[R-390] Popping noise problem

[Jim Temple]

Adding to Barry's list, be sure to carefully check the ground that is
anchored by T207 under the RF deck.  When I cleaned and tightned mine, the
rig "sprang" to life.  This is one that is not anchored by a tube socket
screw and has several caps and resistors attached.

Jim

----- Original Message -----
From: "Barry Hauser" <barry@hausernet.com>
To: "Claudio Spiritelli" <oldradio@tin.it>; "R-390" <r-390@mailman.qth.net>
Sent: Monday, January 28, 2002 7:27 AM
Subject: Re: [R-390] Popping noise problem


> Claudio wrote:
> > I think a need to look more carefully at the suggestion of Mr. Joe
Foley,
> > even if I already tried that procedure..........
> > the noise source is localized on the "limiter" area...........does
anyone
> > had a problem were the socket of a tube was causing such a problem?
>
>
> Well, that reminds me ... of someone on the list who's always reminding us
> to check the nuts 'n bolts on the chassis and modules -- particularly the
> ones on the tube sockets. Apparently the lightest corrosion between these
> screws and the modules can cause breaks, high resistance connections or
> intermittents in grounds. This might be related to the problem
disappearing
> after the rig warms up fully.  The fix involves going over all the tube
> socket mounting screws with a screwdriver -- loosening and tightening.
>
> To that I'd add checking under the hoods of the multiconductor connectors,
> particularly the large rectangular ones on the audio and IF decks..  The
> cables stiffen up with age, the strain reliefs are not fully effective,
and
> when you go to unplug them, leads and shield braids can snap or crack.  As
> I've mentioned probably a half dozen times already -- I had a non-A where
> the main tie point ground inside the large AF deck plug cover was
broken --
> just a buss wire wrapped around all 12/13 braids goint to a single
terminal
> (13, I think ;-)  The cable going to that plug tends to droop down below
the
> chassis and get jostled when you move it around.
>
> Look for stuff like that.  You might have to dumb down to find this bug.
>
> Barry
>
>
>
>
>
>
>
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