[Drake] TR-7 Receiver Noise Question

Sun, 28 Mar 2004 21:19:23 -0500

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----- Original Message -----
From: "Jim DiMauro" <[email protected]>
To: "Larry Taft" <[email protected]>
Cc: "Drakemail" <[email protected]>
Sent: Sunday, March 28, 2004 8:06 PM
Subject: RE: [Drake] TR-7 Receiver Noise Question


> For the benefit of the list, suggestions included a check of the 10 volt
> adjustment pot (see below), removing and re-seating the plug-in boards,
mic
> connector and power connector (includes cleaning plugs with DeOxit); and
> possible noise coming from the LM380 audio output chip.
>
> Tnx agn,
>
> Jim
>
> -----Original Message-----
> From: Larry Taft [mailto:[email protected]]
> Sent: Sunday, March 28, 2004 3:35 PM
> To: [email protected]
> Subject: RE: [Drake] TR-7 Receiver Noise Question
>
>
> Hey Jim,
>
> Post the list.
>
> Larry K2LT
>
> At 01:54 PM 3/28/2004 -0500, you wrote:
>
> >Thanx to all who took the time to respond to my inquiry.  I received as
> many
> >different ideas as there are people who responded, so there appears to be
> no
> >single, common cause for my problem.  No biggie, I'll find it when I have
> >the time to dig into it.  While I'm in there I'll clean and reseat the
> board
> >contacts, as that reportedly cures many ills.  Regarding the 10 volt pot,
> >I'm not going to touch it unless I'm prepared to do the alignment: even
if
> I
> >don't turn it, a noisy or dirty pot can change adjustment with any sort
of
> >disturbance and I don't want to touch it until I have the time to go all
> the
> >way, if necessary.
> >
> >73,
> >Jim
> >
> >-----Original Message-----
> >From: Larry Taft [mailto:[email protected]]
> >Sent: Sunday, March 28, 2004 8:44 AM
> >To: [email protected]
> >Cc: [email protected]
> >Subject: Re: [Drake] TR-7 Receiver Noise Question
> >
> >
> >Jim,
> >A possible source of the noise is the 10 volt adjustment pot on the power
> >supply board.  Pull the top cover of the TR-7 and lightly tap on the
> >right-most pot on the PS board located on the right side just behind the
> >front panel.  Do NOT give it a twist as that will then introduce you to
the
> >alignment process for the rig.
> >73,  Larry  K2LT
> >drakerepair.com
> >800-687-9161
> >
> >At 07:26 AM 3/28/2004 -0500, you wrote:
> >
> > >Hi All:
> > >
> > >My TR-7 exhibits a low level background noise that sounds similar to
> random
> > >atmospheric static.  The noise comes from inside the radio.  It's
audible
> > >when a dummy load is connected, the RF gain is turned down and there's
no
> > >external noise to mask it.  It's most noticeable (to the point of being
> > >extremely annoying) when using the 500 Hz CW filter; it's also present
> when
> > >using the other filters, but it's almost inaudible and isn't a problem
> with
> > >other modes.  It's independent of the audio gain control, so that's a
> clue
> > >as to where to start looking for the noise source.  Before I dig in,
has
> > >anyone heard of this before?
> > >
> > >Thanx & 73,
> > >Jim
> > >WA2MER
> > >
> > >_______________________________________________
> > >Drake mailing list
> > >[email protected]
> > >http://mailman.qth.net/mailman/listinfo/drake
> > >
> > >
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