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Can I objectively say that I have a JAMMA and not a JVS cabinet

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freekiefae

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The discussion here (https://wiki.arcadeotaku.com/w/JVS) is a bit confusing:

JVS, or Jamma Video Standard (sometimes even called JAMMA 2), is a specification by a JAMMA special sub-committee consisting of the major arcade game manufacturers. JVS specifies the type of connectors to use for video (HD-15), audio (RCA) and power (JST_VL), in addition to the communications protocol between the game board and the I/O board. In contrast to (old) JAMMA, JVS concentrates I/O functions in a separate board.

I've got this specs section of the manual:
1707356667809.png

This is what my PCB actually looks like:

JAMMA-B.jpg



Normally, I would look at that board and giant JAMMA on the bottom edge and order the JAMMA accessories. But the Okatu description confuses that by saying that JVS is an evolution of JAMMA, and the manual description just says they are both "compatible".

Please advise.
 
You got one of these in your cab?

IMG_5058.png


Then you have a jamma cab.

That pcb enables a jvs game (in this case a namco 246 or 256) to run on a jamma cab. It’s called a JVS i/o since it takes jamma on one side (your cab’s jamma harness) and JVS on the other (a jvs compatible game)
 
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What cab do you have? Stating what cab it is would definitely give you an answer.
 
I apologize for skipping that detail. I have a Soul Caliber II (rev D) cabinet. It's running on a 246 like ekorz deduced.

I definitely have one of those massive harnesses coming off the Happ Controller.
 
Namco loves to make stuff no one else can use: The "jvs" card you have has a proprietary connector that only fits the 246/256 system.
On the other hand, the 246/256 system has that proprietary connector AND a more standard "usb physical connector" used for JVS protocol, that can be used with other JVS cards.

I'm assuming that proprietary connector is just a different physical connector to pass the JVS protocol. Anybody can confirm that?
 
What monitor do you have in it? If it has a 31khz only monitor, I wouldn't call it a "jamma cab".
 
You know here in the UK operator's never understood the JVS standard & thought cabs such as the Naomi Universal were game locked & scrapped them well before end of life.
 
freekiefae said:
The discussion here (https://wiki.arcadeotaku.com/w/JVS) is a bit confusing:

JVS, or Jamma Video Standard (sometimes even called JAMMA 2), is a specification by a JAMMA special sub-committee consisting of the major arcade game manufacturers. JVS specifies the type of connectors to use for video (HD-15), audio (RCA) and power (JST_VL), in addition to the communications protocol between the game board and the I/O board. In contrast to (old) JAMMA, JVS concentrates I/O functions in a separate board.

I've got this specs section of the manual:
1707356667809.png

This is what my PCB actually looks like:

JAMMA-B.jpg



Normally, I would look at that board and giant JAMMA on the bottom edge and order the JAMMA accessories. But the Okatu description confuses that by saying that JVS is an evolution of JAMMA, and the manual description just says they are both "compatible".

Please advise.
Click to expand...
When I got my Tekken 4 in 2010, I too was confused by this style board as Namco deemed this a JVS style. Here is where lies the confusion. The bottom pins are JAMMA 1. BUT! Namco tried to use JVS VL and for that (small back slot for ribbon cable) , allowed them to claim JVS. Pretty dumb concept. If I remember, Namco was one of the biggest drivers pushing JVS along with Sega.
 
ekorz said:
That pcb enables a jvs game (in this case a namco 246 or 256) to run on a jamma cab. It’s called a JVS i/o since it takes jamma on one side (your cab’s jamma harness) and JVS on the other (a jvs compatible game)
Click to expand...
technically not that one. Sys2x6 does support JVS but the JAMMA IO doesn't use it, rather the inputs are sent over a ribon cable directly to the mobo, bypassing JVS entirely.
 
twistedsymphony said:
technically not that one. Sys2x6 does support JVS but the JAMMA IO doesn't use it, rather the inputs are sent over a ribon cable directly to the mobo, bypassing JVS entirely.
Click to expand...
Are you saying that ribbon cable interface could go directy to jamma?
 
nem said:
What monitor do you have in it? If it has a 31khz only monitor, I wouldn't call it a "jamma cab".
Click to expand...
This to me is the important question to answer.

