[Hallicrafters] Replace C63 to fix SR-150 "hum"

[Mike Peron]

Found the culprit.....thanks to the handful of fine people that responded to my earlier plea for assistance on this fine site. I too was suspect that only one "golden" 12BE6 product detector (V6) could possibly solve my 60 Hz "hum" problem. Very puzzling problem since my trusty old Hickok 752 repeatedly said "no leakage" on my other "humming" tubes. Didn't make any sense so I dropped a new 50 cent 5 uf in parallel with the potentially offending V6 cathode bypass cap "C63" and instant silence!!  That old half inch long black 45 year electrolytic must have seen its better days. Now all my12BE6s work like a charm with (no hum). Unfortunately, there is no manufacturer's logo on any of these tubes but my "silver plate" was the golden one. Also the additonal of a condom looking metal shield was a super idea that didn't work (very puzzling since grabbing the tube with my hand produced a ton more hum).

DO NOT BE FOOLED...as with life, the first hint is likely not the root cause of a problem. Besides, caps are much cheaper than "golden" tubes. I suspect that there are enough nuances between manufacturers that one tube made up for a dysfunctional cap (go figure). 

As one of you folks told me....ahhhh... the mental stimulation of playing with boat anchors (besides a lot cheaper than the real ones!!). 

Thanks for all for the great suggestions. 

73's

Mike WB6UTW