My Sylvania TV's comb filter lives on

[wa2ise]

This was the comb filter board that was in the Sylvania set I had to part out a couple weeks ago. Now it takes composite NTSC video and makes S-video output. Modified it by adding a chroma buffer circuit to drive a 75 ohm load on an S-video jack. And to mop up residual chroma and hanging dots, added a 3.58 notch filter to the luma output. I think the Sylvania set had a notch filter in its chroma demod and color matrix board. Saw no hanging dots on this set. This new added notch here in this box is fairly narrow, so it doesn't trash luma resolution too much (just like back in the early 80s, this was a tradeoff of avoiding annoying artifacts vs desired picture sharpness). The main benefit this newly built box does is to much reduce cross luma into the chroma. This gets rid of the false rainbow crawling patterns you would see on the ref's shirt during football games.

The set it used to live in: