Blonder Tongue Question

[kf4rca]

I would say that IS a modulator. Some modulators I have seen use an F connector for video input (wierd). A processor goes from channel in to channel out. For CATV systems it is important to convert local channels to another channel to avoid co-channeling problems.
BUT, in pict 4 it says OFM750HB. The HB tells me its a High Band unit (Channels 7-13).
Its very likely you have a component failure in the unit.
From what I remember from my CATV days, the mixer diodes fail due to lightning strikes nearby.