[R-390] Hi to list

[Barry Hauser]

Hi John:

Welcome aboard!  We need some new action around here.

Well, y'see, the R-392 was made for rough service -- to ride on the back of
a jeep alongside it's companion transmitter.  It's also waterproof even in
use, with the proper caps and connectors in place.  One listmember tested
this in his bathtub a couple of years ago.  The good news -- they float.
The bad news -- face down.

Anyway, the thing is designed to be jostled around, so if you mounted on the
back of your jeep, you'd never notice the intermittent as the "tapping"
action would be automatic.

Seriously though, many of these are in very good shape because they either
didn't see much use and/or they're fairly well sealed and clean inside.
That in addition to the heavy dose of MFP coating has kept them well
preserved.  It seems as though your intermittent is either a failed solder
connection or a loose screw -- or one where there has been some light
corrosion or chemical reaction due to dissimilar metals, etc.  The solder
connection can be good to start -- not a cold solder joint -- however trace
amounts remaining impurities or rosin inside the joint can cause it to go
intermittent, open up, or even turn into an accidental component -- 
resistor, capacitor -- or even a semiconductor (diode, not LSI chip) as one
listmember reported.  Refreshing the joint is the fix.

Also, many have traced such problems to basic hardware -- screws 'n nuts -- 
particularly those that have grounding tabs and tube socket mounting points
which are often used as grounds.  I don't know if that module has captive
nuts (pressed into the aluminum) or separate ones.  What you might try doing
is gently backing off the screws that mount the V204 socket - so that you
don't lose friction if there's a separate nut & starwasher under them, then
tighten firmly.  Might also be another screw nearby.  Worth a shot.

If that doesn't do the trick, the next most likely thing is a solder joint.
Also try unplugging and replugging any connectors.  I assume you cleaned the
other tube sockets as a tap in one spot can affect something a few inches
away and be somewhat deceptive.

Hope this helps.

Barry


----- Original Message ----- 
From: "John Seboldt" <k0jd-l@seboldt.net>
To: <r-390@mailman.qth.net>
Sent: Saturday, March 20, 2004 9:22 AM
Subject: [R-390] Hi to list


>
> Greetings to all, just saw the list on the qsl.net list of lists and
> thought I'd say hi. Have been playing with an R-392 for about 2 years now,
> in fair condition, and working pretty well with only a little workout of
> the switches. Got all the manuals in .pdf from various online sources, so
> someday may open it up further. Only annoying quirk is that it cuts out
> completely on occasion, and can be brought back to life by tapping on or
> near V204. I know it's not the tube since I've swapped it, and a squirt of
> Caig DeOxIt in the socket doesn't help either. Haven't yet had the courage
> to figure out how to get into that top deck area, and have only done a
> cursory reading of the manuals to figure out how - looks kind of involved.
> Someday... meanwhile some discreet tapping is enough.
>
> John Seboldt K0JD
> Milwaukee, WI
>
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