HDMI 4K Monitor Unable to Get a Stable Sync

[sacredbanana]

Hi all

I have a 4k monitor connected to the HDMI interface on my MiSTer (along with a Commodore 1084S 15khz monitor attached to the VGA on the IO board). A few months ago (must have been some update that caused the issue) my HDMI monitor has struggled to keep an image on the screen for more than a couple of seconds before going black for a few more seconds then repeating. This ONLY happens in the main MiSTer menu or in terminal windows such as when running the update script. I've turned off VRR and things like that but I can't seem to get a stable image. Sometimes I even have to power the monitor off and then on again to even get an image at all. When running cores, everything is perfect. Any idea how I can fix this?

[FoxbatStargazer]

check for a [main] section in your mister.ini, that governs settings specifically for the menu core. Maybe you have some different video settings there? Another thing to watch out for is pal_menu, it should be 0.

[sacredbanana]

Thanks yeah I already checked for a main section in the ini file and there isn't one. PAL mode is disabled but even if I enable it, the issue remains. It's really annoying, especially if I'm using the terminal or running the update script since that only outputs to the HDMI.

[sacredbanana]

Hmm was just in the Minimig core and when it switched screen mode in AmigaOS to an interlaced mode it started to become unstable again (it's usually fine when I switch screen modes). Looks like its not just the MiSTer menu that has the issue.

[EDIT}: I was able to stabilise it just now by changing the output to 1280x720. Not ideal, I'd expect this 4k 144hz monitor to be able to support a 1080p signal from the MiSTer...

[charmless]

Have you tried a 1440p signal? My 1440p monitor also behaves weirdly with 1080p when for example running the update all script.

[FoxbatStargazer]

I'm also noticing some weirdness in menu core on my LG C1 when using video mode 8. Its not going black but there is horizontal wiggle. This does not apply with mode 0 (720p), mode 12 (1440p), or supplying a custom video line, even a 1080p one. Seems to be the same with VRR on or off. I don't think it always behaved this way so there may have been some change.

[charmless]

I'm also noticing some weirdness in menu core on my LG C1 when using video mode 8. Its not going black but there is horizontal wiggle. This does not apply with mode 0 (720p), mode 12 (1440p), or supplying a custom video line, even a 1080p one. Seems to be the same with VRR on or off. I don't think it always behaved this way so there may have been some change.

Can't speak for the LG TV:s but my 1440p Asus Monitor has done the horizontal wiggle (which is a phrase that needs to be used more often) in 1080p using video mode 8 for at least a year. But you are totally right that it only happens in that mode.

[sacredbanana]

Unfortunately 1440p mode 12 gets no sync at all for me . I might have to stick with 720p

[charmless]

Unfortunately 1440p mode 12 gets no sync at all for me . I might have to stick with 720p

Even if you change the aspect ratio on your TV? Have you tried mode 14?

[FoxbatStargazer]

Menu core doesn't support mode 14. Many cores don't and default back to 1080p.

[charmless]

Menu core doesn't support mode 14. Many cores don't and default back to 1080p.

Ah, that's too bad.