The Supergun discussion and Q&A thread.

[Elgen]

I've just finished making myself a SuperGun build into the case of an old SegaMasterSystemII-box. Pictures of the process can be found here (public Facebook gallery with danish comments, sorry): http://www.facebook.com/album.php?aid=1 ... d171261ea5

For controller connections I use SUB-D 9-pins, as I don't have any fighters or any other games that use more that 3 buttons. I therefore have 4 directions, 3 buttons, start og coin (I'm cheating a bit by not having a dedicated ground-leg, but use the shield of the cable instead).
The controllers I use are 2 Namco-sticks modded to be used for any console by the use of external adapters. Pictures of that process can be found here (public Facebook gallery with danish comments, sorry): http://www.facebook.com/album.php?aid=3 ... 12d326df8a
I might make some new controllers with the same pinout and some nice Sanwa-parts or something in the near future. I will then be able to use them with my consoles as well as my SuperGun };-P


Tell me what you all think; I'm pretty satisfied with the results myself };-D

PS. Just a heads up. I used acetone to remove the paint from the vizor and it works well; don't use it on the console itself cause it melts http://www.facebook.com/photo.php?pid=2 ... 1390686556 (this is not the SuperGun, but another console I used for testing };-D)

[XianXi]

You might want to redo your power wiring, that's too small a gauge for the higher amp games. Other than that it looks really nice. Good job dude.

[Elgen]

Do you refer to the flat cable or the grey wires inside the box? Well the insides I know is a bit on the small side; I am planning to get some lager ones installed };-D
For the flat cable I did think about that problem and have wired ALL legs of the JAMMA. That way I have 4 parallel wires for +5V, 2 for -5V, 2 for +12V, 8 for GND; I think that ought to do it. And if I should get problems with overheated flat cable, I could disconnect 8, 9, J, K, 25, 26, c, and d from their respective JAMMA legs and use them fo +5V as well. As I don't use them anyway. So I don't think that'll be an issue. But thanx for the interest in the project };-D

[XianXi]

There is no way 26-28 gauge wire can pass 30+ watts of power without frying some insulation. Change the wire gauge for the power wires going to the jamma edge. This is just my recommendation of course so it's up to you if you want to do it.

[mojo]

I think what Elgen is getting at is that because there are multiple wires for each voltage and ground he thinks that the ribbon cable will be enough, but I too have to disagree.

Even assuming that all games use all the available pads (and you can bet that some don't) I don't think it would be enough. Best thing to use is mains flex. It is cheap and easy to work with. They also list the maximum wattage on the cable in most cases (or in the shop) but even the smallest lamp cord should be capable of 60W or more.

[Elgen]

Well offcause I've connected all the 5V-wires at both ends, otherwise I wouldn't be sure, that it was true parallel, as you mention with the pads. The same goes for -5V, 12V and GND.

Now science comes to the rescure };-D

According to Ohm's (http://en.wikipedia.org/wiki/Ohm's_law) and the definition of electrical power we get

P = I * U = I * I * R = I^2 * R

so the power in a wire is I^2 * R, where R is the resistance in the wire and I is the current in the circuit.

Now using (the special case of equal size resistors) of the law of parallel resistors (http://en.wikipedia.org/wiki/Resistor#S ... _resistors) we get, that using n resistors of equal size i parallel, the total resistance is R/n, where R is the resistance of one of them. Thus, as the maximum current I can draw from the PSU without popping the fuse is 10A at the 5V terminal (P = 50W), the power in the wire can be at most 50W. Now using 4 wires in parallel means that each wire will have a power of at most 12.5W. And I still have more wires I can add, if I see a problem comming };-D

[mojo]

True enough Elgen, it's just that us engineering types like to go for 3x required spec on our own projects, just to be sure

Seriously though it is less of an issue with low voltage stuff but it is still wise to over-spec. You need to account for things like potential short-circuits which could cause severe melting or even a small fire. Again it is less of an issue if your PSU can't put out more than 30W but for the sake of safety I would still overestimate. Electricity does not flow evenly over wires connected in parallel, or even a single cable made up of multiple strands of wire.

