[Drake] TR-7 Receiver Noise Question

Sun, 28 Mar 2004 20:06:55 -0500

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
> >
> >_______________________________________________
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> >[email protected]
> >http://mailman.qth.net/mailman/listinfo/drake
> >
> >
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