Sorry to hear you are having trouble with UHF, but how is CH 12 now?
You are certainly justified in suspecting the preamp, but don't ignore the possibility that something before it, or even after it, in the UHF chain isn't working like it should.
In a worst case troubleshooting scenario you will need to substitute each part of the UHF chain with a known good part, all the way to a TV, until the system is functioning like it should.
You can also think of it in a signal tracing manner. Is there a good UHF signal coming out of the antenna, is it coming out of the coax from the antenna, is it coming out of the UVSJ, is it coming out of the FM filter, is it coming out of another known good preamp, is it coming out of the power inserter, and so on.
You might end up with a completely independent reception system, but you will know what went bad. It might be a lot of work, but it is better than the frustration of the shotgun approach.
Last edited by rabbit73; 2-Sep-2015 at 10:51 PM.
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