Console2JAMMA - can you amplify RGB ?

[Mr-Megalo]

Howdy peoples,

just a quick query to anyone who has hooked up a console to there JAMMA cabinets by tapping the RGB and converting the sync via LM1881 sync circuit I am wanting to amplify the RGB lines as they are a little dim on a couple of my monitors.

Edit - I've been told to add 220uF non polarised caps to the RGB lines, if i get polarised caps - anyone know which way the + & - go ?
ie is the + the input , & - the output or vice versa ?  

any infos on either boosting the signals would be greatly appreciated and welcomed very muchly  

T.I.A

[phreak97]

i dont know how a cap will boost the signal.. but the + end goes toward the console, and the - end toward the monitor.

[viletim]

Mr-Megalo,
If I design an RGB video amp can you build and test it on lots of different arcade monitors?

btw, a cap won't help anything - it'll make things worse.

[Mr-Megalo]

so I'm being fed the wrong info then  :blink:

so anyone know how I can amp the signal ?

viletim - I have 4 dual res Nanao monitors in my various cabs, the only real difference being the size of the screens themselves, but I usually test all my things on more than one cab/monitor, so yea I can certainly test on at least a couple of mnitors    

[viletim]

ok, here's what I've come up with...It's not been actually built and tested, only simulated. I'll probably be able to test it properly next week sometime.

I'm aiming for 100% compatibility with all arcade monitors (except those crazy ones that want inverted video). If you're building you own cables see http://members.optusnet.com.au/eviltim/gam...t/gamescart.htm for necsessary components.

notes/equivalents:
-IC3 (and associated parts - C7,C8,R17,R18) is optional, if your monitor will accept c-sync use it
-C1,C2,C3 are non-polar (aka bipolar) aluminium electrolytic calacitors. If you can't get em then use normal polarised electros with the positive lead facing the 75 ohm resistor.
-The aqua resistors are 1% metal film types, use normal 5% types if you like but if you do then the three amps won't be mached (some will amplify more than others, etc)
-If no BC548, use PN100, 2N3904, BC547, 2SC1815, or your favorite NPN general purpose transistor.
-If no BC558 use PN200, 2N3906, BC557, 2SA1015 or you favorite vegetable.

[viletim]

Here's the power supply. -V2 needs to be calibrated (due to different transistor characteristics, regulator error, resistor tolerance, etc) here's the method:

First connect the circuit to a console and a monitor to make sure it's all working properly. Then disconnect red, green and blue video from the input of the circuit (leave the c-video connected). Connect a volt meter between one of the video outputs and ground (while it's connected to the monitor). Adjust VR1 so the output offset voltage (what your meter is measureing) is just slightly above 0v (0.2v is ideal). Check that the other video outputs measure the same (they should if you use 1% resistors).

and that's it! er...any questions?

[Mr-Megalo]

viletim - any chance you could make up a sample.

now a slight change of plan, there will approx 12  - 18 different cabs that I would be able to test it on.

[viletim]

viletim - any chance you could make up a sample.

Possibly... If you don't mind paying for parts and postage I'll send
you my prototype (which has yet to be built) when I'm done playing
with it.

Check your email.

[Mr-Megalo]

okay cool, any idea what its going to set you back to make up the test unit ?

[viletim]

hmm...AU$15 should cover it

[Mr-Megalo]

many apologies for the delayed response, I have been just a little bit busy picking up/dropping off cabinets  :blink:

sure thing get it made up, ping me a PM and I'll PayPal you some dollah with my address details, theres at least 7 different machine in my home I can try it out on.

[Mr-Megalo]

sorry to bump an old thread

Tim - I've just today managed to aquire a 12v AC PSU (nicked it from an alarm system of all things  :lol:  )
i'm hoping to be able to get on with testing the unit this week with at least 5 monitors - all of them will be Nanao monitor but are from different cabs
theres

Aero City
Astro City 2
Capcom Impress
Namco CyberLead (this being the cab that gives me the dullest picture quality with consoles)
Pony Mk 4

[viletim!]

ok, sounds good.

btw. would you be able to try out a non-modfied playstation 2 with it? I'd be interested to know how it handles sync-on-green video (I think it should be ok).

[Mr-Megalo]

yea no problem - I only have non modified PS2's anyway (japanese & US)

[viletim!]

mark,
Have you got around to trying it out yet? I haven't heard from you in a while....

