embarrassing, but this is why i sign my posts “bonehead”…
as i was re-checking my cables between my Decklink, 1800 and monitor, i found that i had the OUTPUT Y cable (rather than the INPUT!) connected as the sync ref. how surprising that when i switched these, and looped my 1800 to itself, my rolling problem was gone. : ) all this and no black burst generator!
thanks for your patience and good ideas on this.
thanks for helping out a bonehead,
jtn