GFXV9990 and OSSC - best settings?

By JohnFante

Resident (49)

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22-05-2018, 21:03

I have just gotten a GFXV9990 (Tecnobytes) for my Turbo-R and connected it to my OSSC via the VGA connector on the OSSC.

The pictures is ok but there is a bit of noise - waves across the screen - and the included Bomberman clone (Battlebomb) is not centered on the screen. I was therefore wondering if anybody else have the same setup and have experience adjusting the OSSC for this?

So far I have not touched the OSSC settings since they have just worked. And if it aint broken - do not fix it :-)

Thank you in advance!

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By roadfighter

Champion (363)

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22-05-2018, 21:53

Hi, We had the GFX lite on the OSSC to and had the same problem.
But if you have a FRANKY or a playsonic cable from Supersonic, use that one.
Its a vga to scart cable and then the picture is much better.

By JohnFante

Resident (49)

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23-05-2018, 06:35

Ok. Thank you :-)

Can I use all VGA to scart cables or does it have to be a playsonic cable? Can not seem to find that cable anywhere ...

By Grauw

Enlighted (7317)

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23-05-2018, 08:39

Even though the Powergraph uses a VGA connector, it does not output VGA (31 kHz), it outputs plain RGB (15 kHz). So if you connect it to the OSSC VGA input probably the default settings aren't right.

You may be able to tweak them, but iirc the OSSC's VGA port also lacks a filter that the SCART input has so that may also make a difference. Iow, you may get there with settings, trying to make the settings for the VGA input the same as those for the SCART input, but a VGA to SCART cable may also work. I think the wiring of such a cable is also described on the Tecnobytes site, so you could make one yourself too...

By JohnFante

Resident (49)

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23-05-2018, 10:07

Just checked the FAQ at Tecnobytes:

"Can I use a VGA to Scart adapter?
Yes, you can! Just choose a good one... There are some low quality adapters in the market..."

http://www.tecnobytes.com.br/p/v9990-powergraph-light-faq.html

I will give that a go!

By Grauw

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23-05-2018, 11:12

Don’t use an active VGA to SCART adapter though... Since the V9990 doesn’t actually provide a VGA signal I doubt that those will work. Just use a passive adapter cable.

The Powergraph uses a VGA connector because a SCART connector is way too big for the casing, and also because in Brazil they don’t use SCART and they often do use 15 kHz-compatible LCD monitors (or so I heard), which are apparently easier to find there than they are here. But for all intents and purposes it’s delivering SCART RGB signals, so you should really consider it as such.

By JohnFante

Resident (49)

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24-05-2018, 20:20

I got a cable but apparently it was a scart to vga and not the other way around. That means that it is configured for scart output and not input and that apparently is not the same ...

Therefore I have to rearrange the pins in the scart. No big problem. The instructions are her:

https://github.com/mist-devel/mist-board/wiki/ScartCable

If someelse gets the same problem :-)

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