[R-390] Should this work?

[Barry]

Hmmm.  I just realized something.  Without the meters in place, C101 isn't
grounded (limiter circuit).  Perhaps that's why the thing isn't working?
I'll have to ground that tonight and see if it makes a difference.

Barry - N4BUQ


> Yeah, you should of heard something. Even with no input to the IF deck I
> think you can still hear the noise spectrum change when the IF bandwidth
is
> changed around.
>
> Since that IF module tested OK it sounds like a wiring problem. The audio
> path is somewhat twisted - out to the Diode Load (is the jumper there?) -
> back into and out of the Noise limiter circuit and front panel control -
and
> then to the audio deck.
>
> John
>
>
>
> > Working on the "new" R390A.  I have it mostly back together (at least
> > enough
> > to run some tests).  I tested everything except the RF deck by
> > substituting
> > the modules into my working radio and everything I tested checked out
> > functional.
> >
> > When I powered up the radio, I got nothing on the audio except a small
hum
> > when the volume is turned up to 100%.  I didn't figure on hearing
anything
> > in the way or radio signals since the RF deck is in complete need of an
> > alignment, but I did expect to hear some noise.
> >
> > I injected the audio signal generator into pin 7 of the plug that
connects
> > the IF deck (P112) and was able to get good audio on both line and
local.
> >
> > I then decided to take the IF output from the working radio's RF deck
> > (with
> > the radio tuned to a good strong station) and plug it into the input of
> > the
> > IF deck on the radio under test.  Since I had checked the IF deck by
> > substituting it into the working radio and it does work there, I figured
I
> > should get some signals that way.  Still nothing.
> >
> > Is this a valid thing to try?  I realize the IF deck still needs a
touchup
> > for alignment, but it should be close enough to hear something through
the
> > chain.  It worked when I substituted it into the working radio a few
weeks
> > ago so I assume it should still be working.  Unless something has broken
> > since then (and I'll try substituting it again to make sure), I would
> > think
> > this should produce some signals.  No?
> >
> > Thanks,
> >
> > Barry - N4BUQ
> >
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