Genesis model 1 too dark with RGB cable

[grips03]

I bought a SCART cable and changed to Japanese RGB pinout to use with my XRGB2 and Sony LCD TV. Golden Axe intro is dark and greenish and not bright and blue. I've tried adding 220uf caps to RGB lines. I've tried with and without 75ohm resistors, and I get same results. Most games look ok, but would like to fix this issue. Any ideas?

[albino_vulpix]

Does the composite/RF give the correct colours? Are other colours OK (eg is the Golden Axe title bright red?) Do other RGB inputs work fine in the XRGB2? Are there any dodgy connections in the cable? (could attenuate the colour signals and make things dark.)

[grips03]

Colors good with audio/video cable. Other RGB devices that use the XRB2 work good. Connections all look great. I'm going to the Sega brand RGB cable and try that, otherwise it might be inside the Genesis. From reading it does not appear Genesis gen 1 need a video amp, right?

[albino_vulpix]

From reading it does not appear Genesis gen 1 need a video amp, right?

Correct, just a 75ohm resistor and 220uF capacitor in series with each colour signal.

How are you sending sync to the XRGB? If you're using the Genesis' CSync from the connector, you need a capacitor in series. 100uF will do.

[duo_r]

I built my cable using the optusnet diagrams:




Use this as reference for the cap/resistors, and also see the gamesx.com pinout:



See the gamesx.com pinout for sync pin. One of these pinouts is for the AV port, and the other the AV cable (make sure you figure out which is which).

http://members.optusnet.com.au/eviltim/gamescart/gamescart.htm

before I properly wired up the RGB lines, I had the problem exactly as you described. Also keep in mind Scart takes sync from composite, maybe you aren't sending the propper sync line to your XRGB?

[duo_r]

and as albino pointed out, it might need a cap on the sync line, since the Scart cable does not do that (or even pass csync).

[acem77]

never use composite video as sync on the xrgb,
use composite sync or luminance from the svideo output.
the genny should only need some resistors. remove the caps

[grips03]

I ordered a new cable. Does someone know where to get small 220uf and 100uf caps that could fit in the scart plug?

[duo_r]

surface mount might be the way to go on that one. U actually have some room to work with on scart plugs.

I ordered a new cable. Does someone know where to get small 220uf and 100uf caps that could fit in the scart plug?

[acem77]

the scart plug has enough room for the caps. surface mount is not needed.
are you still using an xrgb2? try it with out the caps.
most systems do not need them. snes is one that does.
some systems need an rgb amp, duo,nes,n64.
cdi,neo-geo,mvs,genesis,sms need resistors.
I have every system modded and conected to my xrgb2+
rgb systems->nes,snes,n64,sms,genesis,saturn, dreamcast,neo-geo,duo,cdi,3do,jag,supergrafx,psx,cdx,
all of these sytems worked fine on some rgb scart to component converters also

[grips03]

Got new scart cable today, rewired for xrgb2 - aka Japanese RGB and got same results. Again they came with resistors on the rgb lines.

Anyone have a working RGB cable for Genesis mod 1 that you use with xrgb2 that I can borrow? Promise to return and won't open up unless you say it's ok, just trying to see if this will ever work. I've tried 3 consoles (Genesis 1 and  2 SMS). Same results for all of them.

I'll of course pay shipping both ways.

Thanks,
Dave

[grips03]

My cable that does not work looks like.

audio mono = rgb21 pin 1 and 5
comp video = rgb21 pin 9
red = rgb21 pin 15
green = rgb21 pin 19
blue = rgb21 pin 20
ground = rgb21 pin 21 (case)

rgb = all have 75 ohm resistors

This cable connects to rgb21 connector on xrgb2. Should I change to 'sync' vs. 'comp video'?

Thanks,
Dave

[grips03]

Changed

comp video = rgb21 pin 9
to
sync = rgb21 pin 9

now I see even less, I see red Shinobi (SMS game) goes across screen then it goes all black.

