RGB monitor question

GaijinPunch · Post by **GaijinPunch** » Fri Dec 02, 2005 1:02 am

This RGB Monitor on YJ looks pretty good. He's made the input 21-pin compatible, but he says that the signal on a consumer game machine is slightly different. AFAIK, most Japanese game machines have 21-pin RGB signals. Why do they not work on these monitors, yet my Sigma super gun works fine on both?

SAM · Post by **SAM** » Fri Dec 02, 2005 5:30 am

That's preatty much what I got at home.

Missing the shielding box through...

Some cosole (e.g. PS1/PS2) got composit vedio outputing at the composit sync pin for RGB. A RGB could accept this singal but not an Acrade monitor.

The solution is simple, you just build a simple circult using the LM188N chip (an IC chip) to seperate the composit sync singal from the composit vedio, before feeding it into Acrade monitor.

The circult is so simple that it could fit into the 21 pin RGB plug of the console. A single LM1881N chips would only cost you a few bugs.

I have successfully connecting my PSOne and PS2 to an Acrade monitor using this method. I got some extra LM1881N chips left, I can send some to you if you wish.

elvis · Post by **elvis** » Fri Dec 02, 2005 8:18 am

http://www.mameworld.net/pc2jamma/

All you need to know about LM1881N circuits, and console->RGB conversions is on that site. It's a brilliant resource.

There is simply no better way to play console games than on true 15KHz RGB monitors. It blows away the image quality of any other method I've ever seen, excepting only the native 31KHz VGA output of the Dreamcast of course (the ONLY way to play your DC).

Good news for modern console fans is that most (if not all) the new consoles will be supporting VGA out, as well as digital via HDMI or DVI.

GaijinPunch · Post by **GaijinPunch** » Sat Dec 03, 2005 8:55 pm

Thanks for the info guys. At the moment, I have a pretty solid RGB monitor (Sony PGM) but am curious about how it works, and the monitor. I've been told the Arcade monitors are even better than the PVM's which aren't so hot for TATE'ing.

SAM · Post by **SAM** » Sat Dec 03, 2005 11:27 pm

GaijinPunch wrote:Thanks for the info guys. At the moment, I have a pretty solid RGB monitor (Sony PGM) but am curious about how it works, and the monitor. I've been told the Arcade monitors are even better than the PVM's which aren't so hot for TATE'ing.

Well, acrade monitor is made for TATE'ing.

They are CRT and they are normally cheaper and bigger.

This is the hotist monitor I ever found

http://www.riverservice.co.jp/j/monitor/index.html

42" inch CRT 4:3 monitor support VGA i.e. 31kHz.

You could connect you PC to it, use it for viewing viewing DVDs in progressive scan, play games that support progressice scan or VGA.

And since it is 4:3, it got a screen area even larger to most Plasma. It is CRT so it would brighter than Plasma and is not likely to encounter the burn in screen problem as Plasma would.

The cost is 293,000 yen, about US$2,460 at current exchange rate. Costs less than a Plasma. The only problem is it is too big to fit into your hourse...

elvis · Post by **elvis** » Sun Dec 04, 2005 12:25 am

GaijinPunch wrote:Thanks for the info guys. At the moment, I have a pretty solid RGB monitor (Sony PGM) but am curious about how it works, and the monitor. I've been told the Arcade monitors are even better than the PVM's which aren't so hot for TATE'ing.

At a tube level, and RGB monitor and a TV are identical (technology wise - different brands obviously give different picture qualities). The only difference is the chassis, or the electronics that drive the pictures.

Technically speaking, most modern TVs can be easily hacked into RGB monitors if you know what you are doing. Although I very hesitantly suggest going down this path, as if you DON'T know what you are doing you risk destroying your TV, or worse: electrocuting yourself.

If you want to know exactly how an RGB monitor works, read up this guide:
http://easymamecab.mameworld.net/html/monitor1.htm

That is the single most comprehensive guide I've ever read on how modeline information gets converted to picture information. From that you will also understand progressive versus interlaced scanning, blanking signals, and how teletext is "hidden" in broadcast signals in unseen lines. Very clever stuff.

Any TV with real RGB input (ie: SCART, CGA or VGA) will give you the same quality as a true RGB monitor. With some easy hacking you can plug game boards direct into RGB-in TVs, you can use tools like PowerStrip and AdvanceMAME to force PCs to output 15KHz modes direct to the TV (without a TV encoder making the picture look blurry and crap) or just use SCART from a console for superb image quality.

Arcatech · Post by **Arcatech** » Sun Dec 04, 2005 12:52 am

It's too bad RGB isn't readily available in the US. I would go for it otherwise.

elvis · Post by **elvis** » Sun Dec 04, 2005 1:33 am

AFXisatwin wrote:It's too bad RGB isn't readily available in the US. I would go for it otherwise.

