[Hallicrafters] SX-28A issues

[Mike Everette]

I think that all the Halli receivers with high power push pull audio, like the SX-11, SX-16, SX-17, SX-23, SX-25, SX-28, SX-32, S-27, S-36, SX-42 used the same B plus arrangement to feed the output tubes -- straight from the rectifier output, not going through the choke.

73

Mike
WA4DLF

--------------------------------------------
On Tue, 4/15/14, Richard Knoppow <1oldlens1 at ix.netcom.com> wrote:

 Subject: Re: [Hallicrafters] SX-28A issues
 To: "Mike Everette" <radiocompass at yahoo.com>
 Cc: hallicrafters at mailman.qth.net, magnuson at mac.com
 Date: Tuesday, April 15, 2014, 11:39 AM
 
 
 ----- Original Message ----- From: "Mike Everette" <radiocompass at yahoo.com>
 To: "Richard Knoppow" <1oldlens1 at ix.netcom.com>
 Cc: <hallicrafters at mailman.qth.net>;
 <magnuson at mac.com>
 Sent: Tuesday, April 15, 2014 7:22 AM
 Subject: Re: [Hallicrafters] SX-28A issues
 
 
 If I remember right (don't have my manual handy), the B plus
 for the push pull audio stage in the SX-28 comes from the
 rectifier tube side of the choke; so the only filtering for
 the audio B plus is the filter's input capacitor.
 
 The choke itself is only rated for 110 milliamps.  The
 audio section pulls close to an additional 100
 milliamps.  If everything went through the choke, that
 would be one huge hunk of iron (as if it ain't already
 big).
 
 Symptoms sound like the input filter cap may be open.
 
 73
 
 Mike
 WA4DLF
 
      I looked at the schematic, you are
 right about the output amp.
 
 
 --
 Richard Knoppow
 Los Angeles
 WB6KBL
 dickburk at ix.netcom.com