Why won't this work? I'm going to trace the pinouts of my Sega Saturn RGB cable that works.

[grips03]

Double checked Sega Saturn RGB cable (original Sega brand cable).

Saturn uses:
right audio = rgb21 pin 1
left audio = rgb21 pin 5
comp video = rgb21 pin 9
5vdc = rgb21 pin 11+16
red = rgb21 pin 15
green = rgb21 pin 19
blue = rgb21 pin 20
ground = rgb21 pin 21 (case)

Going to remake Genesis cable this way to see if it works. There are no resistors on the Saturn cable.

[grips03]

Made Sega Genesis RGB cable with same pinouts as original Sega Saturn RGB cable (above), and get same results as before. There has to be a definitive thing to do when title screen looks good, then goes about 40% darker, game play is bright enough (little dark but not too bad). Test game is Shinobi for SMS and Golden Axe for Genesis.

Any ideas? Some of the previous posts seem to have conflicting information.

Thanks,
Dave

[albino_vulpix]

Any photos of your setup?

[grips03]

What photos would you like me to take?

TV, console, cable, XRBG2?

Thanks,
Dave

[albino_vulpix]

Inside of the RGB cable (scart end) would be most helpful.

[grips03]

Here is the version without the 75ohm resistors on the RGB lines. Both with and without resistors provide same result. I've also tried 220uf (35v) on RGB lines again same results.

Genesis Japanese RGB cable
audio = rgb21 pin 1 & 5 (gray)
comp video = rgb21 pin 9 - yellow
5vdc = rgb21 pin 11+16 black (gray jumper)
red = rgb21 pin 15 (red)
green = rgb21 pin 19 (green)
blue = rgb21 pin 20 (blue)
ground = rgb21 pin 21 (case) (shield with heat shrink tubing)

[albino_vulpix]

I'm not sure if an XRGB can accept composite video as its sync source. Use the composite sync in place of composite video (pin 1 on a Genny 1's AV output. If your cable doesn't have a wire connected to pin 1, run one straight from the console to your scart plug.
Let us know how this goes.

[grips03]

albino,
I tried that in reply 12 above, i.e. used sync vs. comp video, however screen is very dark with this method.

When I compared against my Sega Saturn RGB cable Saturn uses 'comp video' as well. This is the original Sega Saturn RGB cable from Sega and works great. In fact my PS1, Saturn, SNES, N64, Dreamcast all work good with this setup. Just can't seem to get Genesis or SMS to work properly

[albino_vulpix]

Did you use a capacitor in series with the sync signal? Take a picture of the screen so we can have a  better idea of what's going on.

If this doesn't work, it could be in the console itself. Do you have any other RGB capable devices? A YPbPr device would help too if you don't.

[grips03]

Here is Genesis game Golden Axe.

pic 1 is with AV cable.
Pic 2 is using 'sync' pin with 220uf cap, + side to console, - side to xrgb2. I get same results with 'comp sync' cable.

[grips03]

Here is SMS game Shinobi. I'm using Genesis with Power Base Converter. But I get similar results on true SMS.

Pic 1 is with same RGB cable with 'sync' and 220uf cap.
Pic 2 is into couple seconds later, notice how it went darker.
Pic 3 is with AV cable.

[Drakon]

wtf.  I built a rgb to s-video circuit for my genesis using a scart cable and board I found on ebay.  But mine works fine with just resistors on the rgb lines.  And it's brighter looking than my super famicom

[duo_r]

This is the exact problem I had with Genesis using my RGB Atlona box. For me this happened until I got the caps / resistors correct. I do not know alot about XRGB, so I cannot be of much help there, but this is the exact problem until the caps / resistors were placed.

In your test pictures, you do not mention using caps AND resistors, did you not try that?

Did you wire it like this (dont pay attention to the Scart plug pinout because that is different than yours):


UK Scart pinout in picture

Does XRGB2 use composite video (instead of sync) llike the Atlona Box?

