[R-390] Resistors for the R-390A and beginner help

[Ed Zeranski]

......  In my experience with the above radios, the the resitors that have
tended to be
> > out of tolerance have been screen resistors, resistors in the plate
> circuit,
> > or cathode resistors, since they are usually carrying the most power.

        Yes! That has been my experience when reworking WWII mil sets. Thats
why I prowl the 'junk' boxes at swapmeets looking for 1 watt and above
carbon resistors. Screen reistors seem o be the hardest hit.

Also, beware of "black beauty" capacitors. ( or any wax/paper condenser)
> Check
> > some of the various restoration pages for a list of problem capacitors
> that
> > should be replaced immediately, such as ithe cap. that couples to the
> > mechanical filters in the IF module.

        Coupling and bypass caps are cheap especially compared to a non
replaceable inductor.

 And tighten all hardware, especially
> > screws that mound tube sockets to the chassis.  Repeated heating and
> cooling
> > cycles will cause them to loosen resulting in poor grounding over time.

        I drill out the rivets, clean the mating surface with a Dremel, use
Deoxit, then use a new rivet.

         Do
> > not spray bandswitches with contact cleaner or deoxit...

        Get some of the long wooden handled industrial 'Q' tips then shave
the end thin with a razor blade. You can spray the splint with Deoxit and
use it to wet the switch contact. The polishing film used for fiber optic
connectors works too.