Console SCART to Arcade/JAMMA - How does one get a Simple PCB to be Fabricated?

[donluca]

Whatever you do, please try to use only through hole components, no SMD as those are a pain in the butt to solder.

If you're stuck with SMDs, try at least to give fingerboards with those components already soldered.

 

[Lemony Vengeance]

The solution I plan on designing will be completed, minus the controllers. No component construction will be needed on the end user’s part.

Pad hacks are a necessary evil, and I’ve gotten it figured out so that it will be as easy as possible to connect them

 

[donluca]

Well, you might include some very basic control inputs, like Master System/Mega Drive ones which are really easy (no component or a single chip).

 

[TheLastBandit]

Well my newest batch of Jammacon pcbs arrived today so I've no plans to modify my design in the near future anyway.

Maybe whoever makes the MC Chuthlu board could make a version with a compatible footprint to fit my board as it looks like a good solution?

Seems like ye have everything in hand coming up with an alternative design so not sure if I can be of any help.

 

[RealMFnG]

Well my newest batch of Jammacon pcbs arrived today so I've no plans to modify my design in the near future anyway.

Maybe whoever makes the MC Chuthlu board could make a version with a compatible footprint to fit my board as it looks like a good solution?

Seems like ye have everything in hand coming up with an alternative design so not sure if I can be of any help.

Stick around. You'll like this forum. Plus since your solution is available now, there may be those interested. Go introduce yourself and welcome aboard!

 

[RealMFnG]

Lemony, on a related note:

• Encircled in RED, is this for JST NH series connectors? What series connector or spacing are these thru-holes?
• Encircled in BLUE, what JST series connector for these thru-holes? Or what is the spacing for these?

Thanks!

 

[RealMFnG]

I got a response from Tim Worthington. He gave me blessing to post here what he wrote to me on the email. But I feel there is sensitive info on that email. So I'll let him reply to my response again before I do (full disclosure). Seems he is having difficulty with getting an account here. Hope he can solve that and join the discussion.

 

[wigsplitta]

Well my newest batch of Jammacon pcbs arrived today

I've got one of these with the SNES, Megadrive and Playstation daughter cards. Works like a charm with lovely picture quality. I'd thoroughly recommend to anyone who wants a nice, simple plug and play setup.
I saw mention of a possible Dreamcast card in the future...that'd be an instant purchase by me

 

[RealMFnG]

I've got one of these with the SNES, Megadrive and Playstation daughter cards. Works like a charm with lovely picture quality. I'd thoroughly recommend to anyone who wants a nice, simple plug and play setup.
I saw mention of a possible Dreamcast card in the future...that'd be an instant purchase by me

I am going to hold out and see what Lemony comes up with. I really like the Jammacon w/the Pad hack board. Would suit my needs almost perfectly. My only gripe is that all video must be passed thru SCART to get to JAMMA 15khz standard via the edge connector. Wish he had a secondary connection for video sources that already output perfectly to the JAMMA standard (Dreamcast and a MAME PC for example) that would simply allow pass thru to the JAMMA connection.

I feel devs for these Console-2-Jamma boards should skip trying to interface console controls. Just let the PS360+ or MC Cthulhul handle it as these things do it better simply because the console compatibility is more inclusive; rather provide interface connections from the multi-console PCB's via screw terminal, JST headers, or 2x10 header connection. Seems Lemony is hinting at this. Also, just focus on SCART and passthu for video connections. SCART is the closest to JAMMA video standard and would provide the least generation loss from console video to JAMMA standard. Anyone attempting to do this is going to be a snob. So they want the best video quality. No need to convert composite video, S-video, component, RF, or whatever to JAMMA 15khz video. Assume those in the market for a console-to-JAMMA interface will concede the need to acquire a SCART cable for whatever console they are interfacing to JAMMA. As for audio, while all doing this will be snobs, these snobs vary in technical proficiency. Some won't know how to wire their JAMMA standard cabs to stereo. So in that case, leave by default the ability to downmix from SCART audio to JAMMA audio through the JAMMA connector. Maybe and a jumper to switch to line level external output to a stereo amp.

Let's face it, there are only so many consoles that any arcade snob would interface to a low res 15khz monitor. Because once you start interfacing an HD capable console to a low res display device, you would be doing the games you are trying to play a disservice. So that means, from descending order, here are the consoles you would want to interface to JAMMA (I've added one killer ap from each of these consoles I would love to play on an arcade setup):

Wii - Tatsunoko vs Capcom
OG Xbox - Panzer Dragoon Orta
Gamecube - Smash Bros
PS2 - Gradius V
Dreamcast - Sturmwind
PSX - Einhander
Saturn - Macross DYRL
N64 - No games I want to play on arcade cab since most N64 games have analog controls
PSX - too numerous to count
PCE/Genesis/SNES - all the shmups
NES/Master System - not sure If I want to play these games on a arcade cab

 

[TheLastBandit]

I am going to hold out and see what Lemony comes up with. I really like the Jammacon w/the Pad hack board. Would suit my needs almost perfectly. My only gripe is that all video must be passed thru SCART to get to JAMMA 15khz standard via the edge connector. Wish he had a secondary connection for video sources that already output perfectly to the JAMMA standard (Dreamcast and a MAME PC for example) that would simply allow pass thru to the JAMMA connection.

Its not more complicated to wire a cable with a SCART plug than to a other connector type and SCART also allows for audio input and are available for every console capable of outputting RGB. I think there are already better solutions for hooking up PC's to cabs.

I feel devs for these Console-2-Jamma boards should skip trying to interface console controls

Nope. Part of the enjoyment of designing these is figuring out everything including the console controls. For a mass market product, ya if there is a cheap plug-in module that does the job the absolutely go for it.
Also for support issues, its much easier if your the owner of the whole product.

Wii - Tatsunoko vs Capcom
OG Xbox - Panzer Dragoon Orta
Gamecube - Smash Bros
PS2 - Gradius V
Dreamcast - Sturmwind
PSX - Einhander
Saturn - Macross DYRL
N64 - No games I want to play on arcade cab since most N64 games have analog controls
PSX - too numerous to count
PCE/Genesis/SNES - all the shmups
NES/Master System - not sure If I want to play these games on a arcade cab

All of these are already playable with my solution, by combining the PSX adapter with 3rd party converters.

 

[RealMFnG]

Its not more complicated to wire a cable with a SCART plug than to a other connector type and SCART also allows for audio input and are available for every console capable of outputting RGB. I think there are already better solutions for hooking up PC's to cabs.

Point here is there is generation loss converting from SCART to 15khz RGB. Screw terminals with pass through to the JAMMA connector would allow for the conversion from SCART to be skipped when possible.

Nope. Part of the enjoyment of designing these is figuring out everything including the console controls. For a mass market product, ya if there is a cheap plug-in module that does the job the absolutely go for it. Also for support issues, its much easier if your the owner of the whole product.

Ahh yes, good point. Must be fun. Wish I had the skills. And understand the need for control of the product.

All of these are already playable with my solution, by combining the PSX adapter with 3rd party converters.

Yup. I dig your product with the pad hack board. Only thing missing is the screw terminal thing for pass through. Not in a rush, so will see what Lemony comes up with. Then evaluate and hope you have units left if I decide to go with yours.

 

[TheLastBandit]

Point here is there is generation loss converting from SCART to 15khz RGB. Screw terminals with pass through to the JAMMA connector would allow for the conversion from SCART to be skipped when possible.

But this conversion needs to happen to correctly 'match' the differing video signals. Consoles and arcade monitors has different signal voltage ranges and biases, the amplifier I use outputs the correct signalling for the arcade CRT so there is no picture degradation.

 

[Lemony Vengeance]

Lemony, on a related note:

• Encircled in RED, is this for JST NH series connectors? What series connector or spacing are these thru-holes?
• Encircled in BLUE, what JST series connector for these thru-holes? Or what is the spacing for these?

Thanks!

Red is NH, blue's pitch is 2mm, so I believe it will work with the PH series header.

I'm not designing a supergun, so adding things like console controller sockets is right out (if that comment was even meant for me). It wouldn't work that way anyway.

 

[RealMFnG]

I'm not designing a supergun, so adding things like console controller sockets is right out (if that comment was even meant for me). It wouldn't work that way anyway.

S-S-S-S-OO-PER-GUN, super-gun. Supergun? What is that for? Shooting superheroes? That word isn't in my lexicon dawg .

As we wait for what ever you are coming up with, do you ballpark price in mind for how it you will be selling it for?

 

[Lemony Vengeance]

I'm not designing a supergun, so adding things like console controller sockets is right out (if that comment was even meant for me). It wouldn't work that way anyway.