It is a nice build though. How do you find plugging the JAMMA edge connector in and removing it? I put some cable ties in loops on mine to help unplugging. The use of a console case is a nice touch, keeps everything neat and tidy.

[XianXi]

Well offcause I've connected all the 5V-wires at both ends, otherwise I wouldn't be sure, that it was true parallel, as you mention with the pads. The same goes for -5V, 12V and GND.

Now science comes to the rescure };-D

According to Ohm's (http://en.wikipedia.org/wiki/Ohm's_law) and the definition of electrical power we get

P = I * U = I * I * R = I^2 * R

so the power in a wire is I^2 * R, where R is the resistance in the wire and I is the current in the circuit.

Now using (the special case of equal size resistors) of the law of parallel resistors (http://en.wikipedia.org/wiki/Resistor#S ... _resistors) we get, that using n resistors of equal size i parallel, the total resistance is R/n, where R is the resistance of one of them. Thus, as the maximum current I can draw from the PSU without popping the fuse is 10A at the 5V terminal (P = 50W), the power in the wire can be at most 50W. Now using 4 wires in parallel means that each wire will have a power of at most 12.5W. And I still have more wires I can add, if I see a problem comming };-D

LOL

The wire meaning the metal strands can handle the current but like I said you will fry the insulation resulting in the wires shorting once the insulation is gone. The heat produced from high current will easily melt that insulation.

[Elgen]

@XianXi: Could you name me a few of these high amp boards you mention, as I have never come across any of them yet. I also havn't been able to find a list anywhere that states how much current each board draw in average; would be a nice addition to ei the KLOV-db though.

[XianXi]

Usually the bigger the board = more amperage, usually. If the board is populated with a lot of socketed chips usually you can expect to be using at least 3-4A on the +5v line. Boards like a Neo Geo 4 slot with all high meg games in all 4 slots pulls around 5.5A on the +5v line.

If you stick to smaller boards you might be able to get away with it but from my experience the second it's a high draw board the insulation melts pretty damn quick, just hope nothing shorts out when that happens.

[mojo]

Early games tend to be quite high draw as well due to having a lot of individual logic ICs based on old technology. Also keep in mind things like inrush current and audio amplifiers can pull quite a lot. For most electrical needs it is generally a good idea to plan for 3x the required current unless there is a good reason not to. The place I work calculates inrush current but only doubles it, mainly to keep costs down. Every now and again though a cable gets damaged by over-current and being as they are installed in buildings replacing them is very time consuming.

[spudgun]

Hi,

Just joined the world of Supergun but have hit a hitch already. My Supergun device has a 9 pin Dsub connector to an RGB scart. None of the tv's in my house were compatible except for the Sharp HD LCD in the front room. It works fine with my Jamma boards through this TV but it's not practical.
So I got hold of a cheap-ish Samsung 32" CRT with an RGB scart in. The picture shows but it's very broken up, almost split diagonally in the middle. Basically unplayable. I was told an RGB-scart equipped telly would be required, what is the problem here anyone ?

**edit**
Update. My Taito 'Football Champ' works fine on the living room Sharp HD tv but is the one causing the jittery display problems on the Samsung. So I tried some other boards, firstly Double Dragon which I knew to be working with display faults. Sure enough the Double Dragon startup screen appears, perfect. The character sprites are missing, obviously a board problem but the display is rock solid. I then tried Pitfighter, a game I knew to be working fine, and it too booted up and looked really good (even for Pitfighter). I would normally have assumed the Footy Champ board to be defective, except it works on the other TV. I'm not up on the electronics side but is this some issue with the freq put out by the Footy Champ board that my Samsung isn't liking ?
Any help much appreciated.

