PaulUK & everyone,
Yes indeed. Isn't it amazing what a poor ground connection and a little wild speculation can bring about? ;-)
Got everything put back together and with a properly grounded coax connected everything looks just as it should, electrically. I wonder how much current is leaking out that way? I wonder how it is affecting the modulator & amplifiers? What are they trying to filter?- what is the function of those caps?
Now only to find where all my RF is going! That is something which must be attacked one step at a time. Problem is nothing is mapped or labeled, and most of the runs cannot be easily traced. For some reason there was a dual run of coax in distribution; presumably VHF & UHF are split apart then mixed back together with a combiner right at the TV set. Or it may have been cable vs in-house? Should have been adequate isolation in the video room for that to not be necessary. Seems over-done to me. All I know for sure is the teachers here want to share videos amongst classrooms and there are not enough portable TV/VCRs to go around. I should remain well entertained for the next day or two trying to sort all this out.
Many thanks to all who responded!
