Help with final details to a supergun

aha2940

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Hi

I am finishing (at last!!) my supergun, which uses a Neobitz encoder. So far, I've tested it with Atomiswave, CPS2, MVS and a PGM boards. However I have some issues, and I'd like to ask here if somebody can help me please:

1. The video output is nice if I use composite, but if I use component video, the picture looks like "too bright". This happens with all boards I have tried. Should I put resistors in the RGB video inputs? if so, why does the picture look nice in composite mode? I do not have a TV with S-Video, so that's untested so far.

2. The PGM board does nothing. If using composite, I turned it on, it makes some music, but nothing is displayed on the TV. If using component, I turn it on, a kind of splash screen is displayed, then the TV says "invalid resolution". Is there a trick to make the PGM work with the Neobitz encoder? I do not yet have a cart to test, only the board.

3. The MVS sounds strange. I know it's not JAMMA compliant, and I should put a switch to change the supergun between MVS mode and JAMMA mode. However, I read that if the SG is in MVS mode, and you connect a JAMMA board, it may get fried. Is there a circuit to avoid this? I usually forget to check basic stuff, and I'm sure if I let it like this, sooner or later I'll fry the Atomiswave or a CPS2 by plugging them whith the SG in MVS mode.

4. Atomiswave and CPS2 have fans that are so damn loud. Can they be disabled, or at least make them spin slower? will this damage the boards in the long run?

I believe that's all. Sorry for the wall of text. Any help is appreciated.
 
Last edited:

mikey

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1. I find composite to be darker generally then component. I would recommend always installing pots to control RGB brightness no matter what, as some boards output hotter video signals then others, so it's handy to have either way. 500ohm to 1k pots per RGB line should work.

2. Sorry, can't help you with this as I don't have a PGM

3. Depends on the MVS board you're using. 1 slots are generally JAMMA compliant, so you should be fine if that's what you're using. I believe if you have a 2-6 slot board, you have to be careful of hooking up to JAMMA. I use my MV-1F and 1FZ without any adapters or switches on my supergun and have no issues whatsoever. You just need to ensure your MVS is switched to mono if it has the option, unless your supergun is rigged for stereo via a switch.

4. I swapped the fan out of my CPS2 for a quieter one, there's info all over the internet about it. It's quieter, but still not silent by any means. My atomiswave I left the fan in as well. They both have fans in them because they were meant to be powered on for long periods of time and are enclosed in plastic. If you're just firing them up for an hour or less of playtime, you *might* not need to fans in either system. Not sure if anyone else has taken the fans out and can verify they don't get too hot, but I would imagine it would be fine for shorter periods of time.
 

MuppeT

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http://www.jamma-nation-x.com/ carries the fan that you are looking for. It is not that loud.

Don't disable the fan on the atomiswave as without it will overhear quite fast and the results will be not pretty.
 

Xian Xi

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The quietest fans for CPS2 are the Pabst fans but be prepared to be raped as they usually go for $15+ each.
 

GohanX

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Not worth the cash imo, the JNX fans work great. I would like to find one for the Atomiswave though.
 

aha2940

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Thanks for your help guys, very appreciated. I think I'll take a look at James' fans and probably buy one for the CPS2, that thing sounds like a plane taking off. Any idea on the component vs composite video issue? should I get 500-1K potentiomenters (which value is better?) like the first answer suggests or are there any other solutions?

Thanks!!
 

aha2940

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Last edited:

Xian Xi

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Thanks for the info James. Very appreciated. I have another question: is it required to use three separate potentiometers for R, G and B? or can I use a triple potentiometer like this: http://www.ebay.com/itm/HP-Agilent-...427?pt=LH_DefaultDomain_0&hash=item20fc7c2f1b ? another question: since potentiometers have three legs, I assume they are connected like:

left - ground
center - output
right - input

Am I right?

Thanks!!

You can use a triple ganged pot but just keep in mind that if one of your boards has a color that is off, you can't individually tune the color to a different level. I always put input on the middle and output to one of the outside pins and the unused is connected to ground.
 

aha2940

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You can use a triple ganged pot but just keep in mind that if one of your boards has a color that is off, you can't individually tune the color to a different level. I always put input on the middle and output to one of the outside pins and the unused is connected to ground.

Thanks Xian Xi, I appreciate your help, but since I got a gonbes VGA video encoder, I think I will save the Neobitz for modding my AES or maybe my Genesis. That should need no pots, only fixed resistors, right?

Thanks!!
 

aha2940

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Hi

I'm glad to let you know that my supergun is finally working with audio! I even setup a switch to change between standard JAMMA mono and MVS stereo, however I have a couple more questions now:

1. Of all the boards I have tried (CPS2, Atomiswave, PGM, MVS MV1C), the MV1C seems to have a very low volume. I already set the pot to its max, but I still need to put the TV's volume to about 50-55, whereas the other boards output nice volume when the TV is at about 17-22. Anything I can do to it? recap is in order maybe?

2. My power supply (Meanwell RT125A) seems to have a minimum load of 2A to the +5V line, and since some of the boards do not load it so much, it whines with a very annoying high-pitched sound. I think the problem is the minimum load, because with high-amp boards (CPS2, Atomiswave) there is no high-pitch sound, but with low-amp boards (MV1C, PGM) the sound it's there. Any idea how to build a basic circuit that loads the PS about 500mA additional to the usage of the board?

Thanks!! I'll post pics of my franken-supergun when it's finally complete.
 

Xian Xi

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For the audio, what attenuation circuit are you using? The MV1C provides good level amped audio from the JAMMA edge.

For the power supply you can add a dummy load between +5v and ground using a high wattage resistor something like a 3ohm resistor. Just remember that it will need to be cooled since it will generate some heat unless you use something higher than 8watts prefferably since it will be dissipating just above 8 watts.

http://www.ebay.com/itm/QTY-2-10-wa...912?pt=LH_DefaultDomain_0&hash=item2576250e38
 

aha2940

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For the audio, what attenuation circuit are you using? The MV1C provides good level amped audio from the JAMMA edge.

For the power supply you can add a dummy load between +5v and ground using a high wattage resistor something like a 3ohm resistor. Just remember that it will need to be cooled since it will generate some heat unless you use something higher than 8watts prefferably since it will be dissipating just above 8 watts.

http://www.ebay.com/itm/QTY-2-10-wa...912?pt=LH_DefaultDomain_0&hash=item2576250e38

Thanks for the help, James. For the audio I used the audio attenuation circuit you describe on your site, a voltage divider made with a 10k resistor and a 1k resistor, the 10k is the input, the 1k goes to ground and the joint between both is the audio output. It sounds fine, just with low volume. Any ideas?

For the dummy load, I had calculated that a 10ohm resistor should do the trick, thanks for the wattage help.

Regards.
 

Xian Xi

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10ohm would be perfect for 500mA. I was only glancing over the post and saw 2A and 500mA without actually reading so I thought you were only loading with 500mA.

As for the attenuation circuit, you can build an adjustable one. Replace the 10K with a pot instead.
 
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