So you had wobble in 480p before the mod? From what source? The only 480p source I recall using extensively on these monitors is a Dreamcast's RGBHV, which always looked 100% solid. I also used 480p RGBS from an N64Advanced board, which also looked perfect though it was using the custom D-Sub Retro-Access cables that solved wobbling in all scan rates for me (and that one in particular was also wired for c-sync and reaching the monitor with TTL, another factor worth exploring IMO).famiac wrote:after testing i can see that the mod (replacing the amp for h-sync with a clamp) eliminated the wobble at 480p but made it slightly worse in 240p.
And did you have a chance to also test 480i (or maybe you meant to say 480i rather than 480p)? Like I mentioned before, using an external RGBS (sync on composite) -> RGBHV sync separator made 240p 100% rock solid, but introduced slight but noticeable wobble for 480i, whereas the original RGBS input was perfect on 480i but had terrible wobble with 240p. Maybe this can be a hint for figuring out this puzzle.
Another hint may be to find out the sync cleaners that Retro-Access uses (or used to use) in their D-Sub cables. I don't know if they alone fixed the problem, or if the Extron matrix that I hooked them up to was needed for raising video level sync to TTL as well, but with that setup I had no wobble on any scan rate. It'll be another month or two until I have access to those cables again, but once I do I'll try to see if I can open the hood on one of them to check.