Hi Rick,
I also have the Zenith 900 X and I use a faroudja NRS for 800 X 600 on an 80 inch 16 X 9 Stewart Screen. I don't have that issue. However, is it visible to you when you look into the lenses? If so that elimiantes the screen. Some screen makes do add artifacts depending on gain. Also, if necessary I can get you to some folks that know this unit extremely well both as consultants and at Zenith. I really enjoy my unit now after making changes in the screen and scaler. Let me know.
I also have the Zenith 900 X and I use a faroudja NRS for 800 X 600 on an 80 inch 16 X 9 Stewart Screen. I don't have that issue. However, is it visible to you when you look into the lenses? If so that elimiantes the screen. Some screen makes do add artifacts depending on gain. Also, if necessary I can get you to some folks that know this unit extremely well both as consultants and at Zenith. I really enjoy my unit now after making changes in the screen and scaler. Let me know.