[R-390] Intermittent Filter

[Mike Hardie]

The 4 Kc filter in my '390A is "intermittent".  It works OK when the radio
is first switched on.  After warming up even slightly, if the mode switch is
moved to standby then to AGC, or if a different filter is selected then 4 Kc
reselected, the audio is extremely weak. (Almost not there.)  If no
selections are changed after the radio is first turned on, the 4 Kc filter
works normally.


The other filters work normally so far as I can tell.

Does anyone have an idea before I start the honest-to-goodness trouble
shooting?

Mike VE7MMH