Ok, I switched the cable to the other port on the LNBF and I now have transponder 2 on sats 119 and 110. Still missing 119 tp 6, 10 and 16 and 110 tp 12 & 10. (This was after unplugging the RG-6 from the receiver and running a check switch to reset and plugging it back in).
I did pull apart every connection and it appears that the little blue plastic thingie inside the F81 is cracked on both ends (is that considered a dielectric?), so I'll go get a new barrel connector for that.
Any equipment you recommend to check voltage or continuity on the line? I mean, clearly I have some continuity if I'm getting most channels. I've been meaning for some time to get a voltage tester for other things.