[R-390] Popping noise problem

[Barry Hauser]

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