[mojo]

The problem you are having is most likely down to the games not being PAL or NTSC, but something in between. PAL is 50Hz and NTSC is 60Hz. Most TVs support both of those. Many arcade games are something odd like 57Hz or 48Hz though, and most TVs don't properly support them. Arcade monitors will, but with TVs it is hit and miss.

For example I have an original PacMan board which runs at 57.5Hz. On one TV it displays but the on-screen channel number is permanently there and can't be removed with the remote. On another cheap little 15" screen it works fine though.

So basically you will either have to get an arcade monitor or find a compatible TV. There are lots of charity shops that sell CRT TVs for next to nothing now so you can try a few out, and if you ask nicely they might even allow you to test a few in the shop. You can also try eBay. Look out for "broadcast monitors" which are basically TVs with extra controls and flexibility as they are often compatible with arcade games. I have an NEC XP29 Plus but many Sony PVR units are suitable too. They can be quite expensive though.

[spudgun]

Thanks for the info. Had a feeling it was something along those lines. Problem is I just got this Samsung for such a reason, and it does display my other boards really nicely. Wasn't wildly expensive but it took me a while to talk the other half round into getting another tv in my games room. I alread have a lovely large Toshiba rear projection unit, but that has just S-video inputs. Is there anything else I can do at all to modify these frequencies or convert them into S-video (inferior, I know) to get them working on either of these tv's ?
I'd rather spend any more dosh on getting another Supergun, perhaps with S-video out so I can split my boards between the two TV's, respective of which board runs on which telly.

[mojo]

There is unfortunately no way to convert the frequency. You might have luck with an RGB SCART to VGA converter and a VGA monitor, but then you might as well just get a compatible TV. Conversion to S-Video won't help at all.

You can get a 32" Toshiba for about £35 in my local charity shop. PITA but probably your only option.

[XianXi]

The only way to change the frame rate is by using an XRGB3 in B0 mode I believe but that costs about $400.

[spudgun]

Hey, thanks for the suggestions. Here's the good news. I have the thing working perfectly ! (almost), a little naivety on my part. It's been a few years since I tried out my boards as my cabinet monitor was dying and I had no way to test them. So they've been in storage for about 6 years, apart from my beloved Footy Champ board which I kept on standby for the day I either got a new cab or a Supergun. So of course I was testing the tv's with this board ONLY. It was badly flickering on the Toshiba and only slightly better on the Samsung I bought specifically for the Supergun (only £50 and it's a nice set, phew)

Today I happened to clear out the utility room and I found the manual for my Toshy tv, and it stated Scart 1 was RGB ! I stuck my Double Dragon board into the Tosh through RGB and WOW ! Perfection. I tried Footy Champ and yes, it flickered all over. Stupidly I had tested everything with the Footy Champ board.
Anyway, the great news after this ramble is that the Toshiba is a huge 46" rear projection tv and R-Type etc look fantastic on it. The only slight problem is that I want to use my Jamma extension lead to save wear and tear on the Supergun connector but, although the picture is good through this lead it emits a loud buzz.

That aside, it's a beautiful combo !
Thanks again.

[alamone]

Well, I might as well post mine.



"Jamma Biscuit MK-II"

A supergun shoved into a NES case.
Uses 2x 15 pin d-sub for controllers. I have a HRAP SE MC Cthulhu and a Saturn pad hacked for 15 pin d-sub.
Arcade power supply (HAPP) with adjustable +5V. Power on/off switch on the back, uses standard PC power cable.
Outputs line-level audio and RGB only through 9-pin d-sub.
Goes through an XRGB-2 and to a CRT.

One thing that I think not many people mention is that you have to tie logic ground
to earth ground, otherwise you get interference (diagonal scrolling lines or jailbars) in RGB.
Basically, tie GND from the JAMMA harness to the GND pin on the 3-prong AC line connector for the PSU.

[mojo]

Nice work alamone!

Basically, tie GND from the JAMMA harness to the GND pin on the 3-prong AC line connector for the PSU.

