SIGMA RAIJIN RGB CABLE PROBLEM

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vasilas432
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SIGMA RAIJIN RGB CABLE PROBLEM

Post by vasilas432 »

I received today a RGB cable for my new Sigma Raijin control box and have a super bright image, looks white. I have to turn brightness and contrast to minimum-zero on my Sony BVM to make image to look as normal.
What I have to do to fix it?
Maybe pull down resistors in the scart? If yes how many Ohm?
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vasilas432
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Re: SIGMA RAIJIN RGB CABLE PROBLEM

Post by vasilas432 »

Put pull-down resistors 75 ohms on RGB lines in the scart but didn't change anything.
I figured out that only contrast is very high. Brightness is in normal levels.
My second BVM which is 1416p model can make contrast look ok by reducing it to 64%. But preferred it to be in the same range as other consoles because I suppose an ordinary CRT tv can't reduce enough the contrast as needed.
When I made bypass mod on my NEO GEO AES and put the picture encoder out of play, there was super high contrast output and color saturation. This was dropped to normal using 75 pull-down resistors and picture quality is awesome.

Any help will be appreciated.
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vasilas432
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Re: SIGMA RAIJIN RGB CABLE PROBLEM

Post by vasilas432 »

Sigma Raijin thunderbolt III model can't adjust brightness via S-BR regulator on the back of the control box for RGB. This is only for S-Video output.
It outputs pure RGB signal as it delivers it from the PCBS through jamma.
CPS2 and PGM output very high contrast so only a profesional monitor can handle it and reduce it to normal. Sony BVM 1416p can do that easily but a commercial TV can't.
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vasilas432
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Re: SIGMA RAIJIN RGB CABLE PROBLEM

Post by vasilas432 »

SOLUTION:
Found the solution and post it here so many people having a lot of brightness with this supergun, that outputs pure RGB signal, will be able to fix the issue easily and without the need to put RGB pots.
Except brightness that was put in normal levels there was a great improvement in picture quality in some pcbs.
Irem M92 was not crisp but now it is as crisp as it gets.
Crystal of Kings had a lot of color bleed in the characters health meter and here and there. Problem resolved 100%

PULL DOWN RESISTORS in the RGB lines in the scart is the solution. I put about 82 ohms. You can make experiments from 75 ohms to 120 ohms and choose your personal favourite brightness that depends on your favourite arcade platform.
When I put pull down resostors in the past and it didn't work, there was something wrong with the resistors but I didn't have a multimeter to check it out.
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