Connecting 15khz CRT RGB TV via VGA

“640x480” 13.150 640 684 748 836 480 486 489 525 interlace -hsync -vsync

PAL 50: “768x576” 14.750 768 790 859 944 576 581 586 625 interlace -hsync -vsync


Thanks a lot! It works. It’s great, displaying low quality content, like this ancient rip of the 80s anime ‘Hokuto no Ken’.(3rd post) You really can’t see the compression artifacts.

I also swapped the installation drive into the HP EliteDesk using Intel HD4000 graphics and that too works! (Also incredible how portable Slackware is) Though I have a feeling that the picture quality is worse than with the ATI card.
Can that be - that i.e intel graphics deteriorate in quality at low pixel clocks??
Of course it is propable that this is just a case of placebo effect, it is just hard to objectively compare.

Also will there be resolutions that the Intel graphics can’t display? Could you please provide the console (320p?) modeline. I’m afraid this is where the Intel graphics will fold. I just want to make sure every rom I throw on there works and finally get this retro gaming setup working.

Found both of these TVs in the dumpster: A ‘Thomson 21mg130’ - Made in Poland and the aforementioned ’ FUNAI 20A 1110’ - Made in Italy - at least there is an italian label at the back.

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You can work out the basics of modelines easily out yourself. For example, the 480i modeline I provided

“640x480” 13.150 640 684 748 836 480 486 489 525 interlace -hsync -vsync

Turns into:

“640x240” 13.150 640 684 748 836 240 243 245 262 -hsync -vsync


“320x240” 6.575 320 344 376 416 240 243 245 262 -hsync -vsync

(horizontal values are recommended to be dividable through 8, at least with older drivers, may still work otherwise or automatically adjusted.)

I recommend Windows Custom Resolution utility /WinModelines Windows tools and run through Wine if you want to better understand modeline generation and how to adjust. Or maybe there are good enough online calculators, I don’t use Xrandr (CVT) for modeline generation generally.


Ok. I have used this online calculator: and it worked fine so far (for CRT monitors). I just don’t know the common TV resolutions and when it’s supposed to be interlaced etc.

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Ah ok, the problem with the GTF standard seems to be that it does result in too low frequencies for TVs, if I enter 640x240@60 Hz it gives me 249 total lines which results in significantly lower hsync (14,94 kHz) than the standard 15,6-7 kHz. It depends on the TV model, it’s possible for some to go under 15 kHz and over, but not by much. You’ll generally want to stick around the middle.

Best thing in your case is probably to try Switchres out. It’s getting too much into basic stuff here otherwise. Use Retroarch’s Rgui for CRTs, it can also be setup for manual use of superwide resolutions like 2560x240, which can be sufficient for NTSC stuff.

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Isn’t that only intended for Windows? As far as I’m concerned it’s doing the same thing as the xorg modelines under Linux…

I meant CRTSwitchres in RA.