TV RGB(SCART, etc) to JAMMA RGB+CSYNC signal converter

[Neovanglist]

Hi there guys,

A while back people were talking about using the LM1881N chip to do the sync signal separation needed to get game console video output to work correctly in an arcade machine.

I commented (to what avail I'm not sure) that this was not enough in most cases as the video output of a game console is often AC-coupled. (The baseline of the RGB signal is not 0v)

So you will get proper sync, but you will not get proper RGB levels and it can (will) look tinted/washed out.

An example of this is the Playstation 2, where it will "work" but you will get a tinted image with nasty color saturation issues.

This can be "compensated" for by cranking up and playing with the RGB pots on the monitor chassis, however this is not a real solution to the problem, and often times the remote board pots are not even enough... and you have to adjust the gain pots on the chassis itself to get decent looking levels.

The downside to this is that it doesn't really "fix" the problem and it also means when you put anything else into the cab your color levels will be really messed up.

To solve the problem, I've designed a PCB that does both the sync separation and "DC restoration" on all 3 color channels.

It has a 6 pin input header which takes Red, Green, Blue, Composite Video, Ground, and +5v. (All can be sourced from a SCART connector)

The output is another 6 pin header which outputs Red, Green, Blue, Ground, CSync, and VSync.

The color signals are all "restored" to a 0v baseline so they will be in the exact signal format that the arcade CRT expects.

It performs this level calibration automatically, so you do not need to turn any pots to achieve the correct levels. The whole process is adaptive and automatic based on the input signals.

Below is a picture of the PCB layout:
http://www.neovanglist.net/~Neovanglist/board.png

I have commissioned the production of two prototype PCBs this week, which should arrive by the end of next week. (Or soon thereafter)

Assuming everything works as expected (the same way my early prototypes here do) I will be offering them to the community at a very low price... it depends on how many people are interested, but it'll be between $30 and $50 a board. ($30 if we can get > 20 orders, $40-$50 if we only end up with a couple)

The boards are all commercial quality finished, with soldermask, silkscreen labeling, etc. (I have contracted a PCB fab plant in asia to do the board production)

I have selected the highest quality components possible for the board, including 1% tolerance for all resistor components for the best possible signal quality and minimal to no interference. (This is about as good as it gets)

I am also investigating a version that will do the same function from component video sources... but this is much more complex as it requires YCbCr colorspace conversion to RGB as well. (Which needs another chip that is much harder to integrate)

Also, the board is solderless using the following connectors for input/output:

http://www.neovanglist.net/~Neovanglist/1725698.jpg

Let me know if you are interested!

(Btw, I crossposted this on killercabs to get more people interested.. (and get us lower prices) but you should reply here instead of there because I'm giving everyone from we-play-games a $5 discount over the kc offer!)

[Mr-Megalo]

registering my interest

btw - how will this unit be powered ?

also, I am sending you a PM about something similar which was built a couple of years ago by one of the members of gamesx forum

[Neovanglist]

It uses a normal +5v, which can be sourced easily in a cab... and can even be sourced directly from the SCART connector!

This way you can either power it via your cab or power it via the SCART line.

[Mr-Megalo]

runs from the 5v on the scart, awesome !
as said, registering my interest for one please

[La4s]

I like discounts. I am down for 1.

[joeblade]

Im interested too Neo & thanks for all the hard work so far m8!! :cool:

[neokoen]

I'd be intersted in one of these too.

Are you by any chance planning a version with JAMMA edge and SCART connector instead of screw terminals and perhaps pin headers for the button mapping ?

[vib_ribbon]

it sounds very interesting... but can either yourself or someone else explain to a dunce like me what the possibilities are?? what i mean is, in a practical sense, what would i be able to use this for?

[Mr-Megalo]

vib, its for using consoles on an arcade monitor
normally when using a console 2 JAMMA setup using an LM1881 sync stripper circuit the RGB levels are quite low, so you either need to use an RGB amp from ultimarc or yank up the levels using pots on the remote board/chassis.

Mr Vanglists device removes the need to do either

[vib_ribbon]

from the RGB out, you would have to make a build a jamma adapter of sorts i presume and with the audio going directly from the source/ console to the same adapter as well. controls would come in the form of a hacked joypad? am i on the right track?

[Mr-Megalo]

correct on all counts

[vib_ribbon]

i wonder what would be the dimensions of the final product?

and would someone be able to build me a DC to JAMMA adapter from it? :blush:

[neokoen]

from the RGB out, you would have to make a build a jamma adapter of sorts i presume and with the audio going directly from the source/ console to the same adapter as well. controls would come in the form of a hacked joypad? am i on the right track?

