Fw: [R-390] R-390A trouble (BIG CORRECTION)

[Jim Temple]

Ooops.......

I meant IF deck,  not RF deck.  Sorry for the mixup.

So I substituted a working IF deck for my IF deck and the symptoms are
exactly the same.

Yikes, sorry.

Jim

----- Original Message -----
From: "Jim Temple" <jetemp@insightbb.com>
To: <r-390@mailman.qth.net>
Sent: Thursday, March 28, 2002 3:46 PM
Subject: Fw: [R-390] R-390A trouble


> Hi Roger and list,
>
> OK, I have a friend who inherited a R-390A from his father.  I picked up
his
> RF deck, and upon installation in my receiver, the symptoms are exactly
the
> same as with the original symptoms below.  Now what??
>
> Jim
>
> ----- Original Message -----
> From: "Jim Temple" <jetemp@insightbb.com>
> To: <r-390@mailman.qth.net>
> Sent: Thursday, March 28, 2002 3:15 PM
> Subject: Re: [R-390] R-390A trouble
>
>
> > Hi Roger and list,
> >
> > OK, here is what I found.  (Narrowing down the sypmtoms).
> >
> > 1.  In AGC position.
> >     a.  RF gain at 5.  AGC voltage essentially 0.  Little rushing sound.
> > Receiver apparently stable.
> >     b.  As RF gain is increased, background/rushing noise slowly
increases
> > to a level that seems normal and strong.  Noise sounds normal and
stable.
> > TO A POINT.
> >     c.  As RF gain increases toward 9, the AGC voltage abruptly
increases
> > and the audio breaks into the putt, putt/screeching sound.  The AGC
> voltage
> > will continue to increase to about 7-8 volts, and the putt,
> putt/screeching
> > continues as long as there is AGC voltage.
> >     d.  The carrier level remains essentially 0, until the putt, putt
> > begins, then the carrier lever meter shows a smooth increase to 100.
> >
> > 2.  In MGC position.
> >     a.  Symptoms are the same until the point that the background noise
> > becomes strong (about 9 on the RF gain), then the receiver abruptly
blocks
> > as if from a strong signal.  The carrier level meter will JUMP to 100.
> >
> > 3.  An observation is that the problem occurrs at the same position of
the
> > RF gain control, whether the function switch is AGC or MGC.  The only
> > difference is that the receiver putt, putts in AGC and blocks in MGC.
> Both
> > increase the carrier level to 100 (slowly in AGC, abruptly in MGC.
> >
> > I hope my observations are clear, if not please ask to clarify.  Thanks,
> > guys.
> >
> > Jim
> > 73, KF4ICZ
> >
> > ----- Original Message -----
> > From: "Roger L Ruszkowski" <rlruszkowski@raytheon.com>
> > To: <r-390@mailman.qth.net>
> > Sent: Thursday, March 28, 2002 1:09 PM
> > Subject: Re: [R-390] R-390A trouble
> >
> >
> > >>
> > >> Hi Roger and list,
> > >>
> > >> OK, I want to fix this receiver. Here goes. Jim 73, KF4ICZ
> > >
> > > Jim, your on it now. Roger.
> > >
> > > The question please.
> > >
> > >
> > > Does this putt, putt occur when in the MGC function?
> > >
> > > If no, then its most likely an IF deck AGC voltage generation problem
> and
> > > not the RF deck at all. If yes, then it is not and AGC problem at all
> and
> > > we are looking for a bad CAP.
> > >
> > > Roger.
> > >
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > R-390 mailing list
> > > R-390@mailman.qth.net
> > > http://mailman.qth.net/mailman/listinfo/r-390
> > >
> >
>