Here is SMS game Shinobi. I'm using Genesis with Power Base Converter. But I get similar results on true SMS.

Pic 1 is with same RGB cable with 'sync' and 220uf cap.
Pic 2 is into couple seconds later, notice how it went darker.
Pic 3 is with AV cable.

[duo_r]

Dude your cap setup is the issue here. Obviously Composite Video is where the XRGB2 worked fine to pull sync. I found my Saturn did not need ANYTHING, and that all the diagrams I tested in this link here:

http://members.optusnet.com.au/eviltim/gamescart/gamescart.htm

worked perfectly. Notice how the Saturn doesn't need any caps, and I found this to be true. Genesis 1 needs Caps and resistors.

albino,
I tried that in reply 12 above, i.e. used sync vs. comp video, however screen is very dark with this method.

When I compared against my Sega Saturn RGB cable Saturn uses 'comp video' as well. This is the original Sega Saturn RGB cable from Sega and works great. In fact my PS1, Saturn, SNES, N64, Dreamcast all work good with this setup. Just can't seem to get Genesis or SMS to work properly

[grips03]

I did build it with resistors and caps on all RGB lines - had same issue.

I did not have 180 ohm resistor to +5 v line, pin 16 and 11.

So now going to make exactly like the circuit above and try that.

[grips03]

I built the RGB cable again with new parts using 75 ohm and 220uf and the like.

Same issue

So then I tried on Samsung 22 inch LCD monitor and it works perfect.

Now I'm trying trying to find out why the Sony BRAVIA KDL-52W3000 52 inch LCD TV is doing this.

Any ideas?

[grips03]

Called Sony, tech support they where no help. Tried another cable with exact pinouts XRBG2 needs (from the manual), i.e.:

1 audio L
2 audio R
9 c-sync
15 R
19 G
20 B

3,7,13,17,18,21 GND
2,4,6,8,10,11,12,14,16 None Connect

Same issue

For some reason the combo of XRBG2, Genesis/SMS, and this Sony Bravia = issue. If replace with Sega Saturn all is good, if I replace Sony with Samsung all is good.

[duo_r]

simply put your Sony TV doesn't like the sync signals transcoded from the XRGB2. What model do you have? I can tell you that I use the Atlona RGB to Component video and it works just fine on my Sony Bravia LCD HD TV that I bought late 2007.

Maybe you need to clean the sync signal using an LM1881 circuit?

[grips03]

I have Sony BRAVIA KDL-52W3000. I think sync has something to do with it. If I move to sync (what XRGB2 wants) from composite video then screen goes black. If I add a 220 uf cap to the sync line it works like it did when using composite video rather than sync. Perhaps a bigger cap will make it so the screen doesn't go dark during the title screen?

[acem77]

never use composite video as sync on the xrgb,
use composite sync or luminance from the svideo output.
the genny should only need some resistors. remove the caps

Did you try this?

[grips03]

Yes, in fact this is how I have it now. I did need a cap on the sync line otherwise screen was blank. Still has same issue on that darn Sony TV

[duo_r]

did u try another system with RGB to rule out the fact that ur TV just doesn't like the XRGB2?

[grips03]

Yeah Duo_r I have my Sega Saturn hooked up using same XRGB2 and it works great.

[albino_vulpix]

Have you ruled out the Genny's RGB output? If you don't have another RGB device, you could use a YPbPr input device to test(CSync -> Y, Red -> Pr, Blue -> Pb)

[grips03]

Albino I tried 1 Genesis and 2 SMS and get same results for all three. Getting TG16 this week and will RGB mod it, but so far Saturn, SNES, N64, DC all work.

[grips03]

In the Sony manual it says, "This TV's PC input does not support Sync on Green or Composite Sync. This TV's PC VGA input does not support interlaced signals."

Perhaps this is what the XRGB2 sends when connected to Genesis/SMS?

[acem77]

I could test the cable for you on my xrgb2+.