[Milsurplus] Navy RBC - Any Experts?

[David Stinson]

Anyone here have some tips on reviving a Navy RBC receiver?
Band One works fine.  The other bands are deaf but will receive

if I bypass the ANT box, so it's a good bet the last fellow golden-

screwdrivered the bandswitch alignment in that box.

Will the bandswitchs in the boxes rotate 360 degrees?

 

https://photos.app.goo.gl/VW2ywaYToTkPwGpG3

 

But the biggest problem right now is Band Two.

The local oscillator simply will not track.  The closest

I can get is with the coil all the way out and the varicap

all the way to one end of travel, and that leaves the high

end off almost a meg.

 

Since Band One is working well, I assume the LO circuit itself

must be OK and the problem is in the tuned circuits.  I removed

the LO box and replaced all the padder caps across the coils

with NOS 2% Silver Micas.  This was no help.   Band One is

right where it was and so is Band Two.   There is one of those

tiny brown cylindrical ceramic caps- this one 20 pFd- padding

the variable cap.  In 40 years, I have never seen one of these

little caps fail, but given that the rest of the LO works fine on

Band One, and there isn't much more in there but

that circuit and the tuned elements, I'm suspecting.

Anyone seen this or similar?

 

Pulling these boxes is a big pain not because they are

more complicated than those in something like a BC-348;

it's horsing that Big Bertha around on the bench.  Woof!

 

73 Dave AB5S



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