And that is why I think it would be interesting to design the PCB with a JAMMA edge from the start. However then you also need to be able to draw the button lines from the PCB (e.g. through pin headers). You then would have to make a cable that plugs in the pinheaders and is wired to your hacked pads.

Problem is sound, if it also goes through the JAMMA edge you need either a sound amp incorporated on the board or better yet, jumpers and pin headers so you can add your own :mellow:

Since one can get a SCART cable for almost all consoles a connector of that type on the PCB would make it very accessible to everyone.

[Mr-Megalo]

I plan to use mine in a PS2>JAMMA format.

btw Vib, remember you had issues with the DC Super MGCD thingy, the problem has been solved - you DEFINETLY need an adaptor, I got thechops working for him.

[vib_ribbon]

well, i guess the idea from neovanglist is to make it as open ended as possible?! i don't know, that's why i asked. if there are other applications for the pcb other than making console to jamma adapters, this would be ideal...?

[vib_ribbon]

I plan to use mine in a PS2>JAMMA format.

btw Vib, remember you had issues with the DC Super MGCD thingy, the problem has been solved - you DEFINETLY need an adaptor, I got thechops working for him.

the super that i had from jaysee had 2 probs, 1 which i know now was the fault of my own cab (ie, monitor is flipped and the super had no flip dipswitch). the other was the inability to coin up. is the latter what you're referring to?

[neokoen]

well, i guess the idea from neovanglist is to make it as open ended as possible?! i don't know, that's why i asked. if there are other applications for the pcb other than making console to jamma adapters, this would be ideal...?

Well if you have a VCR with a tuner (or digibox) with SCART-RGB out you could watch TV on your cab :laugh:

[Neovanglist]

Hi there guys,

Well this is another component of a bigger final project I have in the pipes.

Remember the open design for a stereo +12v arcade cabinet sound amp I posted a while back?

Well... eventually that will be combined with this to create a video/sound amp combo board.

The only reason that I didn't give this a JAMMA edge connector is that you will still need to sort out audio and input, plus I needed to test this component by itself first to make sure it works correctly.

The audio amp has already had prototypes built and working, so it's good to go.

The idea after this is to make an input converter board from Playstation/Playstation2 pad format to JAMMA using a small microcontroller.

The point of doing these as separate modules is that they will be combinable later on to create a variety of homebrew arcade cabinet adapters

Of course to do this I need to be able to actually prototype and buy parts in bulk for each individual component of the adapter (video, sound, input) and I'm selling some of the standalone boards that I'm making in order to help cover my expenses.

(This project as a whole with audio+video has already set me back back 300 quid personally, plus all the time involved.)

As far as dreamcast goes, I have not done reverse engineering with regards to it's controller interface so I'm not really sure how complex that would be.

Truth be told, I'm actually having some issues sourcing the ISL4089IBZ chip which I use for the DC restoration now... my boards and components arrive monday and I'll assemble my fab prototypes during the week and let folks know how it goes.

If I still can't source the part I'm going to go straight to a more updated design which will allow for SCART or Component video in, as well as do YCbCr to RGB colorspace conversion and have 480p->31k support.

If people would rather hold off until the final packages are ready then that is fine... but by selling these I have more money to invest quickly in prototyping new designs to finish the project :)

The final design will work something like:

JAMMA Edge board with SCART/Component Video in, Audio From SCART or RCA audio switch, JAMMA edge to source power and output audio(mono)/video, 4pin stereo out connector, then a ribbon connector to connect an input translation daughter board. (Swapple between PSX/DC/etc)

My current pledge to everyone is that for each component once one round of prototype sales has been done and I've recouped at least some of my own costs then I will release the drawing CAD files and part lists in full to the community. (Much like I did with CGAmp)

I hope this clears things up... and I'll keep everyone up to date.

Edit:

Here's the schematic and board layout for CGAmp from my old post on KC... it's a bit outdated but it's a known working design:

http://www.neovanglist.net/~Neovanglist/CGAmp_Board.pdf

http://www.neovanglist.net/~Neovanglist/CGAmp_Schematic.pdf

[Mr-Megalo]

interested in the amp and the component version too, also interested in the PS2 controller interface

[vib_ribbon]

everyone's so early today...! i'm jetlagged and have come down with the flu, what's your excuse? :wub:

thanks for sharing your ideas with us neovanglist, it sounds like a very ambitious project and i wish you all the best with it. many aspects of this project sounds more horrendous than bringing in cabs i tell ya...!

with me personally, i'll only be interested in the final product. if you can also work with some product designers on a housing unit for the components that would really finish it off nicely. :wub: good luck, dude!

