[R-390] Silver solder

[Norman Ryan]

Hello, Scott,

Loosening mechanical grounds, dabbing on a bit of DeoxIT, and
retightening is sufficient IMO.  Look out for varnish under fasteners. 
There won't be further elecrolytic action unless the radio is operated
in a location like St. Julian's Creek.  Ordinarily the tubes' warmth
will keep dampness in check.

Silver solder is useful for the RF deck, but be aware of its high
melting temperature.  It's sufficient simply to desolder signal path
connections with a solder sucker and resolder lightly with good quality
63% tin rosin core solder.  Clean off rosin right down to Teflon
insulators with Q tips dipped in suitable solvent.  DeoxIT the plug-in
coil contacts and the tripod-like clip under the adjustable capacitors.

Do the above once every half century!  :-)

73 de Norman KG4SWM


scott wrote:
> 
> Is silver solder recomennded for any of the joints?
> 
> I have just re-capped the AF module.  There are so many mechanical grounds
> in this set!!  What makes it worse is the fact that the chassis is aluminum.
> Aluminum oxidizes and makes for poor connections.  Aluminum wiring in a
> building is an electricians dream--lots of service work.  A special compound
> is now required for aluminum connections.  Why should this radio be
> different??  Boy it just looks like a lot of intermittent and hard to trace
> problems in the making.  I am loosening all pertinent
> connections....applying Deoxit....then re-tightening.  Would seem foolish
> not to while each module is on the workbench getting rebuilt.