion. I would appreciate any input. Thanks.
:Hi Dan
:
: Carbon resistors go up in value over time. Although schematic doesn't show a value, 2 meg would be right.
:
: Radiola 20 is a regen receiver. Be sure the regen control, amplification, is turned down. Turned up you will have oscillation & whistles.
:
:Norm
:
::Greetings,
::Can anyone tell me the values of the grid leak resister and capacitor on the radiola 20? The one in it is red and measures 20+ megs. I tried 2 megs but get whistles and distortion. I would appreciate any input. Thanks.
Do you have "C" voltages connected? Your #20 tube should have -22 1/2 volts bias, others -4 1/2 volts. Is your #20 in the center position? Even though it's the output RCA wired it to the center socket.
B+ to the speaker 135 volts, 90 volts to others, except detector 45..
Check continuity of 2 audio interstage transformers. I've seen secondaries open with the radio still operating. If open, this will remove bias from the audio tubes.
Cap across grid leak resistor should be .00025 mfd. They are seldom bad.
Do you have the proper tubes? The radio was made for 4 - 99X's and a 20 tube. If you don't have these use 4 - 30's and a 31 with 2 volts for filament.
Norm
:Thanks Norm,
:I was trying to get better performance by changing the resister but havent noticed any improvement. Should the capacitor be .00025? I have distortion in the AF output. What do you think the cause might be?
:Thanks again for your help
:Dan
:
::Hi Dan
::
:: Carbon resistors go up in value over time. Although schematic doesn't show a value, 2 meg would be right.
::
:: Radiola 20 is a regen receiver. Be sure the regen control, amplification, is turned down. Turned up you will have oscillation & whistles.
::
::Norm
::
:::Greetings,
:::Can anyone tell me the values of the grid leak resister and capacitor on the radiola 20? The one in it is red and measures 20+ megs. I tried 2 megs but get whistles and distortion. I would appreciate any input. Thanks.
:Hi Dan
:
: Do you have "C" voltages connected? Your #20 tube should have -22 1/2 volts bias, others -4 1/2 volts. Is your #20 in the center position? Even though it's the output RCA wired it to the center socket.
:
: B+ to the speaker 135 volts, 90 volts to others, except detector 45..
:
: Check continuity of 2 audio interstage transformers. I've seen secondaries open with the radio still operating. If open, this will remove bias from the audio tubes.
:
: Cap across grid leak resistor should be .00025 mfd. They are seldom bad.
:
: Do you have the proper tubes? The radio was made for 4 - 99X's and a 20 tube. If you don't have these use 4 - 30's and a 31 with 2 volts for filament.
:
:Norm
:
:
::Thanks Norm,
::I was trying to get better performance by changing the resister but havent noticed any improvement. Should the capacitor be .00025? I have distortion in the AF output. What do you think the cause might be?
::Thanks again for your help
::Dan
::
:::Hi Dan
:::
::: Carbon resistors go up in value over time. Although schematic doesn't show a value, 2 meg would be right.
:::
::: Radiola 20 is a regen receiver. Be sure the regen control, amplification, is turned down. Turned up you will have oscillation & whistles.
:::
:::Norm
:::
::::Greetings,
::::Can anyone tell me the values of the grid leak resister and capacitor on the radiola 20? The one in it is red and measures 20+ megs. I tried 2 megs but get whistles and distortion. I would appreciate any input. Thanks.
Not knowing about your transistorized subs they may cause distortion and other problems? Usually Radiola 20's work well. Audio interstage transformers sometimes are open but that's about it.
Use 30's and 31 tubes if you don't already have 99's and a 20. They aren't original but work well with reduced filament voltage. Also less expensive.
Norm
:Thanks Norm,
:I'm using transistorized tubes because I'm afraid of accidentally distroying the x199's. I thought if I can get it working well with the transistors, I'll try the tubes later. Could the distortion come from too much gain in the transistors?
:
::Hi Dan
::
:: Do you have "C" voltages connected? Your #20 tube should have -22 1/2 volts bias, others -4 1/2 volts. Is your #20 in the center position? Even though it's the output RCA wired it to the center socket.
::
:: B+ to the speaker 135 volts, 90 volts to others, except detector 45..
::
:: Check continuity of 2 audio interstage transformers. I've seen secondaries open with the radio still operating. If open, this will remove bias from the audio tubes.
::
:: Cap across grid leak resistor should be .00025 mfd. They are seldom bad.
::
:: Do you have the proper tubes? The radio was made for 4 - 99X's and a 20 tube. If you don't have these use 4 - 30's and a 31 with 2 volts for filament.
::
::Norm
::
::
:::Thanks Norm,
:::I was trying to get better performance by changing the resister but havent noticed any improvement. Should the capacitor be .00025? I have distortion in the AF output. What do you think the cause might be?
:::Thanks again for your help
:::Dan
:::
::::Hi Dan
::::
:::: Carbon resistors go up in value over time. Although schematic doesn't show a value, 2 meg would be right.
::::
:::: Radiola 20 is a regen receiver. Be sure the regen control, amplification, is turned down. Turned up you will have oscillation & whistles.
::::
::::Norm
::::
:::::Greetings,
:::::Can anyone tell me the values of the grid leak resister and capacitor on the radiola 20? The one in it is red and measures 20+ megs. I tried 2 megs but get whistles and distortion. I would appreciate any input. Thanks.