[Hallicrafters] Hallicrafters Digest, Vol 86, Issue 8

[James Liles]

Hi Richy:

Is the hum in the transmitted audio or audible from speaker in transmit 
mode?  Is the receive audio clean especially at the low end?  Kindest 
regards Jim K9AXN

-----------ORIGINAL MESSAGE ------------------
Message: 1
Date: Mon, 14 Mar 2011 18:52:01 -0400
From: ss409ss at aol.com
Subject: [Hallicrafters] Hum on tx audio
To: hallicrafters at mailman.qth.net
Message-ID: <8CDB0B190D2E4B7-700-3885 at webmail-m045.sysops.aol.com>
Content-Type: text/plain; charset="us-ascii"




   I've had this on and off hum on TX with the Hurricane, sometimes it does 
it, sometimes it doesn't. I decided to rebuild the supply and replaced all 
of the caps but not the 30-30uf chassis mounted one. I made two printed 
circuit boards from G10 epoxy, mounted all of the new caps in the HV supply 
and covered the tiny caps with the old covers. Anyway the supply is stiff, 
all recapped with new, I still have a hum/buzz on tx, especially when I drop 
the mic gain to zero it becomes more prevalent. The radio has new tubes, PS 
all recapped except the 30-30. I tried different mics, plus it does it 
without the mic and in tune mode as well as ssb.. Anyone have any ideas on 
where to look? Tnx Richy N2ZD