You mention "hum along with station sound". Does that mean you receive radio stations along with hum?

If hum is there in phono position problem is in band switching (S1) or grounding.

The jumper the Edd mentioned should have stopped hum from the phonograph.

Norm

If it's there in radio position still could be early stages of the radio. Cathode to filament leakage in 12BA6 or 12BE6 tubes.

:I checked the loop antenna and think it is hooked up OK. Also, earlier tried another 50L6 and didn't help. On AC my meter shows 12V of hum at the 33ohm resistor off one filter but have changed out that filter section and no difference.
:
:
::
::

:: :: :: :: :: :: :: :: :: :: :: :: ::Sir Joe . . . . . . :: :: ::Phase 2: :: :: ::Hmmmm . . then, that's too far forward in the circiutry , how about now moving to the 1st grid of the 50L6 and jumpering across its 1st grid resistor ( 470 K) for just a couple of seconds to evaluate . :: :: ::If stil humMMMMMing . . . then U might suspect a possibly bad 50L6. :: ::As per the loop antenna, usually if it is open, but yet capable of receiving a strong station, it will add a louder "underwater' warbling intonation to the reproduced audio. :: :: :: :: :: :: :: ::73's de Edd :: :: :: :: ::

::
::
::
::
::
::
::
::
::
::
::
::
::
:::John
:::
::: It's not filter caps if hum is gone with volume turned down.
:::
::: Do you have the loop antenna connected? It needs to be connected to complete the grid circuit of 12BE6 tube. Without it there will be hum.
:::
:::Norm
:::
::::The jumper did nothing. Still lots of hum.
::::
::::
::::
:::::
:::::

::::: ::::: ::::: ::::: ::::: ::::: ::::: ::::: ::::: ::::: :::::Sir John . . . . . . ::::: ::::: :::::Hmmmm . . Hows about the possibility of poor grounding or a record player fallacy, since it is occuring prior to the volume control circuitry and the power supply seems to not be involved. ::::: ::::: ::::: :::::Troubleshooting . . . Phase 1 : ::::: ::::: :::::Try placing a jumper lead across the ends of the components of the [ RED ] mark up as is shown below and see what happens. ::::: ::::: ::::: ::::: ::::: ::::: ::::: :::::73's de Edd ::::: ::::: ::::: ::::: :::::

:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
::::::My RCA 9Y51 radio/player has hum along with station sound when I turn the volume up. No hum at zero volume. Checked and replaced defective tubes but no difference. Jumped out filter caps but no difference.
::::::
:::::
::::
:::
::
:

:John
:
: You mention "hum along with station sound". Does that mean you receive radio stations along with hum?
:
: If hum is there in phono position problem is in band switching (S1) or grounding.
:
: The jumper the Edd mentioned should have stopped hum from the phonograph.
:
:Norm
:
: If it's there in radio position still could be early stages of the radio. Cathode to filament leakage in 12BA6 or 12BE6 tubes.
:
::I checked the loop antenna and think it is hooked up OK. Also, earlier tried another 50L6 and didn't help. On AC my meter shows 12V of hum at the 33ohm resistor off one filter but have changed out that filter section and no difference.
::
::
:::
:::

::: ::: ::: ::: ::: ::: ::: ::: ::: ::: ::: ::: :::Sir Joe . . . . . . ::: ::: :::Phase 2: ::: ::: :::Hmmmm . . then, that's too far forward in the circiutry , how about now moving to the 1st grid of the 50L6 and jumpering across its 1st grid resistor ( 470 K) for just a couple of seconds to evaluate . ::: ::: :::If stil humMMMMMing . . . then U might suspect a possibly bad 50L6. ::: :::As per the loop antenna, usually if it is open, but yet capable of receiving a strong station, it will add a louder "underwater' warbling intonation to the reproduced audio. ::: ::: ::: ::: ::: ::: ::: :::73's de Edd ::: ::: ::: ::: :::

:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
::::John
::::
:::: It's not filter caps if hum is gone with volume turned down.
::::
:::: Do you have the loop antenna connected? It needs to be connected to complete the grid circuit of 12BE6 tube. Without it there will be hum.
::::
::::Norm
::::
:::::The jumper did nothing. Still lots of hum.
:::::
:::::
:::::
::::::
::::::

:::::: :::::: :::::: :::::: :::::: :::::: :::::: :::::: :::::: :::::: ::::::Sir John . . . . . . :::::: :::::: ::::::Hmmmm . . Hows about the possibility of poor grounding or a record player fallacy, since it is occuring prior to the volume control circuitry and the power supply seems to not be involved. :::::: :::::: :::::: ::::::Troubleshooting . . . Phase 1 : :::::: :::::: ::::::Try placing a jumper lead across the ends of the components of the [ RED ] mark up as is shown below and see what happens. :::::: :::::: :::::: :::::: :::::: :::::: :::::: ::::::73's de Edd :::::: :::::: :::::: :::::: ::::::

::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
:::::::My RCA 9Y51 radio/player has hum along with station sound when I turn the volume up. No hum at zero volume. Checked and replaced defective tubes but no difference. Jumped out filter caps but no difference.
:::::::
::::::
:::::
::::
:::
::
:

:Yes, get hum along with station sound. I can ground pin 5 on the 12AV6 and still have hum, no difference. If I ground pin 1 then the hum almost all goes away. Haven't tried to see if there is hum in the phono position yet.
:
:
:
::John
::
:: You mention "hum along with station sound". Does that mean you receive radio stations along with hum?
::
:: If hum is there in phono position problem is in band switching (S1) or grounding.
::
:: The jumper the Edd mentioned should have stopped hum from the phonograph.
::
::Norm
::
:: If it's there in radio position still could be early stages of the radio. Cathode to filament leakage in 12BA6 or 12BE6 tubes.
::
:::I checked the loop antenna and think it is hooked up OK. Also, earlier tried another 50L6 and didn't help. On AC my meter shows 12V of hum at the 33ohm resistor off one filter but have changed out that filter section and no difference.
:::
:::
::::
::::

