I am trying to get a Philco farm radio playing. The resistor value for the voltage to pin 5 of the 1LA6 is 37 v. Resistor to drop it to that is 68 K. When used 2 33k in series I get about 30 v. to tube.. Will have to keep trying other values of resistors to get that 37 v. NOW QUESTION how close to that 37 v. do I need to be, could 1 or2 below or above work? Oh I see I left out the model #. It a 46-132

Jim,

If you have a spare potentiometer (volume control) around of about 100K to 200K, you can use clip leads and insert it in the place of the unknown resistor (center terminal and one outside terminal). Adjust until you get the voltage you want on pin 5. Remove the clip leads from the circuit and measure the resistance and use a standard value resistor closest to what the potentiometer measured.

Radiodoc
*******************

:I am trying to get a Philco farm radio playing. The resistor value for the voltage to pin 5 of the 1LA6 is 37 v. Resistor to drop it to that is 68 K. When used 2 33k in series I get about 30 v. to tube.. Will have to keep trying other values of resistors to get that 37 v. NOW QUESTION how close to that 37 v. do I need to be, could 1 or2 below or above work? Oh I see I left out the model #. It a 46-132
:

:Jim,
:
:If you have a spare potentiometer (volume control) around of about 100K to 200K, you can use clip leads and insert it in the place of the unknown resistor (center terminal and one outside terminal). Adjust until you get the voltage you want on pin 5. Remove the clip leads from the circuit and measure the resistance and use a standard value resistor closest to what the potentiometer measured.
:
:Radiodoc
:*******************

I always was told the limits were +/- 20%. Of course, I wouldn't run something at the limit, but maybe +/- ten percent?
Lewis

:
:
::I am trying to get a Philco farm radio playing. The resistor value for the voltage to pin 5 of the 1LA6 is 37 v. Resistor to drop it to that is 68 K. When used 2 33k in series I get about 30 v. to tube.. Will have to keep trying other values of resistors to get that 37 v. NOW QUESTION how close to that 37 v. do I need to be, could 1 or2 below or above work? Oh I see I left out the model #. It a 46-132
::
:

::Jim,
::
::If you have a spare potentiometer (volume control) around of about 100K to 200K, you can use clip leads and insert it in the place of the unknown resistor (center terminal and one outside terminal). Adjust until you get the voltage you want on pin 5. Remove the clip leads from the circuit and measure the resistance and use a standard value resistor closest to what the potent
::
::Radiodoc
::*******************
:
:
:
:
:I always was told the limits were +/- 20%. Of course, I wouldn't run something at the limit, but maybe +/- ten percent?
:Lewis
:
:
:
::
::
:::I am trying to get a Philco farm radio playing. The resistor value for the voltage to pin 5 of the 1LA6 is 37 v. Resistor to drop it to that is 68 K. When used 2 33k in series I get about 30 v. to tube.. Will have to keep trying other values of resistors to get that 37 v. NOW QUESTION how close to that 37 v. do I need to be, could 1 or2 below or above work? Oh I see I left out the model #. It a 46-132
:::
::
Thanks guys will let u know results