Rainbow Edges When Using CRT

[Narenek]

Hi,

I've been using my mister with Antonio Villenas' VGA to s-video converter going to a JVC PVM with zero problems. All looks great and it works perfectly.

However now I've got my Sony kd-28dx40u back out from the corner it was hiding in to use with my consoles I decided to try the MiSTer on it. The TV works perfectly well with both my Megadrive and Sega Saturn. The Saturn is connecting using S-video so it would seem the S-Video on the TV isn't a problem, and the VGA to S-Video converter and cable work perfectly fine on the JVC. Yet when I connect the Mister to the TV I get the rainbow like banding as in the picture attached

mister.jpg (1.5 MiB) Viewed 3737 times

The banding does seem to lessen if I flip the switch from NTSC to PAL on the converter, but the Saturn is a Japanese model with a MODE in it so the majority of games I play are NTSC with zero problems.

As the hardware all seems fine I'm hoping there's a simple solution to resolving the problem that someone knows of. My ini file is as below, and works fine for the JVC PVM.

[MiSTer]
;VIDEO MODE
video_mode = 8
;VIDEO SETTINGS
menu_pal = 0
dvi_mode = 0
fb_terminal = 1
fb_size = 0
video_info = 0
hdmi_limited = 0
vsync_adjust = 2
;VGA SETTINGS
forced_scandoubler = 0
ypbpr = 0
composite_sync = 1
vga_scaler = 0
direct_video = 0
;VIDEO SCALING
vscale_mode = 1
vscale_border = 0
;AUDIO SETTINGS
hdmi_audio_96k = 0
volumectl = 1
;MISC SETTINGS
key_menu_as_rgui = 0
rbf_hide_datecode = 0
;bootscreen = 0
recents = 1
gamepad_defaults = 1
keyrah_mode = 0x18d80002
reset_combo = 0
osd_timeout = 30
bootcore_timeout = 10

[Nemesis2k]

Not sure if this will help or not but have you tried flipping the sync switch on the io board?

Also try putting ypbpr=1 in your ini

[Narenek]

I think I tried the ypbpr option, but have to admit I probably tried a couple of other things at the same time. I will test it tonight when I'm home from work.

I'm guessing you mean the sync on green switch on the side. I have not tried that but will again try tonight.

[aberu]

This same thing happened when I used composite video with Antonio's adapter. I gave it away after he said it would be fixed in the "next version" and that I could buy it again

And I doubt it would actually be fixed because the MiSTer is generating the original clock frequency of the original video signal, antonio's adapter is just passing this into a specific frequency that doesn't match. There's a few reasons possible why it looks the way it does.

1. His original older design used an external y-trap which is causing the rainbow effect on brighter colors. His new design changed the analog chip to one that has an internal y-trap, so this should mitigate the effect but not eliminate it.

2. The modification of the original video signal creates behavior that is different from the original system.

He advertises his adapter as producing the same video signal as original hardware, but this is technically impossible as he has two oscillators that you can switch between 50 and 60hz, but original hardware didn't all use the same exact frequency.

His other products are great, just kinda wished he wasn't selling something with this flaw and advertising it as "same as original hardware" which is highly misleading. You won't be able to get rid of this problem without modifying the core clock frequency.

[Narenek]

Ok so it sounds like the S-video is great for the PVM but not for the CRT.

I'm looking at the VGA to Scart adapter, it's just 10 euro and I've plenty of scart cables lying around. It looks like it sends stereo sound through the converter which is nice as sound is part of the reason I want to use this CRT, it kind of kicks ass for games. Do you have any knowledge if this product works better than the S-Video one?

[akeley]

A 10 Euro adapter is unlikely to work properly. If your TV takes RGB scart then you'll need either a proper MiSTer VGA-SCART cable or UMSA.

Also, if you don't have the I/O board you'll need a Direct Video dongle.

[Narenek]

This looks to be a proper one as below, though he does also have a VGA-Scart cable

https://www.antoniovillena.es/store/pro ... t-adapter/

Edit: Also I have the I/O board so am going from that VGA port

[akeley]

Ah, I thought you mean some generic Amazon thing. It says it works only on his boards though, so better make sure first.

[Narenek]

Well thanks for the help guys but turns out I just don't know how to use my CRT

On that model of TV when you choose the input option EG scart 1, scart 2 and input 3, you don't just choose the input but also the signal you are inputting EG On input 3 you choose between input 3 composite and input 3 s-video.

But as they are the same input it still shows a picture when I'm plugged into the s-video socket and chose the composite as the input. Because i'm inputting s-video but telling the TV it's composite it messes it up. I was choosing composite as it was the first option when i hit input 3, and as I saw a picture I thought ok it's working.

Maybe I just misremember my old CRT's and that's how they all worked, but up until my Saturns scart cable died and the I got the Mister going i'd never used S-video before. It also teaches me to RTFM

That said I've ordered a vga2scart from a UK seller so will see how that goes with the Mister

[MiSTer_Kirk]

If it's the following, that you have ordered, then that is what I am using, and it works great on the Mister.

https://www.ebay.co.uk/itm/114489119197