[ARC5] Deaf BC-454

[David Stinson]

Brian, take a look at the trimmers atop the tuning capacitor.
Do you have any which are, once peaked, fully meshed or
unmeshed?  I ask because I have encountered oxidation
between the normally bonded plates and terminals on some
A.R.C. tuning caps in both the receivers and transmitters.
This is becoming a common problem, along with Hi-Z grounds.

If you look at the end of the stators where the connection is
made to the circuit, there is a "press fit" bar on the end of the
stator.  I've found the contact between the stator and this
connection bar can go "Hi-Z."  I've also found Hi-Z contact
between a set of plates in a receiver's tuning cap rotor.
I first encountered it in a BC-454 many years ago.
It would suddenly go "deaf" as you describe.
If I gripped the tuning dial and flexed it, the signals would
return to normal.   This was oxidation between some rotor
plates of the Mixer section of the tuning cap.  I used
a bit of soft copper wire and a large battery to "spot-weld"
all the plates back to the rotor shaft and that solved the 
problem.

If you find any of the trimmer caps fully meshed or unmeshed,
set the one according to the manual and the other at half-mesh.
Remove the internal covers and power the receiver.
Use an insultated shaft like a pen case to gently flex the 
rotors,
stators and the little connection bars at the end of the stators.
See if the signal levels change.  If they do, you can remove the
cap and use a hot iron to solder the connection bars to
the stators.  If it's the plates, you might try the "spot weld" 
fix.

Seen this several times at the connection end of the stators in
the transmitters.  PA won't resonate until the bar is soldered
to the stator.  Be careful not to overheat the little plastic 
balls
used to mount the stators.

GL OM DE Dave AB5S