[1000mp] Receive all but shot

[N3SL at aol.com]

Naturally, right before a contest (RTTY RU), I have a (seemingly) major problem.  Before ripping open the 1000MP, I throw this out for insight/suggestions/comments:

Two nights ago all was well.  Last evening (and still tonight) receive seems to be all but dead.  To hear even U.S. sigs on 80 or 40, the volume control needs to be at 1-2 o'clock.  Even then, with the strongest signals, there is no S-meter indication on receive.  Transmit seems to be normal: full power, drives the amp fine, etc.

I've had that nasty "sticky relay" problem in the past, so wondering if the relay has finally died.  The other thing that comes to mind is the relatively recent (like Sept) installation of the Inrad roofing filter.  Could that have gone bad?

All other settings appear normal.  I've disconnected and reconnected "everything" without any changes.  As I say, it worked fine Tues.  No one touched it until I turned it on Wed and found the above.

I'm suspicious of the relay.  If that indeed seems the likely culprit, is there any quick fix or test? or am I out of luck for contesting and looking at a service situation?

Thanks for assistance,
Steve