JAMMA supergun for Component TV with GreenAntz

[Zebidee]

I just finished making a JAMMA "supergun" because although I have a small collection of original arcade game PCBs, I had no way to test them. My last JAMMA cab was sold out of necessity many years ago when I sent my stuff overseas, and the PCBs have been in bubblewrap storage for about a decade.

Another reason to build the supergun is to test game PCBs on a component TV via GreenAntz RGB to YPbPr transcoder. I was also inspired to do this after reading Romshark's efforts to build his "Voyager" portable supergun in a small case.

This was my first full JAMMA AC+DC wiring job, a bit of learning involved. I improvised with stuff I had "lying around" mostly. There are certainly improvements to be made, but it works and demonstrates that you can use GreenAntz with an arcade cab and original PCBs.

I made the main AC power input into a $1 electrical junction box with a screw-down clear lid. The power cable is a simple PC-style so can be unplugged. There is a 10A line filter built into the female AC power socket. Active line then passes through a 5A fuse and simple SPST on/off switch before going to the DC PSU.

The TV and JAMMA are both plugged into a switched power strip, so I can turn both on at the same time. There is a separate switch for the JAMMA power, so I can reboot a game without having to turn the TV off.


   



Originally I powered the GreenAntz via a cheap USB phone charging cube. The phone charger cubes are usually fine when running GreenAntz with a PC/CRTEMU, but I was getting too much ground loop interference with the JAMMA. This phone charger interference made the video look bad, TV had trouble syncing. So I took the 5v directly from the DC PSU instead, and now the video looks perfect! To do this I made a special cable with female spade crimps on the PSU end, and 5mm exposed tinned wire at the GreenAntz end. Then I soldered a standard 5.08mm pitch 2-post screw terminal onto the GreenAntz (this was easy as the pads/holes are already on the PCB). I later marked the ground terminal black with a permanent marker to make sure I don't get the wires mixed up.

Finally, I put some 500R (500 ohm) pots in series on the RGB inputs to GreenAntz. This is to bring the higher voltage JAMMA RGB signals down to typical SDTV levels ~0.7vpp. I decided to use cermet multiturn pots for this as they are much better quality and easier to adjust than the standard cheap carbon film trimpots, which are very fiddly and break easily. The cermet pots also look better when installed onto some breadboard


   


Pots are needed because different PCBs output video at different levels. For most of my PCBs I could just leave the pots at 75 ohms, but for some, like Soul Edge, 150+ ohms worked better. For Wonder Boy in Monster Land, looked best with the pots to zero. There are no pots or resistors on the sync at all.

Some screenshots of PCBs working via GreenAntz:


   


Some more screenshots of GreenAntz working with arcade PCBs: http://forum.arcadecontrols.com/index.php/topic,164992.msg1741497.html#msg1741497


     

       

For more info about GreenAntz RGB to YPbPr transcoders: http://forum.arcadecontrols.com/index.php/topic,164245.0.html

[nitrogen_widget]

good info.
I have a few older PCB's non-jamma that need cabinets built and CRT TV is my only real option whether it's RGB modded, component or even svideo/composite.
I was aware of voltage levels from RGB board but didn't really look into it because i'm not there yet.
so thanks.

also, jelly of ghosts n goblins PCB.

[Zebidee]

good info.
I have a few older PCB's non-jamma that need cabinets built and CRT TV is my only real option whether it's RGB modded, component or even svideo/composite.
I was aware of voltage levels from RGB board but didn't really look into it because i'm not there yet.
so thanks.

also, jelly of ghosts n goblins PCB.

Thanks

Ghosts n Goblins is one of my favourite games! I also would like to make a small number or dedicated cabinets for my PCBs, starting with Moon Patrol, Wonder Boy, GnG and Galaga.

Arcade monitors are like hen's teeth in my part of the world, so improvising is essential!

I called this a "JAMMA" supergun, but obviously can also run non-JAMMA PCBs via converter looms (eg Wonderboy, WB in Monsterland, Ghosts n Goblins). Same principles apply.

You can use a similar arrangement for any TV/adaptor, whether it is SCART, component, svideo, composite or whatever - the RGB voltage levels will need to be attenuated before input. Most will also need a resistor on sync (500R to 1k), which you would also want for the SCART GreenAntz as it expects TV sync levels. You only difference is you don't need to attenuate sync for VGA GreenAntz, as it already expects higher level sync like that output by VGA (and arcade PCBs).

[bobbyb13]

Very soon I will have finisned all the cabinet work I have started so I can figure out all THIS other stuff that I am still fairly clueless about!

It really is fascinating (although still esoteric/archaic feeling still) to me!

[pakoman]

I love the control panel! 

It beats the one I made with a diapers box (it was the strongest cardboard I had at hand and only had a knife as a tool)