Doess your radio/phonograph use a series filament circuit? If so does it use a 50X6 rectifier tube in the power supply (or another tube that has two diodes in it). If it does, the circuit may be what is called a voltage doubler circuit. You might check out a 46-1203 and see if your power supply circuit is similar to that one.
Radiodoc
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:I re-capped this neat phono-radio, resulting with the phono working fine, but when I switch to the radio side, I can tune stations, but have distorted reception with a background buzzing. Alignment is not the problem. I was very careful, and am sure I installed the power caps with the same polarity as what I replaced. My problem is that I cannot find a code 127 diagram. I need to be verify the resistors. It seems that Philco had several different circuits involved in a production run. The power circuit is strange in that I have a 16mfg cap that has a neg connection to the same post that has a pos connections from another 16mfg cap. I will appreciate any advice.
:Thanks,
:Bill B.
:Bill B.,
:
:Doess your radio/phonograph use a series filament circuit? If so does it use a 50X6 rectifier tube in the power supply (or another tube that has two diodes in it). If it does, the circuit may be what is called a voltage doubler circuit. You might check out a 46-1203 and see if your power supply circuit is similar to that one.
:
:Radiodoc
:**********
:
::I re-capped this neat phono-radio, resulting with the phono working fine, but when I switch to the radio side, I can tune stations, but have distorted reception with a background buzzing. Alignment is not the problem. I was very careful, and am sure I installed the power caps with the same polarity as what I replaced. My problem is that I cannot find a code 127 diagram. I need to be verify the resistors. It seems that Philco had several different circuits involved in a production run. The power circuit is strange in that I have a 16mfg cap that has a neg connection to the same post that has a pos connections from another 16mfg cap. I will appreciate any advice.
::Thanks,
::Bill B.
Recheck the electrolytic wiring. From your description, it sounds as though you have followed someone elses previous incorrect connections. The schematic does not indicate that such a connection should exist
Robert,
If the radio uses a full-wave voltage doubler (50Y6 contains two diode sections) then two caps will be stacked (connected in series so to speak) with a plus and minus connected together and one side of the AC line connected at the junction of the two. The plus of one cap of the combination goes to a cathode and the minus of the other cap goes to a plate of the 50Y5. The other plate and cathode are tied together and goes to the other AC line.
Radiodoc
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If the phono works fine (audio section I understand?) then it seems your radio suffers of tunable hum.
Check your rectifier as it was suggested in the previous reply. Or try bypassing the rectifier plate to ground using a .001uF. Also sometimes, a line bypass cap is necessary (they are usually around .05uF) and go from one side of the line to the chassis. Sometimes even two are used to create a fake isolated chassis on AC/DC sets.
Use Google (in "groups") and search for the terms "tunable hum". Sometimes a tube can be bad, but most of the time it is related to the power supply section.
Bill B.,
It is possible there is something that may be causing the buzzing from external to the radio such as fluorescent lights, light dimmers, computers, DVD players, battery chargers, wifi/wireless devices, TVs and etc. There are many devices today that can interfere with AM reception.
Radiodoc
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Good point.
But I presumed (wrongly ?) the OP has already checked that issue with another radio ? i.e. only that particular radio has that distortion and hum problem ?
::It is possible there is something that may be causing the buzzing from external to the radio such as fluorescent lights, light dimmers, computers, DVD players, battery chargers, wifi/wireless devices, TVs and etc. There are many devices today that can interfere with AM reception.
::
::Radiodoc
::**********
:
:Good point.
:
:But I presumed (wrongly ?) the OP has already checked that issue with another radio ? i.e. only that particular radio has that distortion and hum problem ?
If you would like, I could email you a couple of jpgs of a couple of pages that show a full-wave rectifier circuit with a bit of explanation of how it works. The jpegs are about 130KB each. Let me know.
Radiodoc
**********
:I re-capped this neat phono-radio, resulting with the phono working fine, but when I switch to the radio side, I can tune stations, but have distorted reception with a background buzzing. Alignment is not the problem. I was very careful, and am sure I installed the power caps with the same polarity as what I replaced. My problem is that I cannot find a code 127 diagram. I need to be verify the resistors. It seems that Philco had several different circuits involved in a production run. The power circuit is strange in that I have a 16mfg cap that has a neg connection to the same post that has a pos connections from another 16mfg cap. I will appreciate any advice.
:Thanks,
:Bill B.
Bill B.,
I should have said full-wave voltage doubler rectifier circuit.
Radiodoc
**********
:
::I re-capped this neat phono-radio, resulting with the phono working fine, but when I switch to the radio side, I can tune stations, but have distorted reception with a background buzzing. Alignment is not the problem. I was very careful, and am sure I installed the power caps with the same polarity as what I replaced. My problem is that I cannot find a code 127 diagram. I need to be verify the resistors. It seems that Philco had several different circuits involved in a production run. The power circuit is strange in that I have a 16mfg cap that has a neg connection to the same post that has a pos connections from another 16mfg cap. I will appreciate any advice.
::Thanks,
::Bill B.
The jpgs have been sent.
Radiodoc
**********
:::Bill B.,
:::
:::If you would like, I could email you a couple of jpgs of a couple of pages that show a full-wave rectifier circuit with a bit of explanation of how it works. The jpegs are about 130KB each. Let me know.
:::
:::Radiodoc
:::**********
::
::Bill B.,
::
::I should have said full-wave voltage doubler rectifier circuit.
::
::Radiodoc
::**********
:Yes, I would appreciate that info.
:::
::::I re-capped this neat phono-radio, resulting with the phono working fine, but when I switch to the radio side, I can tune stations, but have distorted reception with a background buzzing. Alignment is not the problem. I was very careful, and am sure I installed the power caps with the same polarity as what I replaced. My problem is that I cannot find a code 127 diagram. I need to be verify the resistors. It seems that Philco had several different circuits involved in a production run. The power circuit is strange in that I have a 16mfg cap that has a neg connection to the same post that has a pos connections from another 16mfg cap. I will appreciate any advice.
::::Thanks,
::::Bill B.