[R-390] Filters and Wandering gain

[quartz55]

I had the IF module out while watching a 3 hr movie.  Put it in cold, turned it on, and gain was low.  Touched the 4K filter out connection and snap, the gain came right up.  Let it warm up for a while and gain dropped off, touched the 4K filter again and snap, gain came back up.  Did this 3 times but final time the gain did not come back up fully to -7V diode load with the 4K.  The other filters were still at set gain.  Looks like for some reason the 4K filter is doing something, but maybe the switch is doing something bad too?  When I touch any of the other filter output connections in their respective BW position, nothing happens except a tiny pop.

Do I need to pull the connections off the top of each filter to check out the switch S503, everything in there is sort of interconneted  The switch always seems consistent when switching BW, it's just when I touch the 4K filter output.  And I mean just touch.  I tried a plastic tool and it did nothing.

I'll check out some resistance measurements between wafers/connections/rod.