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

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



      Look at this thing! Look at it's glorious games!
      How in the hell do I wire one of these up?

      Well that's why I started this thread... I'm a n00b and wanna learn. Lets learn together.

      I bought a Model 2B CRX and know nothing about it outside of that it looks like it's a thicc stacked juicy burger of sexy PCBs from SEGA .
      These metal burger bath-tubs always intrigued me, and to say the least within a year or so, I'd love to assemble my own Model 2/3 SEGA multi driving setup, or perhaps collect a couple unreleased titles.



      It didn't occur to me how complex these seem to be, and can be quite imposing when you unpack it and go WTF.
      I hope you're a glutton for punishment...
      s


      What do I do now?!?!?!
      With that said I'm moving my information thought dump here so I can ping you good folks for help.
      Now as it stands there's multiple ways of connecting this thing up.
      (Yes I know there's other sub threads in other places, but this is now in one place)


      Edit



      Don't make me hit a bitch with a Blast City!!!


      What are my options??? Jamma? JVS??? Japanese Harnesses???? LOLWUT?!?!

      Blast city harness... I have a Blast City Cabinet.
      page.auctions.yahoo.co.jp/jp/auction/k374885579

      "I've never understood why wire is so expensive." @twistedsymphony

      part number 600-6738-20
      I'm not sure if model 2 got it's own loom, but they're nearly identical
      the top section plugs into your board, and the bottom section plugs into the Blast's IO board,

      Then I saw this thing from Hong Kong...
      ebay.com/itm/Sega-Harness-Mode…Board-28-Pin/182049587191

      Interesting and I'm sure it'll work with most units.


      Also, here's a nice compendium of VOLTAGE Differences and Notes:
      The biggest difference is that Model 3 requires 3.3V power (similar to newer JVS boards) while Model 2 only uses 5V so the power supply will need to be upgraded to a model that provides a 3.3V power source.

      There are really 2 connections that need to be changed when going Model 2->Model 3.
      1. The Main Power Connector:
      Model 2 has 3 10-pin connectors for 5V power, 5 pins for 5V, 5 pins for ground on each of these (CN1, CN3 and CN12 on M2A and CN9, CN10, and CN11 on M2B/M2C).

      Model 3 uses one of these 10-pin connectors for 5V power (CN14) and also has a large 24 pin connector (CN13) that includes 8 3.3V lines, 6 5V lines and the rest of the pins are ground. you could re-pin one of the 5V connectors from model 2 to populate half of this connector and then fill out the rest of it with fresh lines for 3.3V. In my case I'm leaving the two extra 5V connectors from Model 2 disconnected and simply adding a whole new connector for the 3.3V/5V connectors that Model 3 requires so that I can easily swap back to Model 2 if I so choose.

      2. The Fan Connector:
      Model 2 has an externally mounted 12V case fan that uses a 2-pin Molex connector going directly to the fan (not in the diagram), Model 3 has 2 internally mounted 12V case fans that receive their power through a 3-pin JST NH connector on the filter board (CN16). For this I made a simple adapter cable with a 3-pin NH connector on one end and a Molex connector on the other end. This makes it plug and play, and keeps me from having to run new 12V wires while reducing the number of unused connectors.

      *A Note about the 5V output connectors
      Model 2B/2C and Model 3 all use the same 11-pin connector for 5V output (the additional pin makes it easy to tell apart from the 10-pin input connector). Model 2A has a 11-pin 5V output connector too, however Model 2A also has an additional 9-pin 5V output connector. that the later boards are lacking. This seems to be the biggest compatibility difference between Model 2A and 2B/2C.

      All other connectors should be pin-compatible.

      I will say that the audio connectors were listed has being pinned differently in nearly ever manual I cam across, even the audio connector on one of my Model 2 boards (just one) was plugged in backwards, which I confirmed by metering out the ground pins. so I'm least confident in that connector (though worst case is they L and R are swapped or it's out of phase).

      Most pinouts for the 25-pin digital control connector that I found online were wrong when compared against the service manuals and against my own machine wiring. so it would be nice to get confirmation on that connector from another working setup.


      ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

      Footnotes:

      I got a lot to put here, but if you have anything else of use, go ahead and toss it in.
      I can't seem to source manuals or wiring diagrams for most of this stuff.
      Thank you for @twistedsymphony for piquing my interest in kicking the tires on one of these.
      Videogame Historian
      Bench : Genesis 2 Jamma 6-Button
      WANT : Irem M92 | Fallen Angels Daraku Tenshi
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    • Well you've got an information dump for the Model 2 side of things... but here's what you need to know about the Blast City Side of things:
      wiki.arcadeotaku.com/w/Sega_Bl…Guide#Cabinet_I.2FO_board

      basically you just need that, my model 2 diagram, the parts and some time
      Buy 3D Printed Parts: bit-district.com
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    • it looks like you have a Model 2C PCB so all you really need is this pintout:


      and then match all of the pins to the pinout here: wiki.arcadeotaku.com/w/Sega_Bl…Guide#Cabinet_I.2FO_board

      the rest of the information in your "dump" is just noise.
      Buy 3D Printed Parts: bit-district.com
      Projects: instagram | blog
      Games: VAPS | VOOT | UMK3 | RFM | Vewlix | FiF Jr. | KI2 | E29 | Net City | DDR | Flash Beats
      Wanted | For Sale/Trade
    • twistedsymphony wrote:

      it looks like you have a Model 2C PCB so all you really need is this pintout:


      and then match all of the pins to the pinout here: wiki.arcadeotaku.com/w/Sega_Bl…Guide#Cabinet_I.2FO_board

      the rest of the information in your "dump" is just noise.
      Well, I'm far from done, but i'll be using this space to mess with.
      With concern to trying to also build a harness for a supergun, all of this will prove useful.
      Thank you for the help and pointing the way.
      Videogame Historian
      Bench : Genesis 2 Jamma 6-Button
      WANT : Irem M92 | Fallen Angels Daraku Tenshi
      [astrocity] InstaGram [neogeo] My Arcade Projects Photoblog [saturn] My VAPS PCBs [nes-101] My Twitch Channel