S-S-S-S-OO-PER-GUN, super-gun. Supergun? What is that for? Shooting superheroes? That word isn't in my lexicon dawg .
As we wait for what ever you are coming up with, do you ballpark price in mind for how it you will be selling it for?

no ballpark price :/

 

[RealMFnG]

Alright @Lemony Vengeance, can you reveal your trade secret and let us know what circuit you are using for video amplification? How are you achieving automatic brightness and attenuation from RGB scart from the console to RGB for the CGA monitor?

 

[RealMFnG]

It's not that easy.

Consoles output an AC coupled video signal while arcade monitors expect a DC coupled one.

In layman terms, this means that the brightness will change depending on what's shown on screen due to a missing voltage reference.

A video amp is not enough, you'll have to build a clamp or a DC restoration circuit to achieve a good and stable picture on your monitor.

I've been scratching my head for at least a year and had a semi-working project but had to give up due to time/money issues.

I still have most of the components needed, but will is lacking, have other stuff to do, blah blah blah.

Maybe one day I'll get back to it.

Hi @donluca,

Your post has stuck with me ever since. Wanted to ask you what consoles in your experience output this AC coupled video signal that would degrade brightness?

The reason I ask is that I have been fiddling with the PS1, PS2, and Saturn over the past week and haven't run into any issues. I am simply using the RGB signal via SCART cables from the consoles, plugging that into a sync stripper, then feeding R, G, B, CSync, VGround into my arcade monitor. So far, this has been successful on a Wells Gardner K7000 and a NeoTec NT-33c. I suspect though that the limited sample I have won't hold true with all games. But I feel the Saturn should be fine and not ever have this problem. Same also for the Dreamcast that I will later play around with. But the PS1 and PS2 might run into these issues, although both seem to be working fine in the setup I described. I just feel this way because of some experimentation with Sony's consoles from years earlier.

If I try this with 16-bit consoles and earlier, is this where I should expect to run into this problem you speak of?

 

[donluca]

Unfortunately, it's not a simple issue of "degraged brightness".
The problem is that the brightness of the image varies based on its content because the monitor is expecting a fixed voltage across its RGB lines (which is how DC coupled video signals work) and instead the voltage fluctuates due to not having a reference voltage.

This is true for all the consoles I've tried (PS1, PS2, Saturn, Mega Drive, Wii), minus the original Xbox which, for some reason, looks to be fine, maybe since it had the option to use a VGA cable over a VGA monitor they decided to go for a DC coupled output? Who knows. If this is true, then the Dreamcast might be ok as well.

The monitor I have in my SEGA Astro City is the original one, a Nanao MS8-29.

Probably your monitors are ok with AC coupled video signals, I'm pretty sure this is written somewhere over their owner manuals/service manuals, which is why you're not having issues.

 

[RealMFnG]

Unfortunately, it's not a simple issue of "degraged brightness".
The problem is that the brightness of the image varies based on its content because the monitor is expecting a fixed voltage across its RGB lines (which is how DC coupled video signals work) and instead the voltage fluctuates due to not having a reference voltage.

This is true for all the consoles I've tried (PS1, PS2, Saturn, Mega Drive, Wii), minus the original Xbox which, for some reason, looks to be fine, maybe since it had the option to use a VGA cable over a VGA monitor they decided to go for a DC coupled output? Who knows. If this is true, then the Dreamcast might be ok as well.

The monitor I have in my SEGA Astro City is the original one, a Nanao MS8-29.

Probably your monitors are ok with AC coupled video signals, I'm pretty sure this is written somewhere over their owner manuals/service manuals, which is why you're not having issues.

Thanks Don.

I just saw your post. Interestingly enough, after my last post, I immediately tried piping console SCART RGB right into my own Astro City MS8-29 monitor, and BAMMM! I see the problem you are mentioning. Looks like melted neapolitan ice cream. So must be just as you said, it is monitor dependant. Seems to work fine on a few monitors I have including the Wells Gardner K7000 however. And I do plan on using a K7000 for this project, so I think I should be fine with the solution I have.

 

[RealMFnG]

Hey @donluca, I am reading the Wells Garner K7000 manual and it says:

"INPUT SIGNALS
1v-5v peak to peak, (but says nothing about DC or AC voltage)
Both composite video and RGB analog: Both signal sources can be connected to the monitor at the same time. Monitor display can be switched from one to the other, at anytime at pixel or vertical frame rate."

So I am guessing that since it can accept composite video, and that composite video is AC coupled, that is the reason the K7000 has no problem with displaying RGBs from a console? Am I way off with my thinking here?