Those are all good ideas!

If you have checked the transponder signal levels and half of them are bad (the evens or the odds, I can't remember which), that could mean that the power supply is only sending 13 volts up the line and can't do the 18 needed for the other half.

I have heard, but not checked, that DirecTV have been feeling pretty swell with themselves lately and have quit making pretty much any deals, but it is worth a phone call! If you get someone to come out and do an upgrade, they will have to fix or replace the faulty stuff, and their install rates have been ridiculously low as long as you keep them out of the "custom" range of tasks.