[Mr-Megalo]

bump for a progress report / updates
anyone seen or heard anything from NeoVanglist recently ?

[thchardcore]

Hi, new to these boards, but this caught my eye. I would definitely be down for one of these as well.

[vib_ribbon]

Hi, new to these boards, but this caught my eye. I would definitely be down for one of these as well.

welcome to the forum, dude. :esprade-flying::character-p3::character-p2:

[Mr-Megalo]

/tips hat

welcome thchardcore

mr vanglist hasn't been here in awhile, I'd like an update to this myself

[alien_mame]

Neo has recently got back online - give him a day or three to catch up with the inevitable backlog.

Cheers

[Blue Max]

Hi all, has there been any updates or progress on this?

[Mr-Megalo]

nope, infact from looking at his profile, he hasn't been here in almost a year

[tsenzen]

im also working on a similar design (minus the chips).. buy making my own boardless circuits. I was also stumped by the sound amplification, along with the video amplification.

if someone were to make a laments version of what components i need to make, can you list the ingredients of what i might need?

Im getting tired of breaking old 2.1 computer speakers for amplification, and have still yet to figure out how to amplify my RGB vid signals without some form of physical circuit?

any help will be gratefully appreciated thanks.

[Mr-Megalo]

Andy @ Ultimarc used to sell a small video amp, he may still do so

[tsenzen]

thanks for the reply Megalo,

I cant seem to find anything on the ultimarc site regarding the RGB amps..

however ive ran across using supposed 75ohm, and 220uf capacitors between the lines.. im not really sure what each components job is for, but i will try this further down the line, to see if it aids in the amplification.

thanks again.

[Mr-Megalo]

I used 75ohm resistors to reduce RGB levels on a previous supergun I had and some scart leads use 220uf caps to slightly boost the signals (Mainly PS2 scart leads that i've seent his with though)

[vib_ribbon]

I'm sure my PS2 lead has these capacitors in it too.

[tsenzen]

I used 75ohm resistors to reduce RGB levels on a previous supergun I had and some scart leads use 220uf caps to slightly boost the signals (Mainly PS2 scart leads that i've seent his with though)

so if this is the case, what components would i need to actually "boost" the signal?

Ive also read that the 220uf's restrict, rather than boost.. so im assuming the 75 ohms.. are the boosters? not the restrictors?

very inconsistent with all the info i can find so far, was wondering if we can figure this one out. I mean, the adapters ive made seem to be fine with no added components.. however require the adjustment of RGB gain pots via the cabinet.. and this can get cumbersome when dealing in and out with jamma boards..

ideally i would love my RGB adapter to amp the same video gain as a typical jamma board.

i know the answer is simple, the components are all scattered, just need to figure out the correct ingredients.

thanx for all the help so far.

[vib_ribbon]

i've just checked. i was wrong, my ps2 cable only has 1 resistor in it... it is my super famicom cable that has the 3 capacitors.

if you need photos, lemme know. i forgotten how to read the stripes on resistors. this one is tiny.

[Mr-Megalo]

so if this is the case, what components would i need to actually "boost" the signal?

Ive also read that the 220uf's restrict, rather than boost.. so im assuming the 75 ohms.. are the boosters? not the restrictors?

very inconsistent with all the info i can find so far, was wondering if we can figure this one out. I mean, the adapters ive made seem to be fine with no added components.. however require the adjustment of RGB gain pots via the cabinet.. and this can get cumbersome when dealing in and out with jamma boards..

ideally i would love my RGB adapter to amp the same video gain as a typical jamma board.

i know the answer is simple, the components are all scattered, just need to figure out the correct ingredients.

thanx for all the help so far.

the statement i've highlighted in BOLD is inevitable i'm afraid, RGB levels on consoles are usually lower than from a JAMMA PCB so the changing of RGB levels is exactly what I had to do myself.

the only cure I found to get similar RGB levels as of that from a JAMMA PCB was the seperate Video amp that Ultimarc used to make (he hasn't listed them on his site for a long time !) but he may still have some old stock kicking around or have the schematics for it.

the J-Pac has a built in video amp doesn't it ? just a thought but say for example a PS2 (with or without sync stripped using LM1881 - not sure if J-Pac does this or not) going into J-Pac, which then amplifys the picture using its onboard video amp ? would need to be wired to a VGA socket though.

you and vib are in the exact same position, because Vib is going to notice these issues using his downscanner and his laptop on his Egret 2, the picture quality although stable will look alittle washed out and the colours WILL look dull before RGB contrast and brightness tweaking

[cools]

I know the guy that designed the video amp that Ultimarc used to make.

