Just to close the door on this one... despite my proclamation that the springs were pushing the roller assy's down as far as they would go, they were not. I couldn't see that they weren't, but after rearranging all wires (and there's 4 grouped together that are "involved" with one of the rollers) I found the flicker had gone away. Stiff wires got me again!
Thanks for the responses!
George