:::: :::: :::: :::: :::: :::: :::: :::: :::: :::: :::: :::: ::::Sir Joe . . . . . . :::: :::: ::::Phase 2: :::: :::: ::::Hmmmm . . then, that's too far forward in the circiutry , how about now moving to the 1st grid of the 50L6 and jumpering across its 1st grid resistor ( 470 K) for just a couple of seconds to evaluate . :::: :::: ::::If stil humMMMMMing . . . then U might suspect a possibly bad 50L6. :::: ::::As per the loop antenna, usually if it is open, but yet capable of receiving a strong station, it will add a louder "underwater' warbling intonation to the reproduced audio. :::: :::: :::: :::: :::: :::: :::: ::::73's de Edd :::: :::: :::: :::: ::::

::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
:::::John
:::::
::::: It's not filter caps if hum is gone with volume turned down.
:::::
::::: Do you have the loop antenna connected? It needs to be connected to complete the grid circuit of 12BE6 tube. Without it there will be hum.
:::::
:::::Norm
:::::
::::::The jumper did nothing. Still lots of hum.
::::::
::::::
::::::
:::::::
:::::::

::::::: ::::::: ::::::: ::::::: ::::::: ::::::: ::::::: ::::::: ::::::: ::::::: :::::::Sir John . . . . . . ::::::: ::::::: :::::::Hmmmm . . Hows about the possibility of poor grounding or a record player fallacy, since it is occuring prior to the volume control circuitry and the power supply seems to not be involved. ::::::: ::::::: ::::::: :::::::Troubleshooting . . . Phase 1 : ::::::: ::::::: :::::::Try placing a jumper lead across the ends of the components of the [ RED ] mark up as is shown below and see what happens. ::::::: ::::::: ::::::: ::::::: ::::::: ::::::: ::::::: :::::::73's de Edd ::::::: ::::::: ::::::: ::::::: :::::::

:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
::::::::My RCA 9Y51 radio/player has hum along with station sound when I turn the volume up. No hum at zero volume. Checked and replaced defective tubes but no difference. Jumped out filter caps but no difference.
::::::::
:::::::
::::::
:::::
::::
:::
::
:

Pin #1 is grid of 1st audio amp. Problem must be before that point. Schematic that Edd posted shows shielded wire connected to center of the volume control. Is the shield grounded?

There are other shielded wires to S1. Are these shields grounded? If not there will be hum.

Norm

:Yes, still get loud hum in phono position. So it must be coming from the switch, S1. So How can that be cured? Or can't it?
:
::Yes, get hum along with station sound. I can ground pin 5 on the 12AV6 and still have hum, no difference. If I ground pin 1 then the hum almost all goes away. Haven't tried to see if there is hum in the phono position yet.
::
::
::
:::John
:::
::: You mention "hum along with station sound". Does that mean you receive radio stations along with hum?
:::
::: If hum is there in phono position problem is in band switching (S1) or grounding.
:::
::: The jumper the Edd mentioned should have stopped hum from the phonograph.
:::
:::Norm
:::
::: If it's there in radio position still could be early stages of the radio. Cathode to filament leakage in 12BA6 or 12BE6 tubes.
:::
::::I checked the loop antenna and think it is hooked up OK. Also, earlier tried another 50L6 and didn't help. On AC my meter shows 12V of hum at the 33ohm resistor off one filter but have changed out that filter section and no difference.
::::
::::
:::::
:::::

::::: ::::: ::::: ::::: ::::: ::::: ::::: ::::: ::::: ::::: ::::: ::::: :::::Sir Joe . . . . . . ::::: ::::: :::::Phase 2: ::::: ::::: :::::Hmmmm . . then, that's too far forward in the circiutry , how about now moving to the 1st grid of the 50L6 and jumpering across its 1st grid resistor ( 470 K) for just a couple of seconds to evaluate . ::::: ::::: :::::If stil humMMMMMing . . . then U might suspect a possibly bad 50L6. ::::: :::::As per the loop antenna, usually if it is open, but yet capable of receiving a strong station, it will add a louder "underwater' warbling intonation to the reproduced audio. ::::: ::::: ::::: ::::: ::::: ::::: ::::: :::::73's de Edd ::::: ::::: ::::: ::::: :::::

:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
::::::John
::::::
:::::: It's not filter caps if hum is gone with volume turned down.
::::::
:::::: Do you have the loop antenna connected? It needs to be connected to complete the grid circuit of 12BE6 tube. Without it there will be hum.
::::::
::::::Norm
::::::
:::::::The jumper did nothing. Still lots of hum.
:::::::
:::::::
:::::::
::::::::
::::::::

:::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: ::::::::Sir John . . . . . . :::::::: :::::::: ::::::::Hmmmm . . Hows about the possibility of poor grounding or a record player fallacy, since it is occuring prior to the volume control circuitry and the power supply seems to not be involved. :::::::: :::::::: :::::::: ::::::::Troubleshooting . . . Phase 1 : :::::::: :::::::: ::::::::Try placing a jumper lead across the ends of the components of the [ RED ] mark up as is shown below and see what happens. :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: ::::::::73's de Edd :::::::: :::::::: :::::::: :::::::: ::::::::

::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
:::::::::My RCA 9Y51 radio/player has hum along with station sound when I turn the volume up. No hum at zero volume. Checked and replaced defective tubes but no difference. Jumped out filter caps but no difference.
:::::::::
::::::::
:::::::
::::::
:::::
::::
:::
::
: