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Sega Model 2/3 A/B/C - CRX and how I stopped worrying and learned to love the bomb.

If you just want it to work, grab a Gonbes. They're not great upscalers, but they will work with Model 2 / 3. Plus, they're dirt cheap.

OSSC on the other hand can be troublesome if you pair it up with the wrong monitor.
 
OK so if I grab a Gonbes (which I see Focus Attack carries) and then I go to Amazon and buy a VGA screw terminal (pictured below), then I just need to do the 5 wire pinout.

So would the correct pinout from the CN3 port on the Sega IO Board to the VGA terminal be something like this:

  • RGB Red → PIN 1
  • RGB Green → Pin 2
  • RGB Blue → Pin 3
  • RGB Sync → Pin 13
  • RGB Ground → Pin 10

Or did I look up the wrong pinout guide?

Screen Shot 2021-02-17 at 4.26.41 PM.png
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81NyuRAx2EL._AC_SL1500_.jpg
 
Wow, so playing Model 3 boards via Supergun sounds really complicated.

Guess the best way to play this is via blast city with a dedicated model 3 PSU?
 
klee123 said:
Guess the best way to play this is via blast city with a dedicated model 3 PSU?
Click to expand...

The stock PSU will handle Model 3. You just need the harness for it. But yeah, it is very convenient for the handful of stick and button games.

aphonia said:
So would the correct pinout from the CN3 port on the Sega IO Board to the VGA terminal be something like this:
Click to expand...

That looks correct, yes. Connector series is JST NH.

As for video input, I used the 5-pin video connector on the GBS8200, however, according to the manual it should be fine to connect it to the DE-15 ("VGA") connector too.

Model 3 also has a DE-15 video output connector, I wonder if you could just use a regular VGA cable from the Model 3 to the Gonbes?
 
nem said:
The stock PSU will handle Model 3. You just need the harness for it. But yeah, it is very convenient for the handful of stick and button games.
Click to expand...
Hmm, if I wanted to play this via Supergun on TV, will I need a Sega IO board?
 
nem said:
That looks correct, yes. Connector series is JST NH.

As for video input, I used the 5-pin video connector on the GBS8200, however, according to the manual it should be fine to connect it to the DE-15 ("VGA") connector too.
Click to expand...

Thank you for that info. I super appreciate everyone's help here. I feel like I'm so close to making this work so really happy about that.

So that is the same GBS8200 I saw at Focus Attack so I'm gonna put an order in now for one. If my VGA 5pin wiring idea doesn't work, I do have a quick follow up question (hopefully my last question). I see that 5 pin connector spot on the GBS8200 board that lines up exactly with the Model 2 board with RGBGS. But what is the name of that connector so I can buy one of those from amazon as well? It kind of looks like a power supply adapter? Is there an official name I can look up for that head so I can quickly order it from amazon?

Thanks again everyone!


Edit: Would this be the right cable? Not sure if the spacing is correct for that 5pin connector on the board without seeing it in person. https://amzn.com/B07D8QCZQL
 
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Awesome and thank you. I didn't realize it's just called an EGA Signal Input cable, lol. I was looking for Molex cables and all kinds of stuff. Thanks again!
 
aphonia said:
Awesome and thank you. I didn't realize it's just called an EGA Signal Input cable, lol. I was looking for Molex cables and all kinds of stuff. Thanks again!
Click to expand...
When i wrote « if you buy one » i meant if you buy a gbs8200, not the ega cable
 
So I got my GBS8200 this morning. It unfortunately did not come with that 5 pin EGA cable. So I've tried hooking it up with my custom made 5 pin screw terminal DB15 head and then using the DB15 input on the GBS8200. It does work, but about 15 seconds of use the, blacks start to fade and become a purple'ish hue and throws off the color completely. Also took me a bit to get the menu system built into the GBS unit to English to make some other adjustments.

I don't believe it to be an in issue with my Sega Motherboard or IO. Because when I had the original sync issue, the colors were perfect. Just of course I couldn't play with the Vertical issue.

So I've narrowed it down to either my cable I made (either the pinout not being correct, or something with the wiring). Or the GBS unit's VGA input or VGA output isn't that great to begin with and this is a familiar problem. I am going to wait to see if the 5 pin EGA cable will work. Even though @Mrhide you did mention it should have come with that cable, I had ordered another one from Amazon, and it's expected to be here by the 26th according to them. So gonna try the direct 5pin cable from the Sega IO Board to that input and see if the same issue happens. If I still get the Purple Hue, then it's either just a bad board either on the input or the output. Unfortunately there is only one output through that VGA port so I can't test any other way to get the signal out.

If anyone else has any suggestions on what to check in the meantime while I wait for this cable/adapter, I'm all ears. Again thank you to everyone in advance for all your help.
 
Play with the coast and clamp settings.
I had that happening too.
Coast st 03
Coast sp 04
Clamp st 03
Clamp sp 04
 
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WOW @Trol that totally worked when I set my Clamp to 03/04. I only had the Clamp ST and SP, I could not find a Coast setting. But that fixed it completely. My values were default set all the way to like 90 each. As I was going down in value all the way to 3 and 4, the image turned completely off and was thinking to myself, what is this even doing. Then as soon as it hit 04 on Clamp SP, the image came back and the purple hue was gone. I was shocked and confused LOL. So thank you again @Trol.

But my follow up question is. What does this CLAMP setting even mean or do that fixed it? I was trying to find a manual to see what it means but couldn't find one. Just other people saying to adjust it in other forums. I would have never guessed to mess with that option (especially that major of a change).

I am still gonna wait for that other cable to come in to see if I can make it look cleaner to this board. But overall this has been one heck of an experience and I can't thank everyone enough that helped with getting this up and running. So happy to have it running fully. Now to find other Model 2 games LOL.

Thank you everyone. Thank you for the pinouts from the very first post, to everyone that recommended a part or confirmed something for me. Stay Safe and try to Stay Healthy out there!
 
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I dont know what it means either:)
Remember reading it in the manual or online...important thing is thats it works
 
Another quick question as I couldn't find a definitive answer.

If a game is a Model 2A game, will it work on a Model 2B motherboard (CRX-B)? Or does it have to be 2A game to a CRX-A and a 2B game only works on a CRX-B board?
 
aphonia said:
have to be 2A game to a CRX-A and a 2B game only works on a CRX-B board
Click to expand...
^THIS

Mostly though it's just the program ROMs that are different.

So for instance Zero Gunner was released on both CRX-A and CRX-B you can move all of the ROMs and the security board over to the other hardware, and then burn new Program ROMs.
 
OK, but to keep it simple if the game didn't come on both, I can't just connect the CRX-A game board to a CRX-B motherboard.
 
Loving this thread. Well, I bought a Harley-Davidson LA Riders (Model 3 Step 2) from a trusty arcade shop in China (hasn't shipped yet) that I bought a Scud Race subwoofer from, alongside the original cabinet's wiring harness which I've already got, and wanted to ask general stuff about the possibility of hacking console controls to play it with. It's another driving game but doesn't have additional MPEG audio or force feedback, and my favorite of the Model 3's library next to Daytona 2. I'm pretty new to owning arcade hardware so any advice would be greatly appreciated here!

My goal is to try splicing parts of the harness with a Dreamcast racing wheel -- a Pelican-brand "Rally 2" wheel, which has no pedals but analog triggers with what appears to be 3 potentiometers for brake, gas and steering. The LA Riders game uses 4 but I want to sacrifice the Front Brake for the Rear Brake pedal control. As I've seen other people use the official DC race controller with Scud Race (minus manual transmission), would it be a means of crimping or soldering the appropriate wires from the DC wheel to where the wires are going onto the PCB? Are there extra common grounds involved? This particular game is difficult to find a wiring diagram for because it's one of the less-popular Model 3 titles, but I was wondering what connectors I'd be looking for in the harness to make my inputs from the wheel work on Model 3. I did see useful diagrams on shared on Arcade-Otaku of the M3's wiring and connections, though, like this one:
C23H51o.jpg


I looked at CN1 on my Harley harness and there's another wire going to pin 9. I wonder if that's the rear brake...

Also attached is a pinout of the wiring that goes to the DC wheel's circuit. Ignore CN6 which is for the vibration motor, and CN1 as that is for the VMU slot. This wheel is additionally very clean, plus easy to open up & understand, so I was wondering if it's possible to wire this wheel to play Model 3 drivers. Thanks in advance! ;)
(There is a little glare on the photo, but the SH I think is for the vibration motor. The wires soldered directly to the circuit are for the steering hence 'X')
 

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  • DC Rally 2 wheel pinouts.jpg
    DC Rally 2 wheel pinouts.jpg
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Use the pinout on the first page... CN1 and CN11 are used for analog control.. as for which input is mapped to which analog channel I'd recommend just hooking up a pot to the different pins and seeing which is which in test mode.
 
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