We have a M-4300-PM since 2008, starting about 6 or 7 weeks ago, amidst the frequent thunderstorms, the TV picture became more and more pixalated as weeks went by but only on a few channels, upper channels were worse some became unwatchable (but many were in Spanish so we didn't care). Then the problem drifted into ABC (5.1), CBS (2.1) with annoying bands of pixalization, still watchable but NBC (7.1) was fine, only occasional, minor random pixalization. Yesterday CBS and ABC became totally unwatchable, NBC had somewhat more pixalization than previous, becoming quite annoying, most upper channels above 26.1 were out of service or unwatchable. I knew this type of pixalization to be a weak signal problem in general.
Then I looked behind the TV and A/V and realized the cable from the wall first went into the M4300-PM then to the TV, so bypassed the M4300-PM and Wallah!! all channels perfect!! including all the ChiChi channels!!!(maybe I should become fluent in Spanish)
So the M4300-PM was the culprit. A new one costs $260-300, so I was wondering if anyone had a schematic, maybe I could just open it up and replace the MOVs or whatever is on the F connector protection circuit.