There is a loud hum on this Philco 37-61 not affectd by the volume control. All the caps have been changed out, including the filter cps. A shielded cable has been installed from the 6q7 to the grid of the 6f6. A metal 6f6 has been tried. An .01 cap has been placed across the hot side of the 6f6 filament line to the chassis. I have fiddled with the hum-bucking coil and probably really didn't do anything with this futile exercise.
I have substituted a 5-watt resistor in place of the field coil and substituted a different speaker. The 5y4 has been substituted. An 80 with adapter for the 5y4 socket has been substituted.
I have taken all the other tubes out leaving only the 6f6 and 5y4 and still get the loud hum.
What have I overlooked?
I would be very grateful for any suggestions.
Many thanks.
Charlie

Hi Charlie

When you replaced the 8, 12 and 16 mfd filter caps did you notice the negative lead of the 12 mfd does not connect to ground? The old caps must also be disconnected and new ones can be slightly higher in value.

Norm

: There is a loud hum on this Philco 37-61 not affectd by the volume control. All the caps have been changed out, including the filter cps. A shielded cable has been installed from the 6q7 to the grid of the 6f6. A metal 6f6 has been tried. An .01 cap has been placed across the hot side of the 6f6 filament line to the chassis. I have fiddled with the hum-bucking coil and probably really didn't do anything with this futile exercise.
: I have substituted a 5-watt resistor in place of the field coil and substituted a different speaker. The 5y4 has been substituted. An 80 with adapter for the 5y4 socket has been substituted.
: I have taken all the other tubes out leaving only the 6f6 and 5y4 and still get the loud hum.
: What have I overlooked?
: I would be very grateful for any suggestions.
: Many thanks.
: Charlie

Aw, man, you are one genius. You cured my problem and
it was an easy fix.
Again, many thanks.
Charlie

: Hi Charlie

: When you replaced the 8, 12 and 16 mfd filter caps did you notice the negative lead of the 12 mfd does not connect to ground? The old caps must also be disconnected and new ones can be slightly higher in value.

: Norm

:
: : There is a loud hum on this Philco 37-61 not affectd by the volume control. All the caps have been changed out, including the filter cps. A shielded cable has been installed from the 6q7 to the grid of the 6f6. A metal 6f6 has been tried. An .01 cap has been placed across the hot side of the 6f6 filament line to the chassis. I have fiddled with the hum-bucking coil and probably really didn't do anything with this futile exercise.
: : I have substituted a 5-watt resistor in place of the field coil and substituted a different speaker. The 5y4 has been substituted. An 80 with adapter for the 5y4 socket has been substituted.
: : I have taken all the other tubes out leaving only the 6f6 and 5y4 and still get the loud hum.
: : What have I overlooked?
: : I would be very grateful for any suggestions.
: : Many thanks.
: : Charlie