i agree with buffalo chips. The mods should be run out within 3db of maximum output then padded at the output with external pads.If it looks good right out of the mod test point, the problem is most likely coming from another mod. Watch the bad picture while unplugging the other mods 1 at a time to determine which one is causing the problem. Replace the bad one.
This is CABL.com posting #322505. Tiny Link: cabl.co/mbv3R