I'll ask if he's still got the schematics.

[tsenzen]

I know the guy that designed the video amp that Ultimarc used to make.

I'll ask if he's still got the schematics.

that would be great, turns out after contacting, andy doesnt have any old amps left.

a schematic for this mod would be perfect.

thnx for all the help

[tsenzen]

wondering if you've got any updates?

the closest thing i found was the similar amp used in the NES RGB mod:
http://i16.photobucket.com/albums/b14/moosmann/electronic/NEW-RPG-Amplifier.jpg

wondering if theres anyone that can translate the bottom portion of the diagram, (more laments for me)

[Mr-Megalo]

afraid I can't help with the schems.
might be worth joining up to www.gamesx.com 's forum (or at least having a nosey through the RGB video forum)
http://nfggames.com/forum2/

couple of members helped me in the past

[Mr-Megalo]

tzenzen, I have found something that a chap called "viletim" from gamesx forum made up for a me a few years ago that I had forgotten all about till recently

i'll post a pic up as soon as I get a minute

[tsenzen]

sweet, cant wait~

anything will be quite helpful :)

[vib_ribbon]

thanks to mr meg for the kind donations.

lemme know what information you need tsenzen and i'll see if i can help?

http://farm3.static.flickr.com/2528/3861624637_2b3b535e36.jpg

large version:
http://farm3.static.flickr.com/2528/3861624637_2b3b535e36_b.jpg

largest version:
http://farm3.static.flickr.com/2528/3861624637_bca3197ba4_o.jpg

[tsenzen]

Thnx for providing the picture

If i can get a diagram for that amp , pictured in the bottom, that would be perfect.

[vib_ribbon]

does this help??

http://farm3.static.flickr.com/2459/3862939722_a3b39ff15f.jpg

large:
http://farm3.static.flickr.com/2459/3862939722_a3b39ff15f_b.jpg

largest
http://farm3.static.flickr.com/2459/3862939722_6317ac0a4d_o.jpg

[tsenzen]

Thnx again, ill give it a shot when i get sone time this week, im still not too sure the details of the ohms & K for the resistors/capacitors?

[vib_ribbon]

i'll take a picture of the markings for you, but i've forgotten how to read the bands across resistors since i did my electronics at A level 17 yrs ago.

[tsenzen]

heres some more diagrams i found, i think i might have the proper information to work on an amp thanks everyone :)

this one is for a genesis(svideo)booster
http://www-unix.ecs.umass.edu/~dhowland/mod/images/schematic.png

http://www-unix.ecs.umass.edu/~dhowland/mod/images/2N3904.jpg

and lastly andy's diagram schematic from vib_ribbons photo: (however this is the one pictured from the top, not the RGB amp pictured on the bottom?):
http://farm3.static.flickr.com/2608/3868559896_37b647bf0d_o.jpg

[tsenzen]

so i just found out from another diagram, that there is no RGB amplification on the top circuit board from ultimarc..

however judging from this other diagram, using standard 220uf 10v capacitors

http://farm3.static.flickr.com/2521/3870713400_b24e365eeb_o.jpg

but it seems to be used in the wrong direction? these capacitors are the general ones found inside European SCART connectors. However its not found in J21 RGB cables.. i think the 10v doesnt make any difference on the cabinet from what ive experienced so far.

With this said, I will try Higher Voltage Capacitors without any resistors to see if the image brightness or gain changes if not at all?

[Mr-Megalo]

Hi tsenzen,

you are correct the top PCB shown is an ultimarc PS2> arcade video cable (i got one without the VGA connector for the J-Pac) - thats why it has the LM1881 circuit integrated into it
the bottom one is the ultimarc RGB amp - which is the one I believe Vib is using now on his setup

[tsenzen]

so i figured out i need a transistor, but not sure of what type that would be ideal for running consoles to a general amplifier that will hook up to an arcade cabinet.

it seems that every amp diagram i see, has been ideally conditioned for its console counterpart. Most transistors seem too low? but im not sure where i should start in terms of watt count for the transistor and or NPN versus PNP.

cant seem to figure out which ones been used in ultimarcs rgb amp//

[vib_ribbon]

is there anything else i can do to help you figure this out? can you put a circle around the part you need to closer examine in my pictures? just lemme know.

[tsenzen]

the ultimarc amp seems to use a specialized op-amp so i really dont know where to begin or attempt to find that.