Well, back home now and did some checking.
Replaced hdmi cable with an unused new one. No change.
Resolution set to 1080i (but checked others). Still flashing.
Now for the strange one.
I have flashing video on about half of the channels in the ION mux at 3840mhz on the AMC1 bird. The others in the mux are fine. When checking the signal, I get strong Signal and Quality on all channels. But on the Signal screen there are 10 vertical bars as well as the horizontal Signal and Quality bars. Only 2 of the 10 vertical bars are shown for the flashing channels.wheras all 10 of the bars are lit up for the non-flashing video channels. ????????? Differences on the same frequency? When I check elsewhere on other birds, I see the same thing on the Signal screen, Flashing-only 2 bars, Steady-all 10 bars.
BTW, when I say "flashing", I don't mean pixellated or a weak picture. It is a good, strong video but only for a split second, then black, repeating.
Is the STB a goner? Bad tuner?
If so, suggestions for a replacement?
Joe