It frustrates me that TV manufacturers have this mentality that only 1% of users actually appreciate RGB, and therefor they'd rather save $5 on manufacturing costs by not adding it to their units.

With home theatre becoming more and more popular, it seems RGB is coming back. However that doesn't help most of us, as it's all going into digital TFT and Plasma panels, instead of cheaper CRTs where it's actually more useful (seeing as CRTs are actually analogue RGB devices, and Plasmas and TFTs are digital).

GaijinPunch · Post by **GaijinPunch** » Sun Dec 04, 2005 5:48 am

Thanks for the link elvis. Will give me something to do if I get some downtime at work. You are the king!

GaijinPunch · Post by **GaijinPunch** » Mon Dec 05, 2005 6:26 am

One question. I've read some of the pc2jamma page, and all the hacks are for a jamma cabinet. What if you're just wanting to use the monitor? If that's the case, is it only the compositive video sync and the composite video that have to be seperated?

elvis · Post by **elvis** » Mon Dec 05, 2005 8:53 am

JAMMA is merely a standard for which most arcade cabinets conform. It includes a standard 4-microswitch joystick, 3 fire buttons, coin and start per player, as well as stereo sound and RGB+Sync for video.

If you are using an RGB monitor just follow the video parts. The guide will be identical. And yes you are right, you just need the RGB values, and the LM1881N sync seperator circuit output to plug directly into your monitor. Some monitors can take an unseparated signal and fish their own sync signal from it, but often the signal is weak. It's better to use the LM1881N hack all the time, as it suits the vast majority of monitors, and only requires a $2 part and some solder.

I have a JAMMA cabinet that I'm going to wire up for PSX and PS2 play. I'll be doing my own dual shock hack, and outputting the sound to brand new speakers (as the speakers in the cabinet I bought are mono, and almost dead). So I won't be wiring it all up to a JAMMA fingerboard, but instead wiring it directly into the RGB monitor.

Then I'll do the same with my current MAME box (simply twisting H and V syncs together which is the cheaters way, as well as using a video amp to up the signal voltages) so that will be on 15KHz output too (with a switch to choose PSX or MAME). Then my current 21" VGA cabinet will be converted from MAME to Dreamcast, and I'll be in heaven.

GaijinPunch · Post by **GaijinPunch** » Mon Dec 05, 2005 8:09 pm

Nice cab! I will most likely never have a cab unless I live in a place with a garage, or get a new wife. Neither will happen soon, very likely. I have a question about this LM1881N circuit. Where exactly do you put it. I take it it's connected to both ends of the cable (from the console, to the monitor).

My current project is playing MAME on my RGB monitor. Matt is currently making me a cable. I'm sure I could do it now that I see the right pinout on that page, but to be honest, I'm not quite sure what the pinout of my little adaptor is (also made by Matt). My one concern is that if I ever move from Hawaii, I will probably not take this gigantic ass monitor.

Post pics of your PS2 cab when it's done. Kind of jealous. I really want a cab.

elvis · Post by **elvis** » Tue Dec 06, 2005 2:08 am

A standard SCART cable sends composite video (ie: Luma, Chroma and sync all in one) on pin 20. So you take the output of pin 20, and use the LM1881N circuit to strip just the sync signal out, and aplify it with a 5V source. The output is then a nice clean and amplified H+V sync signal which you can feed directly into most RGB monitors on their sync input.

If you aren't plugging into a JAMMA biscuit, you may need to find a 5V source from somewhere.

Instead of hacking my Playstation's SCART cable directly, I'm just building a SCART input -> 15KHz JAMMA converter, and then I can plug in any console I want after that.

GaijinPunch · Post by **GaijinPunch** » Tue Dec 06, 2005 3:48 am

That's probably the way to go then. I assume it would work with any Japanese 21-pin RGB cable?

elvis · Post by **elvis** » Tue Dec 06, 2005 4:02 am

GaijinPunch wrote:That's probably the way to go then. I assume it would work with any Japanese 21-pin RGB cable?

The only difference is that Japanese SCART cables have their pins wired differently to US/Euro SCART cables. Double-check your pin values first.

All the RGB and Sync info will be there on Japanese cables, just on different pins.

Generally speaking I've just followed the pc2jamma website pinouts to the letter, and never had any dramas, but I'm in Australia, and all our systems are pretty much PAL Euro boxes.

GaijinPunch · Post by **GaijinPunch** » Tue Dec 06, 2005 7:27 am

Yeah, I'm in teh US, and they all suck.

I new about different pinouts (stupid, no? I mean... why?) which is why they say that Euro is SCART, and Japan is just 21-pin RGB. At least I heard that one place, but what the fuck do I know? I'm a yank.