Question about home built Jamma rig

[CthulhuLuke]

K, so I've been getting very very curious about making my own Jamma Rig so I can buy some PCBs off of ebay, and play em on my tv, and possibly on my mame cabinet when I get a TV for that.  Here's the Jamma Rig I was looking at:
http://cps2shock.retrogames.com/jamma/jamma-m.html
 So I have a few questions about this setup.  
A: my cabinet came with a Rampart PSU, and it seems to still be working fine, so I was wondering if I could just use that as the PSU in this Jamma Rig, and it'd be compatible with all the PCBs I buy off of ebay.  *Life Force, me want bad*
B: for the video out from the pcb board, he talks about having it as an SCART out, but I believe that's only on European televisions, so I was wondering if it'd be possible to wire up either an s-video output from the board, or a straight composite output *the yellow one*
I was also wondering how safe this thing would really be?  I mean yeah it's got the fuses to protect the power supply, but couldn't the power supply catch something on fire.  Also, would I have to shield this thing's insides ilke a mofo, to prevent interference between the pcb and the PSU?
Has anyone made one of these before in BYOAC?  I know people have made homemade MVS setups, but I haven't seen a pure Jamma rig here I don't think.
  -Thanks
     -CthulhuLuke

[kspiff]

A: I don't see why you wouldn't be able to use the Rampart PSU provided it has all the standard voltages that a JAMMA harness requires.. the only issues I've read between different boards seems to be when the board requires the same voltage but a different amp rating (don't shoot me if I'm stating this incorrectly).. most of these boards seem to be non-JAMMA and require an edge connector adapter anyways, though, so..
B: I'd have to look at how they were doing this for their SuperGuns, but I've seen a lot of different rigs with non-RGB video/audio-out solutions (most of these weren't the joystick-and-rig-in-one type, though -- separate project box and joysticks).. you should look around for a project how-to that cites how to rig for s-video -- no, though, I don't recall a specific one (my JAMMA plans include an arcade monitor in a full cab so I didn't do any research).. also don't recall if they were using scan converters or not (but I would have to assume they didn't for space reasons.. unless that's why all those non-RGB ones were in separate project casings).

As for the PSU question, I would assume that shielding isn't a problem (the PCBs in a real cabinet are *almost* as close to the PSU as they are in a test rig [@6-8"]).. also -- as long as the PSU has a load on it -- I don't see why it would burn out.. and I've never heard of a properly connected PSU being a fire hazard, but someone may want to correct me on that shortly <winkwink>..

Just found this by typing "Supergun" and "S-video" into Google :

Quoted:
"Another popular option is to use a RGB->composite/s-video converter. This is a device that converts the 15.75 KHz sync and analog RGB video into either s-vhs or composite video suitable for display on a standard television. There is some signal degradation involved in the conversion process, so the image will not look as clean as a pure RGB/sync signal. James Rowan makes a very high quality converter that will give the best looking picture of any I've seen.

http://www.jrok.com/hardware/RGB.html"

Yes, the link actually works, too!

[CthulhuLuke]

Cool, thanks for the info.  So if I use that convertor, all I gotta do is run out the video outputs from the jamma pins and place that in the back of the jamma rig, so I can just plug it directly into my tv.  Sounds like it'll be an awesome project.  Yeah, I'm not too worried about power supply conversion problems then if the non-jamma games need em, since I think I'm just gonna look for old school deals on classics that it'd be cool to have the real pcb of, and I bet S-video from an arcade pcb to my 20" sony wega would look freaking awesome.
  I wonder if it'd be possible to make your own adapters for a psx input to the jamma rig, so I could just plug my other joysticks into the jamma rig, anyone have any input on this idea?
  -CthulhuLuke

[kspiff]

Actually, there are some out there who have commented on the subject of hooking a JAMMA rig into a TV.. negatively.. but I guess it's a matter of taste and what boards you get.. he also mentions the PSU issue I had brought up here.. can you adjust the +5 on your PSU (this seems to be the main caveat between standardized JAMMA boards)?  Hell, he even hacked up Neo Geo, Saturn, and PSX pads (though there must be an easier way with more explanation).(http://www.alamone.com/jamma.html)

Will edit post if I find a page that cites how to hack PSX pads into JAMMA rig.

EDIT: as I expected -- based on the number of pins on the controller -- the PSX pads will likely be a pain to hack straight in with no convertors.. this website explains a bit about them (http://www.epanorama.net/documents/joystick/tvgames.html).  As you can see, they would need some kind of device to translate the gamepad signals into something useable by/compatible with JAMMA.

[CthulhuLuke]

Hmmm.. yeah I've been looking a lot at that guy who did the jamma box, and I think you're right, it'd be wayyyy too hard to do a psx input hack.  The only way I could think of is if there's someway to make my own data splicer, so like I could take a USB convertor or something, and take out the USB part, and put in a DB-15 or something so it'd be like a custom convertor.
   -Any ideas?
    -CthulhuLuke

[kspiff]

Hm.. but why cram all that crap into a JAMMA rig when you can just rig up something else way easier?  I mean for one thing the PSX pads will just have a bunch of useless buttons and sticks.. and 2nd they don't feel very arcadey.. you should probably go old school and get a pad for a system from the previously mentioned list that doesn't use discrete signaling and has 4-6 buttons + a d-pad (keep in mind here that the JAMMA standard includes only 3 buttons [sometimes 4, but rarely].. buttons 4-6 generally attach via an auxiliary harness directly to the game PCB so you probably really only need 3 or a max of 4 if you plan to use solely regular JAMMA boards -- see Bob Roberts' site for an explanation of JAMMA/JAMMA+).

If I were you, I would just make some stout arcade sticks with some sheet metal on a routed wooden base.. neat controls and a neat rig with only a DB15 -> harness.

Oh, and as far as using a PSX -> USB convertor.. correct me if I'm wrong, but doesn't USB also use discrete signaling and have a pinout that would require yet another round of decoding before heading to your harness?  You'd probably need to make your own decoder board to read the PSX pads input, 'translate' it, and signal the proper wires on the harness!

[CthulhuLuke]

Yep, I see exactly what you mean, the reason why I'd do that is because my arcade cabinet literally has playstation outputs coming out of it, so it'd be easier than physically building a whole new set of joysticks.  And what I meant with the convertor was if anyone knew of a convertor that physically spliced up the psx data output, so that I could use it to convert to the jamma rig, not just a USB convertor, and I know that USB is also a custom set of data signals.  I was thinking last night I might be able to make a connector via a gameport input, because I've heard you can get exact signals from those, but I'm not too sure.  This probably won't be for a while, so by the time I get around to this, I'll probably have enough money to make a whole new set of joysticks specifically for a jamma rig.
  I think I'm just getting excited about this because I don't get my new computer until I graduate high school, which is in like another 4 monthes or so, and when I do I'll have a computer fast enough to run everything related to Mame and such, but for now I'm stuck with my 300mhz pentium 2 in my cabinet.
    -Thanks for the help though
     -CthulhuLuke