[R-390] R390-A Cal tone

[Ed Rafferty]

greetings fellow R390 caregivers,

I have a Motorola R390-A  which  has recently begun to  offer up its
resident  cal tone  when the BFO is switched to on  and the function switch
is set to Cal.  no matter what frequency is selected..  that is, the cal
tone remains constant and  does not zero beat  at the usual 100 kc
intervals.
could this be tarnished/ dirty contacts on the  function switch plates? or
elsewhere?   I haven't  discovered a thread that might relate to this issue
noted in the archives,
thanks in advance for any leads/ possibilities/ suggested courses of
action,
v/r
Ed R.  N4MDA