Bill.Satellite, I've done what you suggest but the signal level on the SensarPro for the two real RF channels shows as two hyphens (no signal) no matter the gain setting. And, of course, no signal at the TV.
Bottom line is that when I reinstall my original power supply there is signal at the TV for both channels and both give good picture (CBS only in the evening. It breaks up during the day but there is signal though).
I suspect Jeff is right, either the SensarPro adds just enough noise to drown out the two channels or the amp is swamped. I don't know the signs of a swamped amp. I would have thought that would affect the UHF channels too? All the UHF channels come in just fine but they all have stronger signals than the two VHF channels to start with.