Some cores don't display properly on Sony Trinitron

[MiSTer Consoles]

Hi all. I've got an issue where certain cores are "scrambled" when they are launched on my CRT. I've got it connected using Direct Video through a modified VGA to component adapter. I believe the issue might be due to some cores not being exactly 60Hz. I know these Trinitrons can be picky about the signal frequency. I tried setting vsync_adjust=0 to force 60Hz and then vga_scaler=1 to make sure VGA was connected to the scaler. That didn't seem to help. Any thoughts on how to set up my MiSTer so that all cores will display properly?

[FoxbatStargazer]

If you're using direct video none of those settings should do anything. They are for scaled (non-direct) output only.

You should be more specific about which cores you have in mind. Some default to sub-NTSC refresh, others work above 15khz like Ao486, others don't have any analog output like ao486. In these cases you want to apply a fix that is specific to those cores, so as not to mess up your working cores. This example is an adjustment specifically for ao486 to make DOS prompt decent on an SD television, you can change that to the proper core name to apply to another core. In the core settings you should change the aspect ratio to wide/full and disable any filters.

Code: Select all

[ao486]
direct_video=0
video_mode=720,240,60,cvt
vsync_adjust=0
vscale_mode=1

[MiSTer Consoles]

If you're using direct video none of those settings should do anything. They are for scaled (non-direct) output only.

You should be more specific about which cores you have in mind. Some default to sub-NTSC refresh, others work above 15khz like Ao486, others don't have any analog output like ao486. In these cases you want to apply a fix that is specific to those cores, so as not to mess up your working cores. This example is an adjustment specifically for ao486 to make DOS prompt decent on an SD television, you can change that to the proper core name to apply to another core. In the core settings you should change the aspect ratio to wide/full and disable any filters.

Code: Select all

[ao486]
direct_video=0
video_mode=720,240,60,cvt
vsync_adjust=0
vscale_mode=1

I know that the SNES core is one that is problematic. Would your settings work for that one? I’m not near my MiSTer right now, but there are several other console cores that don’t display properly. I predominantly use just console and arcade cores on my setup.

[FoxbatStargazer]

I'm super sus if an NTSC analog SD TV can't handle SNES. I'd be more likely to blame your converter.

But sure I think [SNES] should work for testing. I'd probably use video_mode=512,240,60,cvt for evener pixels.

Come to think of it, you might need something higher to raise the pixel clock for the converter to work. Maybe 2048,240,60,cvt.

[MiSTer Consoles]

I'm super sus if an NTSC analog SD TV can't handle SNES. I'd be more likely to blame your converter.

But sure I think [SNES] should work for testing. I'd probably use video_mode=512,240,60,cvt for evener pixels.

Come to think of it, you might need something higher to raise the pixel clock for the converter to work. Maybe 2048,240,60,cvt.

Unfortunately I tried both of those video modes and they did not give me a stable picture for the SNES core. It actually seemed much worse than the default. I ran through all the console cores and I have this issue with the old Sega Genesis core (not the newer Nuked-MD one), the Sega CD core, and the Wonderswan core. I believe the WS runs at 75Hz so that's to be expected. The Sega Genesis and CD cores should definitely be good at 60Hz though. I do have an analogue IO board I could use instead of the HDMI to VGA/component converter. It's just strange that only these few cores seem to have this issue. I'm using a modified Moread adapter which is supposed to be one of the better ones for Direct Video.

[FoxbatStargazer]

I would bet the problems are direct_video related. Each core produces its own super resolution, some may be more or less compatible with the converter.

[MiSTer Consoles]

I would bet the problems are direct_video related. Each core produces its own super resolution, some may be more or less compatible with the converter.

Gotcha. I’ll go back to the analog IO and see if those cores work normally on this TV set. Thanks!

[MiSTer Consoles]

So I swapped over the analog IO board and there were still issues with getting a stable image on the SNES, Genesis, and Sega CD cores. I even connected MiSTer to another Trinitron set I have and the issue was the same there. I did a Google search and found this EXTREMELY helpful post you created awhile back which goes through some setup steps for CRTs. I noticed this section in particular about settings that might cause issues with getting a stable display.

Core HUD Settings

Dunno what you want to call this section but there are a few crucial things to mention here. First is the ScandoublerFX, occasionally called Scanlines. Turning this option on is going to force 31khz output on most cores, which isn't going to sync with SD TVs, so its something you have to watch out for. It's also the primary tool for faking scanlines on 31khz+ displays for 15khz cores. This setting is saved per-core, so just disabling forced_scandoubler does not adjust this setting, something to watch for when switching between a VGA monitor and SD TV.

Second thing is that several cores have toggles between 60hz on and off. AO486 often runs refreshes like 70 or 75hz, the Wonderswan core is also at 75hz. The 60hz mode lets you push 60hz even over the default analog output, without having to invoke the scaler with vsync_adjust=0. Again crucial to get these cores to sync with many TVs.

Third is that in the new video processing menu, most things there only apply to the scaler, however color correction applies to the analog output as well. The default correction profiles provide a number of options to raise the gamma curve (and therefore raise contrast, at the risk of losing shadow detail)

I truly applaud this initiative and hope we can come together to make something useful!

I checked all three cores to see if any of the ScandoublerFX were enabled. The SNES core did have scanlines enabled, so I turned those off. I didn't see anything enabled for the other two cores though. I fired up the MiSTer after making the changes and the SNES core works now. That must have been the issue for that one. I noticed the discussion about a 60Hz toggle in the WS core. I enabled that and now it works on the Trinitron as well. I looked over the Genesis and Sega CD cores again and saw they both had the region set to EU which presumably was forcing 50Hz for PAL. I changed that to US and now they both have stable images too. Yay! I never realized how many of those settings could cause issues with CRTs. Hopefully if someone else has any problems like this they will see this post and discover how to fix them.

Do you happen to know where those per core settings are stored on the SD card? It would be nice to be able to fix them in a text editor vs. having to go into each core while it's running and make the updates.

[rhester72]

Do you happen to know where those per core settings are stored on the SD card? It would be nice to be able to fix them in a text editor vs. having to go into each core while it's running and make the updates.

They are in /media/fat/config, but are binary and subject to change with core updates.

[MiSTer Consoles]

Do you happen to know where those per core settings are stored on the SD card? It would be nice to be able to fix them in a text editor vs. having to go into each core while it's running and make the updates.

They are in /media/fat/config, but are binary and subject to change with core updates.

OIC. Good to know. Thanks!

[FoxbatStargazer]

Completely forgot about scandoublerfx. Literally hoisted by my own pertard, er, past post. Glad it ended up helping you!