[Hallicrafters] SX-28A Issues

[Richard Knoppow]

----- Original Message ----- 
From: "Joe Connor" <joeconnor53 at yahoo.com>
To: "Waldo Magnuson" <magnuson at mac.com>; 
<hallicrafters at mailman.qth.net>
Sent: Tuesday, April 01, 2014 7:04 PM
Subject: Re: [Hallicrafters] SX-28A Issues


How old are the filter caps? Could they be leaking? What you 
did with parallel caps would work if they were open but not 
if they were leaky or shorted.

Joe Connor
On Tuesday, April 1, 2014 9:59 PM, Waldo Magnuson 
<magnuson at mac.com> wrote:

Hi, My SX-28A was playing okay (after a long rest). Then the 
BCB station went away and the audio became a loud hum. I've 
tried: pulling the 1st audio amplifier (v12, 6SC7), hum 
remains, Substituted both 6V6GT audio output tubes - hum 
still present, paralleled C48 & C49 (power supply output 
caps) and C47 (cathode bypass for 6V6s) - no change, B+ 
measures maybe 150v (not schematic 250v). Any suggestions 
welcome.
>Skip W7WGM

     Joe has probably got it. Disconnect the filter caps and 
put others in their places. Even if only one is bad replace 
them both.  The symptoms are typical of bad filter caps.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com