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

[N4BE_Jim]

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