What's new
By:

Sega Model 2 and Model 3 Filter Board Pinouts

twistedsymphony

twistedsymphony

Enlightened
Staff member
Immortal
Joined
Jul 21, 2015
Messages
12,345
Reaction score
14,684
Location
NH, USA
Original Post on my blog: http://solid-orange.com/1273

I recently needed to convert a Sega twin unit arcade machine that had model 2 boards to one that used model 3 boards. I found it really difficult to find information on which pins do what on the filter boards so to get my head around how to change the wiring I made my own diagrams since none seemed to exist.
Model 2A, Model 2B/2C and Model 3 all use the same connectors for everything except for power. the only difference is the connector locations. The power connectors that have a line through them are for output; typically used to power another board somewhere.

sega_model2_a_pcb_arcade_filter_board_pinout.gif

sega_model2_b_c_pcb_arcade_filter_board_pinout.gif

sega_model3_pcb_arcde_filter_board_pinout.gif

These are based on what I could gather from manuals available online and what I could meter on the boards that I have.

if you discover any errors please let me know.
 

Attachments

  • sega_model3_pcb_arcde_filter_board_pinout.gif
    sega_model3_pcb_arcde_filter_board_pinout.gif
    63.3 KB · Views: 705
Last edited:
I only have Model 3 games. I will check pinout I use.

Could you list what parts you have to cgange to convert a Model 2 to Model 3 cabinet ?
 
Gakman said:
Could you list what parts you have to change to convert a Model 2 to Model 3 cabinet ?
Click to expand...
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.
 
Nice work- looks good to me offhand- I'll have to check- but it's really nice that Sega made every plug a different size- and that technically it doesn't matter if you power through in or out (at least on the model 2 A/B versions) as they're all connected on the backside of the filter anyhow, just as the naomi IO is.

Any chance you have some numbers for the actual current for each, 5v and 3v?

I also run my model 2's outside of their enclosure without a fan- they stay plenty cool inside a candy cab under extended use, but I can see how a dedicated cab would be better off with the enclosed chassis.

Also If you run them without an enclosure and have a few different games, I'm a fan of recommending redoing the standoffs- if a proper set is used (I got mine from eBay...) the rom boards can be easily swapped without having the disassemble the entirety of the stack.. as I have 5 or 6 different model 2 games, this comes in handy...
 
defor said:
Any chance you have some numbers for the actual current for each, 5v and 3v?
Click to expand...
Aside from knowing what the model 3 PSUs output spec are (+3.3V:12A, +5V:7A and +12V:2A) I don't have any real-world current draw numbers. Though I'd suspect it changes depending on equipment. For instance I noticed that Model 2 games without the comm board typically have one fewer 5V inputs populated on the filter board.

defor said:
I also run my model 2's outside of their enclosure without a fan- they stay plenty cool inside a candy cab under extended use, but I can see how a dedicated cab would be better off with the enclosed chassis.
Click to expand...
in a Twin unit the enclosure is definitely needed, there was several pounds of sand in my cab when I first got it and even with home use only for the last few years when I cracked it open to work on it there was quite a bit more in there... and it all dumps on top of the game board since that's where the seam in the floor boards are for maintenance access.
 
Finished building and metered out my conversion harnesses last night and double checked the pins on these boards. I had the Model 3 audio connectors and the fan connector upside down (pin numbers were correct but the positions on the diagram was 180*) the diagrams have been updated to correct this.
 
Just picked up a Virtual-On rom board and was curious if the the model 2 a/b/c filter board pinouts were different. Thanks for the putting this together.
 
Pretty sure it's the same, for VO on model2, both players inputs are used, each for one stick of course.
 
mr_b said:
Just picked up a Virtual-On rom board and was curious if the the model 2 a/b/c filter board pinouts were different. Thanks for the putting this together.
Click to expand...
VO is the reason I made these pinouts :)

I have a USA VO Twin unit and I upgraded it to Model 3 VOOT, I got so frustrated with all the shitty half-complete bits if information online that I made these diagrams for my own benefit, and then decided to finish the job by doing the Model 2 A-CRX as well as all the other connectors.

-------
VOOT is designed for the B-CRX board with the communication board equipped (though I'm not sure if it's necessary to boot).
The way VOOT is wired the left stick is wired to player 1 joystick up, down, left, right, and buttons 1 and 2, and the right stick is wired to player 2 up, down, left, right, button 1 and 2.

The start button is of course wired to player 1 start.

output 0 on CN14 supports a start button lamp. and I think one of the other pins supports a "Winner" Lamp as well (Not entirely sure which one since the Twin unit cabs isn't wired for it)
 
Question ?

If possible to modify a Model 3 Filter Board for Model 2 to enjoy Video VGA Output or Modify a Model 2 Filter Board with VGA Output?

And or to go even further creates a Filter board like that of the Naomi for a Model 2, 1 or 3. :thumbup:

Bye Bye All the wires with lots of noise for audio and video LOL :rolleyes:
 
i didnt think m3 had vga output.
your not confusing the fact it has a 15way mini-D with the sync-rate are you?
 
chacal231077 said:
If possible to modify a Model 3 Filter Board for Model 2 to enjoy Video VGA Output or Modify a Model 2 Filter Board with VGA Output?
Click to expand...
Model 3, despite using a VGA connector, was still only 24KHz "Medium Resolution". Not to mention that the filter board doesn't do any signal processing. it's just a dumb pass-though board. you could technically run the games without it if you had the right connectors.

The connectors for everything except power (which are only different because Model 3 uses 3.3V and Model 2 uses 5V) are identical between model 2 and model 3 so there's no benefit to swapping them (they're internally pinned completely differently anyway so it'd be a huge amount of work for ZERO benefit).
 
Thanks for posting that. I used this thread just a few days ago to hook up my new Supergun to my 2 model2b boards. Though the harnesses were manufactured differently than I wanted, I still managed to powerup and get video. I elaborate a little further on this in the Model2 Jamma harness thread here: Model 2 to JAMMA harness
 
Sega Super GT. I am using an empty Outrun 2 cab to convert into Super GT, and I am looking into using board features to add game-controlled lights and stuff.
 
HI

I need your help :)

I have a Sega model 2A filter board, that I want to convert to a Sega model 3 filter board, so that I can use it as a test rig to hopefully find my video fault one one of my model3 video boards.

As I can understand I need to change one of the three 5v inputs to a 3.3v input.

But there is three 5v connectors at the 2A filterboard CN1, CN3 and CN12 witch one of this do i need to change to 3.3V?
 

Attachments

  • Model 2A filterboard 5v inputs.JPG
    Model 2A filterboard 5v inputs.JPG
    270.3 KB · Views: 783
You must log in or register to reply here.
Back
Top