[R-390] SW R-390a Second Pass

[Roger Ruszkowski]

Jim,

I agree,
Are you looking at it?
Or trying to listen to it?

We only need one for the Smithsonian.
Lets get on with fixing the rest of them.
New caps, resistors and things under the deck are plain out of sight.

Roger



-----Original Message-----
From: N4BE_Jim <N4BE_Jim at Yahoo.com>
To: r-390 <r-390 at mailman.qth.net>
Sent: Sat, Feb 15, 2014 6:57 am
Subject: [R-390] SW R-390a Second Pass


I put my first 390a, a SW oldie, through its first refurb about 8 years ago.  I 
thought it was a hot Rx then.  After sitting more or less idle since then, it 
became once more deaf, compared to my 2nd radio, a Collins mfg 390a. So I 
launched into it again.  Discoveries:  I thought I had done a fairly 
comprehensive recap and resistor replacement in the SW back then.  But after 
further investigation with a capacitance meter, I now suspect just about every 
mica box and ceramic disc cap are out of tolerance or otherwise leaky. I was 
having to screw in too much inductance on the mixer and RF slugs.   So I am 
replacing all caps across IF and RF tuned circuits.  Already about 50% done, the 
performance is much better.  I will also be going inside the cans that have caps 
in them.  Likewise on the carbon comp resistors, drifted up out of tolerance.  
Replaced every bloody resistor with new carbon films.  Almost like a new radio 
fresh off the assembly line now.  Lesson learned: I am over 
 the idea of wanting an unmodified museum piece.  Shotgun approach works.

Jim N4BE

Sent from my iPad
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