From my (very basic) understanding some games have odd timings and the Framemeister is affected as well.
I had this problem on:
Warlords (sync goes in and out on the “demo” screen as the colors change and upon starting a new game)
Star Wars Empire Strikes Back (Destroying an At-At)
Star Wars Return of the Jedi (Going through the force field to get to the death star)
I do not have these issues on my crt through SCART. I’ve also tried both my Harmony Cart and the original cartridges.
What I have done so far is poked through the OSSC sync settings and tried:
Analog sync LPF turned off
Hsync tolerance set to max 39.2
Vsync threshold set to max 30.7
This seems to help but it does not completely fix the issue for example in Empire Strikes Back when I destroy an At-At it only drops out sometimes and in Warlords it doesn’t drop out on the demo screen but it does starting a game, Return of the Jedi has no change it still drops.
I have plenty of games that are completely unaffected like Pitfall, River Raid, Ms. Pac-man.
There seems to be some sort of fix on the Framemeister called “Sync-Time” that may alleviate it but I do not own one to try.
Does anyone know of any other settings that may fix this or is there something that can be done in firmware to make the OSSC “tolerant” to some of these games on the Atari 2600?
Is this issue similar to Chrono-Cross on PSX where it drops going to the menu? My understanding is that that is a resolution change.