Hi,I finished up recapping my Philco 77. All excited I fired it up. No volume until I touched the volume control shaft, top of the 1st rf tube (24), or the coil #5. Checked coil resistance 6.2 ohms from cap of 24 to gnd. matches other coils, antenna coil ok, rf coils ok, B+ on plates of RF tubes with in specs, volume control pod, ground connections, and voltages, all look ok. Ran a jumper from 24 cap connection on coil to ant. got a little better, but not as good as if you touch it. Some stations you can hear faintly, but others not until you touch. Tried swapping tubes, no difference. Probably something simple staring me in the face. Frustration got the best of me at this point. Any and all ideas welcomed. Thanks ahead of time, Richard

:Hi,I finished up recapping my Philco 77. All excited I fired it up. No volume until I touched the volume control shaft, top of the 1st rf tube (24), or the coil #5. Checked coil resistance 6.2 ohms from cap of 24 to gnd. matches other coils, antenna coil ok, rf coils ok, B+ on plates of RF tubes with in specs, volume control pod, ground connections, and voltages, all look ok. Ran a jumper from 24 cap connection on coil to ant. got a little better, but not as good as if you touch it. Some stations you can hear faintly, but others not until you touch. Tried swapping tubes, no difference. Probably something simple staring me in the face. Frustration got the best of me at this point. Any and all ideas welcomed. Thanks ahead of time, Richard

Hi Richard,

Have you checked the 'volume control' resistance from the antenna terminal to ground? To keep from measuring the coil resistance, I would remove the wire going to the coil from the control center terminal. Now, one dumb question. Do you have an antenna connected to the antenna terminal, say up to 30 feet in length? An antenna will have to be connected.

Radiodoc

I agree check the volume control. It is a two section control, according to the schematic, and one part of it is going directly to the antenna. Does the volume increase if you touch the 1st section tuning capacitor lug?
MRO

Well, like Doc and Mark have said, the problem must be in the ckt between the antenna and the grid of the 1st RF stage. I'd first suspect the antenna coil, but you say you checked that.

Go over that front end with a fine-toothed comb, checking continuity, values, etc.

You reported that the volume goes up when you touch the "Coil #5." If I'm reading the schematic correctly, #5 is a cap -- did you mean the Antenna Coil, #2?

:Well, like Doc and Mark have said, the problem must be in the ckt between the antenna and the grid of the 1st RF stage. I'd first suspect the antenna coil, but you say you checked that.
:
:Go over that front end with a fine-toothed comb, checking continuity, values, etc.
:
:You reported that the volume goes up when you touch the "Coil #5." If I'm reading the schematic correctly, #5 is a cap -- did you mean the Antenna Coil, #2?
:
:Thanks for the answers, I do not have that long of an antenna it is about 15 feet. It works well for my Philco 87. I disconnected coil #2 one side 6.2ohms, the other 21.3ohms and #5 center lug to ether outer lug 6.1ohms, outer lugs cont. but; they look like they are connected together with in two coil turns. I do not know what the exact specs they are suppose to be I just know they are not open and are not shorted together. Resistance between ant. & gnd. ranges from 22ohms to 5.2k ohms. and is smooth from stop to stop. Yes if I touch front tuning capacitor lug it does get louder also the cap of the first RF tube. Thanks, Richard

::Well, like Doc and Mark have said, the problem must be in the ckt between the antenna and the grid of the 1st RF stage. I'd first suspect the antenna coil, but you say you checked that.
::
::Go over that front end with a fine-toothed comb, checking continuity, values, etc.
::
::You reported that the volume goes up when you touch the "Coil #5." If I'm reading the schematic correctly, #5 is a cap -- did you mean the Antenna Coil, #2?
::
::Thanks for the answers, I do not have that long of an antenna it is about 15 feet. It works well for my Philco 87. I disconnected coil #2 one side 6.2ohms, the other 21.3ohms and #5 center lug to ether outer lug 6.1ohms, outer lugs cont. but; they look like they are connected together with in two coil turns. I do not know what the exact specs they are suppose to be I just know they are not open and are not shorted together. Resistance between ant. & gnd. ranges from 22ohms to 5.2k ohms. and is smooth from stop to stop. Yes if I touch front tuning capacitor lug it does get louder also the cap of the first RF tube. Thanks, Richard

Hey Guys,

Could it possibly be something as simple as adjusting the compensating condensers as outlined on the page with the schematic?

Radiodoc