[Guest_Mr-Megalo]

e-mail sent to you viletim

to say I feel like a C U N tee is an understatement !  :unsure:  

[Mr-Megalo]

Viletim!
just sent you another e-mail, let me know if you get it and what you would like me to do next, this thing is excellent ! the picture quality is soooo much better its quite astonishing actually  

[Dave_K.]

Wow this is a good thread.  Bump for status from both viletim and Mr-Megalo.

[viletim!]

Thanks, I needed a bump. Incase anyone's interested I finaly got off my arse and revised (with an all new not-impossible power supply), tested, and published the thing. It now lives right here --->

[fiend41]

:lol: , fun  mr megalo   .    well i tried tried too for the 220uf,  it sucks !  nothing comes better.   i tried some other things   including the  n64 rgb booster from mmonkey,  and it doesnt change anything  :blink: ,   i figure a simple  75ohms in the composite sync would help to amplify sources?  sucks too .

these schemes are.. awesome,  i will never succeed i guess    real pictures would help a lot...    

[pro7]

me again... i forgot login.    i fact in past, i succeeded for some pcengine/megadrive mod on arcades.   but the old cabinet i had was better i figure,  it didnt need more amplification rgb (and wasnt on top of contrast... because i figure we all think it will consume them more   )

for the namco,  did you wire the pins jamma1 to jamma14 ?  ground video to ground ?   it's "frequent" to read it on astrocity/egret this problem of having bad picture with consoles.

[viletim!]

fiend41,
A few people have mentioned that to me... they'd like to build the circuit but don't believe they have the skills to accomplish it. I was thinking about designing a PCB and having a batch of them manufactured. But i'm not sure enough people would wan't one (unpopulated PCB) to make it worthwhile.

[pro7]

i guess.. but all is matter of final price  :rolleyes: ..  all console to jamma on DIY methods have the problem of contrast it seems...  second thought  i guess it would sell to some interested people

and about the "rgb amp" from pcengine plans ?!

"If you can get the parts and have the ability to assemble this amp, you won't regret it. For most monitors it's not necessary, though as mentioned above some won't sync without it. If you use an upscan convertor like the XRGB-2 you'll have a very acceptable image without the amp.

This amp (taken from PC Engine, a 1988 Japanese book) is quite small and will fit inside nearly every PC Engine system. You might have trouble with the GT and LT, but the rest are very spacious inside. As you can see it fits easily inside the CD ROM interface unit with plenty of room to spare. "


anyone tried it ?  i dont understand all the schematics and the only picture is imprecise :lol:  

[Guest]

:huh: no hope...no testers ?    

and about this schematic ?  anyone tested ?!

[Guest]

oops..

http://www.mameworld.net/pc2jamma/images/big/vamp.gif

[viletim!]

Guest,
This circuit is no good for most arcade monitors because it doesn't clamp (DC restore) the signal.  

[Guest]

ok... but so, can you figure hep what is really needed ?    science DIY needs our efforts    

[tsenzen]

RGB 21 pin / SCART Lead to 15khz JAMMA Monitor

so ive noticed theres a lot of buzz about amps and whatnot, but i have no idea where to start, heres my situation:

so this is what im trying to accomplish



i already have the jammaboard finger board, and was wondering if theres anything else missing?

What i already have/own:

Also have

ive read about the LN1881 circuit to seperate the sync? but im not sure if i will need it for this particular setup? I believe i can just wire the SCART/J21 Cable directly to the J-PAC? since its doing all the amps already?

and one more thing im using:

If you can see the board that the wii cable is hooked up to:  im wondering if the monitor adapter that ultimarc makes is basically an LN1881? im also considering just trying to run straigh RGB from a console straight through this similar board?

So i've mentioned all the components, and am wondering what is the BEST option to get the initial image (diagram) ive made above working with the best possible performance?

any info will help, thanks.

(I have over 5+ cabinets to try it with, incase there are any complications due to specific monitor types.)
Havent been on this forum for awhile, i really like what you've done to the place

please help!

[tsenzen]

everything is working btw..



i guess with this setup i might have to up the RGB gain pots 20-30% .. what solution could there be for this specific connector that ive accomplished to get the proper gain that a jammaboard would give out for example?

[Heffa]

ive read about the LN1881 circuit to seperate the sync? but im not sure if i will need it for this particular setup? I believe i can just wire the SCART/J21 Cable directly to the J-PAC? since its doing all the amps already?

and one more thing im using:

If you can see the board that the wii cable is hooked up to:  im wondering if the monitor adapter that ultimarc makes is basically an LN1881? im also considering just trying to run straigh RGB from a console straight through this similar board?

