I just recapped (Including the filters) a Philco 40-115 table radio. I still have a hum in the sound. I replaced the filters a second time with a higher value and still have the hum. If I turn the volume up almost all the way, the hum goes away. I am guessing maybe a bad pot.

It looks like the radio was repaired a long time ago. A choke has been replaced with wire wrapped around a cap. I have replaced the wire and played around with the choke and nothing changed. Any ideas?

Hi,
Have you tried any contact cleaner/lube like LPS1 on the volume control? Have you checked for a cold solder joint? corroded tube pins or socket? Is any tube "microphonic" (makes a lot of noise when tapped)? Are the band switch contacts clean? Is the speaker the original field coil type, or did that get replaced with a permanent magnet type? If it was the latter, try putting a 300 ohm 22 to 25 Watt resistor where the original field coil was. If you still have the original field coil, leave that area alone.

I am assuming that the caps you put in were connected exactly as the ones that were in there were connected, and this is fine, but if the fellow who worked on it before you had connected something to the wrong spot, that could very well be the source of all of the problems. If you have the schematic, compare each item you replaced with what the schematic shows, then if there are any remaining repairs from someone else, compare those to the schematic too. If you do not have the schematic, it will be here on this site, just go to the button at the top of the page for "resources", and scroll down to Philco, then scroll down that page to your model.

:I just recapped (Including the filters) a Philco 40-115 table radio. I still have a hum in the sound. I replaced the filters a second time with a higher value and still have the hum. If I turn the volume up almost all the way, the hum goes away. I am guessing maybe a bad pot.
:
:It looks like the radio was repaired a long time ago. A choke has been replaced with wire wrapped around a cap. I have replaced the wire and played around with the choke and nothing changed. Any ideas?

Typically, if there is a hum that goes away when the volume control is turned almost all the way up, this is due to either a faulty ground connection to the low end of the pot or a fault pot. Sometimes, too, when people try the WD-40 trick and saturate the pot with WD-40, this causes traces of carbon to form a path to the pot case. This will allow interferance (hum) to get into this circuit.

T.D.

:Typically, if there is a hum that goes away when the volume control is turned almost all the way up, this is due to either a faulty ground connection to the low end of the pot or a fault pot. Sometimes, too, when people try the WD-40 trick and saturate the pot with WD-40, this causes traces of carbon to form a path to the pot case. This will allow interferance (hum) to get into this circuit.
:
:T.D.

::Typically, if there is a hum that goes away when the volume control is turned almost all the way up, this is due to either a faulty ground connection to the low end of the pot or a fault pot. Sometimes, too, when people try the WD-40 trick and saturate the pot with WD-40, this causes traces of carbon to form a path to the pot case. This will allow interferance (hum) to get into this circuit.
::
::T.D.

Thanks T. D. You were right it was a bad pot. replaced it and now sounds great. LD