That is interesting... I thought most PSUs tied their output grounds to the AC ground anyway, assuming they actually have an AC ground. Most PC PSUs seem to, sometimes with a 1M resistor. Did you tie video ground to your main ground?

This kind of knowledge is worth it's weight in gold.

[alamone]

Specifically this is the PSU I used:
http://www.happcontrols.com/powersupplies/80006400.htm

I removed the metal casing, drilled mounting holes in empty areas of the PCB,
screwed it down to the existing screw holes in the NES case, attached
a 80mm fan to the side to cool off the heatsink, and cut some vent
holes in the NES case for the fan.

There's three groups of grounds coming from the JAMMA harness (PWR gnd, Video gnd, Controller gnd).
Route them separately but tie them all together at the point of termination,
hook them to the second and third GND screw terminals on the PSU,
and then link that to the earth GND (third pin from the bottom in the photo) using some fat gauge wire.

Before I linked the logic GND and earth GND, I had some really bad scrolling diagonal line video interference,
but after putting the wire in-between the picture became crystal clear.

[mojo]

The case was probably being used to connect AC and DC grounds. I thought it seemed odd

[XianXi]

Just remember that not all outlets have a proper FG, some use a double neutral hookup if the wiring in the house is old, and that won't end well.

[alamone]

The case was probably being used to connect AC and DC grounds. I thought it seemed odd

While the casing was screwed to the heatsink, I don't know if it was linked to both grounds.
It's true that I removed the casing in order for it to fit into the NES case. In any case, doesn't hurt to add the grounding wire in.

[Daytime Dreamer]

This might be a noobish question but here goes :

I have a supergun which I want to connect to a plasma TV. Its a panasonic 46S20E

Does it accept the supergun's signal? Supergun i think is 15khz (might be wrong here, cant remember for sure)

Would a normal RGB scart to VGA adapter work? Would it produce lag?

[ZOM]

^This depends on the PCB you're hooking to it and how good your Panny supports the more "exotic" vertical refresh rates.
I don't know that exact model of TV you're using and often it's a gamble anyways, but you can lookup somewhere like maws for the games you intend to play on it and check on the frequency they're using; if its very close to 60Hz, chances are high it'll work.

[Daytime Dreamer]

^This depends on the PCB you're hooking to it and how good your Panny supports the more "exotic" vertical refresh rates.
I don't know that exact model of TV you're using and often it's a gamble anyways, but you can lookup somewhere like maws for the games you intend to play on it and check on the frequency they're using; if its very close to 60Hz, chances are high it'll work.

For Final Fight PCB the frequency is 59.610000Hz so maybe it will work. Hammerin Harry on the other hand is 55.X so maybe not?!

I'm not home right now and i cant find the tech specs for the panny online so no idea of what vertical refresh rate it supports

[Fudoh]

you've got a consumer Panasonic plasma without a VGA input, so there's no chance that anything "off" the standard frequency is supported.

On the professional Panasonic plasmas the VGA inputs are quite forgiving.

To run a supergun on your current TV you need a processor which will accept the PCB's refresh and output a standard 59.94Hz HDMI signal, e.g. a DVDO processor / scaler.

[Daytime Dreamer]

So whats the best option for a scaler? DVDO edge? I'm looking for a solution with the least input lag

Also, where can someone find a DVDO edge? Ebay?

[mojo]

Generally speaking what are people's experiences with LCD/Plasma screens that have VGA or SCART inputs? I will test my two Samsung TVs out later this month and report back here.

[xavierjesus]

Posted this Q over at AO, but thought I'd hit y'all up here.

I need a test button on my Vogatek supergun ASAP (to get at Ibara 'secret-super-special' Version - I wants to see me some rank etc.)

So, to all y'all tech-hedz, tell me where I needs to be soldering the wires below. Thanx in advance. And keep in mind I'm retarded when it comes to this stuff lolzerz...





Thank you please.