Your i/o won't mean much if you're trying to pass a 240p signal to a 31khz monitor.
 
Thanks Aurich!

I think this SC II manual was just written by someone that wanted to give vague, double answers to everything. It would seem the answer is "both":
1707528287666.png
 
For whatever it's worth, The PCB supporting the monitor has this written on it "NEOTEC NT-500 DXOC01", I've googled it some. It seems they are prone to their own variety of issues, but seems to be operating in VGA mode well enough for me to play.

edit: I got a lot of additional perspective from this video posted by Mike's Arcade repair:
View: https://www.youtube.com/watch?v=D7MMpJiJBCg


I would love to hear if anyone has experience dealing with Mike. In this video, he does specifically state that the CGA/EGA is part of the 15 kHz output. So, I'm guessing the VGA has to be the 31kHz.
 
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Mrhide said:
Are you saying that ribbon cable interface could go directy to jamma?
Click to expand...
no, but it's not JVS either, it's some proprietary connection. If you trace the pins half of them go to the Altera CPLD, If I had to guess it's either using simple multiplexing, or the Playstation controller protocol.
 
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JVS games/cabinets use a USB (JVS) cable for I/O, stereo RCAs for sound, VGA cable for high or low resolution video, and JST-VL connectors for power (which includes 3.3v).
Jamma games/cabinets use a Jamma harness for controls, mono amplified audio, predominantly low resolution video, and power.

This is a 246/256 with the Namco Jamma adapter. It's 246/256 specific and can't be used just for any JVS game. If your cabinet is using the board it's a Jamma cabinet.
system246-2.png


Also 246/256 is not strictly JVS as it doesn't have a JVS power connector (requires an adapter) and doesn't require 3.3v. Low and high res video are selectable via a dip switch. It also has USB ports on it in addition to the JVS usb port for IO, so don't mix those up.
 
freekiefae said:
Thanks Aurich!

I think this SC II manual was just written by someone that wanted to give vague, double answers to everything. It would seem the answer is "both":
1707528287666.png
Click to expand...
Okay good. By "selectable" it probably means there's a physical jumper you need to move to connect the proper pins to switch which resolution you want. So keep that in mind, if you're running 31khz now over the VGA cable, and you want to connect a jamma game, you need to move that jumper to support the 15khz resolution that game will need.
 
Thanks all!


If I am getting all of this right, the 246/256 is in some senses "a JVS", but with some big caveats. For the purposes of converting my cab to a MAME/MiSTer set-up, it seems lowest effort to engage at the JAMMA connector which is right next to the word JAMMA on that PCB. So, hypothetically, these two links would both be compatible ways to go for this cabinet:

MiSTercade
https://www.arcade-projects.com/threads/misteraddons-mistercade-mister-for-jamma-cabinets.19382/

MiSTer JAMMA Expander
https://www.arcade-projects.com/threads/irken-mister-jamma-expander.16915/

OR, if I really wanted to use the VGA out, then I could grab something like:

MiSTer JVS Expander
https://www.arcade-projects.com/threads/irken-mister-jvs-expander.23214/
(This is NOT compatible with my particular cab due to the power disagreement that notsonic pointed out. Thanks @notsonic .)

OR, OR, if I needed to be "budget friendly" on the adapter and have an obsolete PC to through at this I could do something like the J-PAC, or J-PAC 2.
 
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The video I posted talks about the jumper in detail, right about 7min and 15 sec.

It's about the only point that Mike makes with much clarity in the video. Everything else is discussed with some assumed knowledge of the trade or the components.
 
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