Read your thread twice just to see if I missed any thing, I agree with most every thing that has been said, but having a vary similar problem a coupla of years back, and when all was said and done it turned out to be the reciver (long story) sent it to radio south with a request for bad parts to be sent back and what it. got the reciver back with a note and a part called a front end cristal.

Just a thought Bob