Degraded image and sound through SCART Hub

Discussion about displays and related hardware including MiSTer filters and video settings.
Fed
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Degraded image and sound through SCART Hub

Unread post by Fed »

Hi All !

I am using a MiSTer device and VGA to SCART cable both coming from Ricardo's UltimateMister store.
Running the VGA to SCART cable directly from the MiSTer into my Commodore 1081 monitor I obtain a fantastic picture.

Now when adding an Otaku-Games SCART hub into the middle the audio and video signal are greatly degraded on the monitor. The sound is all choppy and the image has some interference sweeping the screen as well as colors slightly off.

Any clues on what could be causing the problem ?
Note that a PS1 and Saturn using RGC UK SCART cables running through the same SCART hub are displaying pristine sound and image... I am starting to wonder if it is simply that the signal sent by the MiSTer device is not made to be routed through a device such as a SCART hub and will only produce good results when plugged directly to a tv/monitor.
Hopefully somebody in this forum does have experience on this matter and will be able to help me progress with my troubleshooting.

Have fun all of you !
GamingDoyle
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Re: Degraded image and sound through SCART Hub

Unread post by GamingDoyle »

Were you able to figure this out? I have the same problem. Consoles and supergun through the scart switch look and sound great but MiSTer output for both audio/video is messed up.
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jlancaster86
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Re: Degraded image and sound through SCART Hub

Unread post by jlancaster86 »

I've run my MiSTer through an Otaku-Games switch without any issues (via Direct Video, not an analogue I/O board).

I'm just guessing here, but maybe the signal coming from your MiSTer is off-spec in some way and that's running afoul of the switch's internal circuitry.

Could it be as simple as the CSYNC signal being TTL and not 75 Ω? Is that even possible with an analogue I/O board?
Fed
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Re: Degraded image and sound through SCART Hub

Unread post by Fed »

I ended up getting a different switch. A Taxon Tools and never looked back.
GamingDoyle
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Re: Degraded image and sound through SCART Hub

Unread post by GamingDoyle »

Ah bummer, I thought it would be the ultimatemister cable not the switch given the consoles work perfectly, but the other scart switch works well with the same cable?
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Re: Degraded image and sound through SCART Hub

Unread post by GamingDoyle »

Thanks jlancaster, I’ll try my other MiSTer before giving up on having this one switch do everything. Too bad though
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Re: Degraded image and sound through SCART Hub

Unread post by GamingDoyle »

jlancaster86 wrote: Sat Sep 11, 2021 11:38 pm I've run my MiSTer through an Otaku-Games switch without any issues (via Direct Video, not an analogue I/O board).

I'm just guessing here, but maybe the signal coming from your MiSTer is off-spec in some way and that's running afoul of the switch's internal circuitry.

Could it be as simple as the CSYNC signal being TTL and not 75 Ω? Is that even possible with an analogue I/O board?
I heard back from otaku-games. They say it won’t work with the analog board vga out because “they don’t provide the power necessary to run the switch”. So maybe it works for direct video but not through the analog IO board. Bummer.
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jlancaster86
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Re: Degraded image and sound through SCART Hub

Unread post by jlancaster86 »

GamingDoyle wrote: Tue Sep 14, 2021 3:25 pm
jlancaster86 wrote: Sat Sep 11, 2021 11:38 pm I've run my MiSTer through an Otaku-Games switch without any issues (via Direct Video, not an analogue I/O board).

I'm just guessing here, but maybe the signal coming from your MiSTer is off-spec in some way and that's running afoul of the switch's internal circuitry.

Could it be as simple as the CSYNC signal being TTL and not 75 Ω? Is that even possible with an analogue I/O board?
I heard back from otaku-games. They say it won’t work with the analog board vga out because “they don’t provide the power necessary to run the switch”. So maybe it works for direct video but not through the analog IO board. Bummer.
Just curious: Does it start working if you leave a second console turned on? I believe the switch can draw power from any of the connected devices, even when they're not selected.
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Re: Degraded image and sound through SCART Hub

Unread post by GamingDoyle »

I have the auto-switching one so multiple would interfere with each other. Good thought though
Frogybloop
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Re: Degraded image and sound through SCART Hub

Unread post by Frogybloop »

I actually just ran into this problem as well. I made my own cable based on viewtopic.php?p=13102#p13102 and was getting really cruddy signal on my PVM through the otaku auto switcher, but the cable worked fine when connected directly. After a bit of digging, I realized that all other scart cables in my collection that worked with the Otaku had voltage running through pin 8 on the scart head. I just added a wire between pin 16 and 8 on the scart head (chaining the RGB switch voltage from the analog board) and this seems to have fixed the problem. I believe I also read that pin 9 on the analog board VGA port provides voltage thats switchable between 5v and 3.3v via a jumper on the board. So you could also probably wire this through to pin 8 on the scart head to achieve the same results. Hope this helps anyone else that runs into this issue!
GamingDoyle
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Re: Degraded image and sound through SCART Hub

Unread post by GamingDoyle »

Nice, thanks! I will give this a try, sounds like an easy fix. I was planning to round back to this and investigate but now I don’t have to ;)
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Re: Degraded image and sound through SCART Hub

Unread post by GamingDoyle »

For anyone stumbling upon this thread, Frogybloop’s suggestion works flawlessly.
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