"Reverse" modulation hum

Bob Jackson bob at NOFROWNS.NET
Mon Nov 29 18:50:31 EST 2010


My bad - I had too many windows open. I'd read Jim's first and didn't notice I used your email to reply to. My apologies.

Bob
  ----- Original Message ----- 
  From: J. Forster 
  To: Bob Jackson 
  Sent: Monday, November 29, 2010 5:44 PM
  Subject: Re: [BOATANCHORS-TEMPE] "Reverse" modulation hum


  Err...  thanks to who?

  -John
  ==============


  > Aha!  Bad AGC cap! AGC goes nuts w/o a signal. Thanks to Jim Simmons -
  > should've occurred to me - my bad. Thanks to all that replied.
  >
  > Bob  AG5X
  >
  > PS - This is a "Globe'ciever" - modest 4-tube gen. cvg. rig  from days of
  > yore.
  >   ----- Original Message -----
  >   From: J. Forster
  >   To: Bob Jackson
  >   Cc: boatanchors at lists.tempe.gov
  >   Sent: Monday, November 29, 2010 5:25 PM
  >   Subject: Re: [BOATANCHORS-TEMPE] "Reverse" modulation hum
  >
  >
  >   Heater-cathode leakage or bad bypass cap in the IF?
  >
  >   The AGC cranks up the gain w/o a signal.
  >
  >   FWIW,
  >
  >   -John
  >
  >   ===============
  >
  >
  >   > Strong humming noise heard only between stations, not while tuned to a
  >   > station. Doesn't sound the same as pwr supply "bad caps" hum and is
  >   > stronger. Ideas ???
  >   >
  >   >
  >   > Bob  AG5X
  >   >
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