I just recapped my first antique radio a philco model 38-7 121 chassis. The radio volume is low on th AM band unless I touch the side of the 6A8 tube with has been replaced with a short metal housing type tube.
The radio works good on SW band. Can anyone tell me how to correct this?

Thanks, Terry

The 38-7 Used glass tubes so the metal 6A8 is not properly grounded. Pin #1 of the tube socket was usually used for metal tube ground. Sometimes, with glass tubes, pin #1 is used as tie point for other components. You are inducing a signal though the ungrounded tube shield. It is kind of like being your own antenna. You may have a defective antenna coil or a dirty bandswitch. Try cleaning the bandswitch with CRC non residual contact cleaner and the seal the contacts with a slight amount of dielectric grease. Do not use WD-40. Do not soak the coils or the trimmer capacitors with the dielectric grease as it may detune them. Other may have more detailed info.

MRO

:I just recapped my first antique radio a philco model 38-7 121 chassis. The radio volume is low on th AM band unless I touch the side of the 6A8 tube with has been replaced with a short metal housing type tube.
:The radio works good on SW band. Can anyone tell me how to correct this?
:
:Thanks, Terry

Hi

Mark has a good point. Philco never used metal tubes in their radios. Metal tubes were an RCA idea. If you have a Philco radio with metal tubes they are replacements. Philco did sell metal tubes with their name for replacement in other radios.

Norm

:The 38-7 Used glass tubes so the metal 6A8 is not properly grounded. Pin #1 of the tube socket was usually used for metal tube ground. Sometimes, with glass tubes, pin #1 is used as tie point for other components. You are inducing a signal though the ungrounded tube shield. It is kind of like being your own antenna. You may have a defective antenna coil or a dirty bandswitch. Try cleaning the bandswitch with CRC non residual contact cleaner and the seal the contacts with a slight amount of dielectric grease. Do not use WD-40. Do not soak the coils or the trimmer capacitors with the dielectric grease as it may detune them. Other may have more detailed info.
:
:MRO
:
::I just recapped my first antique radio a philco model 38-7 121 chassis. The radio volume is low on th AM band unless I touch the side of the 6A8 tube with has been replaced with a short metal housing type tube.
::The radio works good on SW band. Can anyone tell me how to correct this?
::
::Thanks, Terry

Just another thought. My 38-7 is real finicky about the 6K7 tube. Some 6K7's that test fine (and work in other radios) do not work in mine. just a possibility,
John

:Hi
:
: Mark has a good point. Philco never used metal tubes in their radios. Metal tubes were an RCA idea. If you have a Philco radio with metal tubes they are replacements. Philco did sell metal tubes with their name for replacement in other radios.
:
: Norm
:
:
::The 38-7 Used glass tubes so the metal 6A8 is not properly grounded. Pin #1 of the tube socket was usually used for metal tube ground. Sometimes, with glass tubes, pin #1 is used as tie point for other components. You are inducing a signal though the ungrounded tube shield. It is kind of like being your own antenna. You may have a defective antenna coil or a dirty bandswitch. Try cleaning the bandswitch with CRC non residual contact cleaner and the seal the contacts with a slight amount of dielectric grease. Do not use WD-40. Do not soak the coils or the trimmer capacitors with the dielectric grease as it may detune them. Other may have more detailed info.
::
::MRO
::
:::I just recapped my first antique radio a philco model 38-7 121 chassis. The radio volume is low on th AM band unless I touch the side of the 6A8 tube with has been replaced with a short metal housing type tube.
:::The radio works good on SW band. Can anyone tell me how to correct this?
:::
:::Thanks, Terry

Thanks for all the help. I am going to order glass tubes to replace this one and 6f6g as it is also metal in my set.
Terry

:Just another thought. My 38-7 is real finicky about the 6K7 tube. Some 6K7's that test fine (and work in other radios) do not work in mine. just a possibility,
:John
:
::Hi
::
:: Mark has a good point. Philco never used metal tubes in their radios. Metal tubes were an RCA idea. If you have a Philco radio with metal tubes they are replacements. Philco did sell metal tubes with their name for replacement in other radios.
::
:: Norm
::
::
:::The 38-7 Used glass tubes so the metal 6A8 is not properly grounded. Pin #1 of the tube socket was usually used for metal tube ground. Sometimes, with glass tubes, pin #1 is used as tie point for other components. You are inducing a signal though the ungrounded tube shield. It is kind of like being your own antenna. You may have a defective antenna coil or a dirty bandswitch. Try cleaning the bandswitch with CRC non residual contact cleaner and the seal the contacts with a slight amount of dielectric grease. Do not use WD-40. Do not soak the coils or the trimmer capacitors with the dielectric grease as it may detune them. Other may have more detailed info.
:::
:::MRO
:::
::::I just recapped my first antique radio a philco model 38-7 121 chassis. The radio volume is low on th AM band unless I touch the side of the 6A8 tube with has been replaced with a short metal housing type tube.
::::The radio works good on SW band. Can anyone tell me how to correct this?
::::
::::Thanks, Terry