John's Arcade Forum - Classic Arcade and Pinball Collecting and Restoring Discussion Forum - RETRO MAME - Nintendo Vs Forum

Hey guys, new to the group. 

I am building my first custom unisystem arcade.  I have built several successful jamma cabinets but I am a long time lover of SMB, excitebike, goonies, etc.  I have a VS unisystem board with SMB and Excitebike on it and I want to build a dual monitor cabinet with LCD panels to display and play the 2 games.

So I understand these these boards (obviously) can display 2 games at the same time, but they output inverted colors and unamplified audio.  So I need to do the following:

- Invert the colors for BOTH game video outputs AND convert that output from CGA to VGA so I can use LCD/LED flat panels.
- Amplify the audio

Is there an all in one adapter to do this?  I have found some adapters that will do one side of the board to allow one game to be converted, but not both.

Am I thinking this through correctly?  Any suggestions?

I have not had the best of luck getting those cheapy LCD adapters to sync on nintendo boards. I haven't tried the vs. but i assume its the same deal.

You will have to invert the video as you said. but not the sync. as the sync is proper negative sync.


https://www.mikesarcade.com/cgi-bin/store.pl?sku=VS2JAMMA This will invert the video and provide audio amplification but I don't believe it fixes the sync issue also it only allows you to play half the gameboard at a time, as you have noted.

If you were motivated enough you could build your own adapter, or beg someone to do it.
Technical of how that needs to be done:
 Need to break out both game outputs/inputs.
 Need to seperate the sync out to vsync/hsync and recombine to vsync with proper vblanking to allow sync of cheapy LCD adapter
 Dual audio amps.

Thanks iankellogg.

I am fairly tech savvy and pretty good with the iron, so i am confident in my building skills.  I have already purchased the edge connectors to make the harness off the unisystem board myself so I have that part covered.  If you could elaborate a bit on the comment:

"seperate the sync out to vsync/hsync and recombine to vsync with proper vblanking to allow sync of cheapy LCD adapter"

I am not an expert in video signals but I am pretty sure if you point me to a build example or to someone/someplace who can explain it in detail, I think I could do it myself.

I was eyeing up two of these boards to fix the inverted color issue, then feeding the output of those into a cga to vga adapters to feed the flat screens.  If you think this will not work, I will need to explore different options.

Thanks,
Jimmie

I can probably upload a schematic for both the inverter, audio amp and sync when i get home.

So a lot of games including nintendo games had a sync signal where the hsync pulses continue through the vblank. This allowed the monitors to maintain sync during vblank without needing a PLL circuit. The cheapy LCD converters do not like that and look for a solid long vblank pulse. So what you need to do is somehow break up the composite sync into its Hsync and Vsync components. and then recombine them in such a way that the Vblank doesn't have hsync pulses.

Awesome, thank you iankellogg....a schematic would be great.

I do know that whatever on-board converter they use on the jamma multi game boards seems to work very well.  I have no issues with any of my multi game cabinets and they all use LCD flat panels.  I assume you have read unfavorible reviews regarding these converters when used with unisystem boards?

Also, what if I were to use the Vision Pro monitors that accept a CGA 9 pin hookup to eliminate the need for the CGA->VGA converter?

if you use a proper monitor then it should in theory sync. but i have been burned in the past and not every monitor can sync to the weird vsync pulse.


The multi game boards don't have a converter at all, they generate the signals directly so they are doing it with proper vblanking

Here is a schematic that has video inversion as well as a simple 2W audio amp
(http://i.imgur.com/JyqziXT.png) (http://imgur.com/JyqziXT)

Thanks again.

I have found a couple of these inverter/amp boards for sale.  They are original nintendo AV-01 boards and I am hopeful they may work better than the aftermarket boards.  They were like $15 each.

(http://ggdb.com/img/ggdb/vol1/2192_1_fs_pb.jpg)

You wouldn't happen to know or where I could find the pin outs for this would you?

Thanks,

I have never seen that PCB before so I am not sure where you could find that information.

I have been looking up more information on the sync fix stuff but i still have to do some more research.

So I ended up going with the original nintendo vid converter/amp board (seen above) and a 19" Vision Pro LCD monitor that accepts a CGA input.  This way I do not need to purchase a cga -> VGA converter.

Next stop......assembly.

Edge connectors, wire, vid/amp board, and monitor should be here next week.  This will give me some time to get the cabinet assembly going.

I hope the converter works well. Please post an update when you get it all together