Success! Ok i figured it out. This is going to be a long one so sit back, but anyone with a similar problem, i hope this will work for you. Again I am running RetroPie on a raspberry Pi 3 with a Pi2Jamma adaptor and i ran the retropiergb mod to output to a 15khz monitor. so i figured that this was an issue with the run command, so i found a file in the /opt.retropie/configs/all, named runcommand-onend.sh . In it there is a line for HDMI timings that was different then the one in the global config.txt in the boot folder. so i added the correct timings and # out the originals and it worked! but then for some reason mame was outputting a very stretched image at 1920x240, so i went into the configuration options in the run command menu and changed the settings in the edit custom retroarch config option. In it you will see that the custom viewport is set to 1920x240, so i just added a pond symbol before the commands. Since the layout seems to be UK it is a £ instead of # for us Americans but it works just the same. and now mame defaults to the listed game resolution. I have no Idea why these options did this but I wasn't going to let this beat me. I hope this helps.

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@MasterOfTheWind

I think what you are trying to do is very complicated and you have to have quite some knowledge to get this working.
So many people can't help you with that.

Have you looked into an easier solution ?
You can use the "CVBS/Composite Video" output of the Raspberry pi if your TV supports it.
The the quality of the CVBS/Composite video signal is quite acceptable on an old TV.

@buzz I've tried this before, but I've tried again just now, to make sure.

overscan_top=40 overscan_bottom=40 overscan_left=40 overscan_right=40 overscan_scale=0

While this does add the overscan on the console, it also adds it to EmulationStation and RetroArch while emulating.

@ReadyPlayaWon cool i need to try that

@chipsnblip This is more than anyone could ask for. On behalf of the retro community and myself.

Thank you!

@Nikorasu081 glad you got it working now!

Regarding the 117Hz display, I'm not sure. That number is actually computed from pixel_frequency timings so maybe is dependent on the current GPU clock. Are you using a good power supply?
Regarding the flickering, I have zero experience on using the composite out and CRT, so can't help you much there. Sorry! But yes, it does seem like having 117Hz instead of steady 120Hz can be the issue as you gradually get out of sync for the black frame insertion.

@240pnoob said in 240p Over Composite to CRT Problems:

any easy guides on how to do this? Keep in mind I have only had a raspi for about 24 hours, with 20 of them being me fighting it.

You really should read on about the Raspberry Pi and RetroPie in general before trying to customize your installation. Themes can be installed from the RetroPie setup script - https://retropie.org.uk/docs/Themes/.

@youxia that's giving a more accurate and sharp image but frequently changing back to HDMI isn't very convenient even by using a tvservice startup script. Also setting things up for different arcade games is a pain. Quite ideal for setups permanently hooked on a CRT though.

@athman8 280p is supported via HDMI but you'll need to find an adapter that will give out the same resolution and also a CRT monitor that accepts 240 lines. The easy way to get 240p out of the Pi is via composite on a CRT TV by setting sdtv_mode to either 16 or 18 (NTSC or PAL).

@capeman Yeah, cool project! Some day I'd like to do a CRT build.

@lilbud check out online reviews of the TS100. Might be just the ticket for a slightly smaller budget iron. It is the one I have my eye on ATM.

@Nossral

I would go with RetroTINK Ultimate and a VGA to Scart cable with two external Audio connections.

To get better audio instead of using the built-in 3.5mm audio jack a would recommend a usb soundcard.

@vykyan

No problem. Glad it helped.

for NES my CRT likes
-240p screen format
-640x480 render resolution for the screen format
-717x552 (5 x -40 offset) retroarch scaling resolution
-bilinear filtering set to off

For SNES I use a 702x496 retroarch custom scaling resolution with a 12 x -8 offset and bilinear filtering on. Genesis looks pretty good with bilinear filtering on and standard 4:3 resolution

@youxia said in Using "super resolutions" with a crt - any way to correct the emulationstation aspect ratio?:

Super resolutions are used for GPIO and HDMI outputs, composite needs different configs.

Ya I know, I got my composite setup perfect, but the only way to get rid of the rainbow moire on dithered textures was to use a shader made specifically for outputting over the pi’s comp plug, doesn’t add much blur, but it’s def not perfect. Was hoping somebody figured out how to hack this res into the yellow plug, haha. Wishful thinking.

This post worked for me for the onstart onend runcommands https://retropie.org.uk/forum/topic/11628/240p-and-mame-scaling/12

Ok I've tried a couple different things and I've run out of ideas. I know it's probably some stupid little thing I'm missing, but I have no clue why RetroPie is ignoring config.txt even with overscan_scale=1. Is it a glitch?

Ok I think I finally fixed it to the point where it doesn't make me angry. I decided to try someone else's config.txt as mine was cursed or something :P I went here: https://www.dropbox.com/sh/6hdpa7893c3ked1/AABCXqUHjXI-C3PUdcq4f8jya?dl=0 and downloaded the "custom_res" config. I renamed it to "config.txt", changed the resolution to 320x240, and added some custom overscan numbers. The lines are still there, but they don't affect the text and only appear on a black screen. I'm sure I could go further and 100% fix it but right now I'm happy. Whew!

@Pietze I'm not able to see the game art on the game lists (I've downloaded the NES pack and placed it on ~/.emulationstation/downloaded_images/nes/, is that enough?)

@capeman Thank you.
I'll just stick with the vga crt set up, I'm more than happy with the results right out of the box (I'll have a play with some settings myself) compared to the lcd with scanline shader effects.

Much appreciated.