Hallicrafters S120 hum at no vol and hum with volume

[tubetwister]

Originally Posted by Electronic M

When you say last and first tubes in the string that is rather vague...Better to refer to them by their functions: converter(AKA 1st detector), IF, Second detector/AVC/1st audio, audio output (at least that is what the line up would usually consist of in an average selenium powered AA4).

Do you have any clip leads (that have small alligator clips on both ends)?

EDIT 08.15.2017
Yes and more and lots of solid state ( SS experience ) note my education futher down


Noting you must let ALL the tube heats cool B4 next power up lest you fry a tube or are stupid and lucky but the rest of it is 4 + decades OLD NEWS but the AA5 radio back then had bad LYITCS as I suspected the reason > AC hum much Much LOUDER than this RaDiO !

This hum is forward of of the DUAL TRIODE FIRST AUDIO /AVC 12AT7 PARALLEL WIRED DIODE PLATES or maybe 1st audio cntrl.grid if you happen to know what all that is


FWIW I was reading tube DATA and building projects (transformer powred ofc) out of RCA tube manual ref. designs we all used 4 decades before you were conceived & later getting proper EDUCATION

I dont mean a vocational certificate diploma mill or High school but >>>>>> Electronics and Solid State Engineering study but not tube radios there LOL .......maybe NIXI tubes on some counters or just to make something red hot explode or melt for a prank or some lessons but not many


TBH I was humoring you
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4 NOS tubes and circt. parts arriving soon may fix all this while your sig trce Detector diode idea is very good and detailed
I am too to lazy ti gin up a proper circuit trace jimmy rig in an Altoids Tin ,with a diode DETECTOR probe capacitor uF like you say that can discern an AC hum ,an OP amp, a battery and buffer caps & whatever for a Ti PDIP- 8 op amp .


I have it covered note my edu. and now that I spent some-refresh- tine with the schematics ...I can read these old crude AA4-AA6 circt. diag.and figure them out ...........SRSLY they basically haven't changed outside of the the tube sockets since 1936 BTW
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and thank you for your rely

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