Pipercub

OK, I did the composite mod to my 2600 and it works great, two RCA females on the back and it is all tied into my 6 way switcher with the other classic video game systems. I have all that fed into the input on my PC and life is good. I have noticed on a few games a strange distortion where a small section of the screen may be out of alignment. Clearly RF issues are not present. I did read in a few mod descriptions and how to-s that someone discovered that if you lift two pins on the TIA those problems go away. It further mentioned that Atari had these problems when they were using composite to demo the units trying to avoid RF problems. NATURALLY, the two pins are never named. Anyone know what two pins are being refered to? And more importantly, why?