[R-390] Complete Re-Cap and Change all resistors ?

[chuck.rippel at cox.net]

Wow, you must have one that has seen a LOT of use.  I've never seen one 
in which ALL the resistors had drifted out of tolerance.  If they change 
10%, I change the resistors.  I worry more about DC leakage through the 
caps than a change in value.  That said, there are a number I change 
either because they have failed multiple times over the radios I've done 
or, I want to take advantage of a different media type to either clean 
up the audio a bit or to increase audio reciovery.

Be REAL CAREFUL to replicate lead dress in the RF deck !

--
Chuck Rippel

"Never miss the chance to shut up."
- Robert Gates

>
> 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
> ***********