Arcade to RGB

[SavannahLion]

After reading a bit about the ups and downs of TVs, PC monitors and Arcade monitors. I decided to take a look at the monitor I have last night.

It's a Viewsonic 20G (it was too late at night and it was raining to get detailed model information. I should have it tonight). Unfortunately, there's no manual at Viewsonics website, but I did locate, what I hope, is the technical/service manual.

Anyhow, to my surprise, it uses five BNC connectors. RGBHV

Then I remembered somewhere on the forums, it was mentioned that the arcade feed is RGBS and compatible for a direct line to SCART.

M'kay.... They have SCART to VGA adapters and I have a VGA to RGB adapter in my hand. So can I jump from Arcade to RGBHV?

A little Googling later and I located a simple IC schematic ($4-$8 for parts and cables) for a SCART to VGA adapter. Two hours of pouring over the Arcade board schematic (I forgot to print one sheet up, DOH!) I found the pinouts to the video and they jived with what was linked to me earlier elsewhere on the forum.

In short, it looks like I can easily create an Arcade to RGB (or VGA even) adapter.

Yes, I'd rather use a real Arcade monitor, but there are too many constraints on me already on this project and obtaining a true Arcade monitor to use in the cab might take months or even a year or two, or God forbid, even longer. No way my GF is going to let me have a gutted cab taking up space for that long.

It really can't be this ridiculously easy, are there any pitfalls I'm missing?

The only two gotchas I can see so far is the voltage requirements don't line up quite right. If I have my information right, It's 1V from an arcade board and 5V from a PC video card... or do I have that backwards? I need to check my notes again. and the IC circuit requires power which is readily available from the VGA, but I don't see an obvious source from either the RGB monitor or Arcade board.

Edit: Technical changes

[modessitt]

 

[NickG]

you should have +5V somewhere on your arcade power supply; you can split it off from there.  Are you using a scan conversion circuit or else is your viewsonic capable of synchronizing with lower frequencies like 15-16kHz?   I would be interested in the $4-$8 dollar circuit if it doubles the scan for standard resolution boards.  That might change my dumpster diving behaviors . 

If your Viewsonic has an HD15, Dsub-15, DB-15 or whatever, it may be a more convenient place to connect your circuit and draw your IC power.  If it has DDC +5V on pin 9...   

[SavannahLion]

Are you using a scan conversion circuit or else is your viewsonic capable of synchronizing with lower frequencies like 15-16kHz?

There's the gotcha.

The monitor is a Viewsonic 2082G-2 (20G) 20" monitor. It sports a 5 BNC connector which, according the manual, supports RGBHV, RGsB (sync on green) and RGBs (composite sync, what the arcade board puts out). Because it supports RGBs and not just RGBHV as I initially thought, there would be no need to build the circuit I was talking about for this particular monitor.

Which is all besides the point. I couldn't tell just by looking at the monitor, but according to the service manual I located, the monitor does not support a 15kHz signal.

I didn't bother chasing after the voltage requirements after that.

---daisies---.

Right now, I'm just looking around cursing U.S. standards and reading up on scan converters and trying to figure out why most scan converters are so damn expensive.

[segasonicfan]

Yeah....this has been covered in depth a lot and I hate to see people meet this brick wall over and over again.  99.9% of all VGA monitors out there won't support 15khz and thus cannot play arcade games.  The best way around this is to invest in an X-RGB scan converter.  They upscan the 15khz signal to something VGA monitors can use.  They are regarded as the finest product for this by far and usually run around $200-$250.  Keep in mind that the image will still not be perfect though as arcade games are designed for interlaced monitors which VGA monitors are not.

If you want my advice I suggest you invest in a true RGB monitor which will cost less than an X-RGB and look better.  Sony PVM's are the cheapest available and you can score them cheap off ebay (PVM-2030 and PVM-2530 being the best for the price).  They're great for standard home use if you don't want an open-frame arcade monitor but they will not give you as nice of a picture as a Wells or Nanao.  Still far beyond anything else on the market though.

-Segasonicfan