[MRCA] R-392 BGO

[DSP3]

Folks,

I've been working on an R-392 receiver, the arguably the 5th or 6th one 
that I've had over the years, with real problems in the IF.  That is, 
the thing worked "fine" on 8 kHz but dead on the 4kHz and 2 kHz 
positions.  Checking components for the past several months, nothing 
really untoward was discovered.  Without the book this time, some of 
what I was doing was chasing the tail.  Today, for some reason I 
fathomed a possible problem.  Sure enough.......  Looking at the IF 
cans, we see the variable "top" end, with inserted fixed coils that 
narrow things down.  I elected to try and re-align the receiver at the 2 
kHz position as see what might change.  Injecting the (at the time) 
required large 100mv signal, I got some throughput.  Doing an alignment 
brought everything back to life and working OK down to about 1uv.  After 
the fact, it /should/ have been a BGO, or Blinding Glimpse of the 
Obvious, but it had not been.  Fixes are always accomplished at the last 
place you look, this time no exception.


Jeep -KI3HVG

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20161124/658e07a8/attachment.html>