Ok, old thread and my first post here, but here we go anyway;

No, you don't need an LN1881 circuit to separate the sync if you are using this setup!
The small PCB connected to your Wii cable there is in fact a sync splitter (using LN1881) and a RGB signal amp 
I actually asked Andy (from Ultimarc) about this yesterday, and he confirmed that this was the case.

[RGB32E]

Wait a second, the NTSC Wii doesn't output RGB!  I checked out the action shot on the Ultimarc site and noticed that it looks like component video was being fed along with a sync to an arcade cab.  This would be the reason why the image looks so green (feeding component to RGB without conversion/decoding).



I wonder if their video amp would work with the RGB output from the TG16's expansion connector?
http://www.ultimarc.com/vidamp.html

[s8n]

hi team......Mr-Megalo + viletim

i too am still struggling with getting PS2 to Arcade Monitor i got Dreamcast to work properly ie Bright Colors Contrast and Brightness using a JPAC and Dreamcast Console Adapter from Ultimarc.  But Ultimarc PS2 one is quite problematic , alot of people have this problem too.

Ive spent alot of money and tried alot of ways to get PS2 working properly to no avail , my next attempt will be this Adpater , but first i need to get my Chassis Repaired by Jomac

http://www.happmart.com/Pro_Details.aspx?id=476&sid=89&px=6

viletim there is a gap in the market for a working PS2 to Arcade Monitor PCB , i recommend doing what Marilyn Manson did he saw a gap in the market exploited it and made a pile of money from it.

Ultimarc PS2 Adapter

[viletim]

My new SCART -> arcade monitor amp design is pretty much done, but I've just been sitting on it for a while. It would cost approx US$60 (including shipping), and I'd have to make at least 50 pieces to make it worthwile. Is there really adequate demand for it?

Features:

SCART input.
Audio output - passthrough.
Single pot contrast control (no need to turn three pots in unison).
Brightness (DC level) control.
Horizontal, Vertical, and Composite Sync output.
Runs from a regulated 12V DC power supply.

It should be suitable for all arcade monitors and all game consoles with RGB outputs. I will have organise some rigorous testing before I can change that to 'it is suitable'. Because both the contrast and brightness are adjustable it can also be used to directly feed the video signal to the neck board of a CRT television, should anyone want to do that in these days of plasma panels and blue rays.

Currently it only supports standard resolution video but I don't think that's much of a problem.

[s8n]

hiya viletim , i think what you are thinking of doing is superb.  To make more people interested in your design i recommend advertising it on

Build Your Own Arcade Controls Forum - http://forum.arcadecontrols.com/
Shoryuken.com Forum - http://forums.shoryuken.com/
Shmups Forum - http://shmups.system11.org .........i have read multiple people here have the dreaded Ultimarc PS2 Converter Adapter problem
Aussie Arcade Forum - http://www.aussiearcade.com.au/
Neo-Geo Forums - http://www.neo-geo.com/forums/index.php?
Arcade Otaku Forums - http://forum.arcadeotaku.com/index.php .............this is the new KillerCabs


btw the Gamecube has a different SCART GND pin i have found and it is not the same as PS2 and Dreamcast. You may want to tell people Gamecube will be incompatible unless they make a converter.

here is mine

[jepjepjep]

Hi viletim,

This sounds like a fantastic project.  Count me in for one if you decide to build them.

My new SCART -> arcade monitor amp design is pretty much done, but I've just been sitting on it for a while. It would cost approx US$60 (including shipping), and I'd have to make at least 50 pieces to make it worthwile. Is there really adequate demand for it?

Features:

SCART input.
Audio output - passthrough.
Single pot contrast control (no need to turn three pots in unison).
Brightness (DC level) control.
Horizontal, Vertical, and Composite Sync output.
Runs from a regulated 12V DC power supply.

It should be suitable for all arcade monitors and all game consoles with RGB outputs. I will have organise some rigorous testing before I can change that to 'it is suitable'. Because both the contrast and brightness are adjustable it can also be used to directly feed the video signal to the neck board of a CRT television, should anyone want to do that in these days of plasma panels and blue rays.

Currently it only supports standard resolution video but I don't think that's much of a problem.

[RobIvy64]

I have actually been building JAMMA Sega Genesis consoles for a few years. These systems are probably the easiest to convert to JAMMA. No sound or RGB amplifiers required!

Sound can be tapped from the headphone jack (must use a model 1), and RGB video can be sourced from the mainboard. RGB from the multi-out is too weak, so you have to find the signals before running through the voltage dividers.