[Hallicrafters] SR-400A Cyclone III HUM REMOVED

[Carl]

Hum is often due to corrosion at riveted tube sockets and ground lugs. A 
slight movement may be all it takes to cure, at least for now.

Carl
KM1H


----- Original Message ----- 
From: "Tom McDaris" <ab8bw1 at chartermi.net>
To: <Hallicrafters at mailman.qth.net>
Sent: Tuesday, December 15, 2009 4:58 AM
Subject: [Hallicrafters] SR-400A Cyclone III HUM REMOVED


>I have had an extremely nice SR-400A Cyclone III for some time but have had 
>a problem with receiver hum.  I have been talking it up amongst other 
>enthusiasts with varying results and advice.  The hum was never bad enought 
>to get real serious about so it took me a while to finally do something 
>about it.  I had replaced the filter caps in the supply so what I ended up 
>doing is removing the radio from the cabinet and inspecting the audio 
>output section.  I re-heated some suspicious looking solder joints and 
>really saw nothing that looked out of the ordinary.  When I put it back in 
>the cabinet, that obnoxious hum was gone!  It just goes to show that 
>sometimes it is the simple fix that works!  73 AB8BW Carleton, MI.
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