MVS / Supergun Problems

[Aypok]

First off: please excuse my stupidity in this post - I'm quite new to arcade hardware and I'm not all that great with electronics (I'm a software guy). On with my story/questions...

After reading through a few posts in this sub-forum (mainly the great thread spawned by Twimfy, which answered many questions I had), I decided to delve in to the world or arcade stuff. My plan was to get an MVS (I've always enjoyed Metal Slug and a few other games on the system) and a simple supergun. So I bought myself a cheap Vogatek supergun from another forum, then bought a nice 4 slot MVS system (with two games). The 4 slot seemed to have a few benefits over the 1 slot models and space isn't an issue - plus, it was cheapish.

I had read that, whilst the MVS systems are not 100% JAMMA compatible (I've seen the term "JAMMA+" applied to them), it was mostly compatible. Due to this, I figured my setup would work.

After firing up, in order, the PSU, the PSU plus supergun, the supergun plus empty MVS (which gave the expected grid test pattern) and, finally, the full setup with a game, it all seemed fine. I didn't get any sound through the TV, but plugging my headphones in to the supergun's headphone port did result in sound. Worryingly, there was a lot of other noise mixed in with it. At this point, I hadn't realised that plugging a standard JAMMA supergun in to an MVS unit can apparently destroy the sound amplifier (or something along those lines).

The second game worked fine, too, but starting it up with both carts in at once took me to the config/setup page (not a problem - everything seemed fine). It detected both carts, but I couldn't boot to either one - it only worked with one cart at a time. I put this down to the lack of a fourth button on my controllers and/or lack of the game-select button.

About six hours later, finished with work, I decided to fire it up again, but was greeted by the MVS's setup system each time. No matter what cart I tried, it always took me to the same thing (and selecting "Exit" from the menu just took me back there). One time it even gave me a Z80 error. It was at this point I started searching Google for some answers and realised that I may have damaged the MVS thanks to the supergun I was using.

Despite my Googling, I've not been able to find any solid answers to the questions I have; hence my post here. Here's what I want to know:

I'm pretty sure that I may have borked the sound system on the MVS: is this fixable? I've read that replacing the capacitors is simple enough (some people even sell kits), but isn't that something different to what I've likely damaged? I can use a soldering iron, but anything more than that may prove a little... challenging. I don't even have a multimeter, but am willing to spend a few quid to purchase one (and other such equipment - I have a soldering iron, though).

Is the system's inability to play games likely to be caused by using a JAMMA supergun instead of something more suited to the MVS? Or is it more likely that I just need to clean the contacts on the carts/board? Or is this the sign of a more serious problem?

When turing on the system (even the very first time I tried, with no carts), the first thing displayed is what looks like garbage. It only appears for a few seconds on a mainly green screen - and the pattern used to be the same each time (as far as I could see, at least). However, after the system stopped playing games, the pattern seems to have changed slightly (although still appears to be the same). Should I be worried about this? Or is it normal?

Assuming I've not completely trashed either my supergun or MVS, I'm planning on building (or buying, depending on the cost difference and my level of lethargy at the time) an MVS to JAMMA convertor. Is it worth it, or should I just attempt to build a simple MVS compatible supergun? I'm quite happy to follow guides on building things from veroboard/stripboard (and the like) -- it's something I've successfully done before -- but if it requires an actual knowledge of how it works, I could mess something up and make things worse.

I've got my supergun with me, but I left the MVS at work (which is where it is to live - much to the delight of my cow-irkers), but I can pick it up and take pictures/videos to show what I mean. If you need any more details or information, please let me know. Sorry for such a long post.

[Twimfy]

Are the games genuine? I'm not sure if faulty carts could cause this error but it's worth checking it out. I only ask because the green screen reminds me of the image that appears when MAME boots a rom with the decryption stripped and it only happens on Neo Geo roms.

[drakon]

http://www.hardmvs.com/html/PCBcompare.htm

4 slot uses the mvs style jamma pinout which isn't jamma compatible for sound. Unless you got the vogatek that's mvs pinout compatible. I purchased a mvs that's 100% jamma compatible and mine has stereo sound come out of seperate pins on the board. According to the above site the 4 slot can get stereo out of pins like mine does. So for sound I recommend you hook up to the seperate pins and not through the jamma port.

My MVS the setup menu only uses 3 buttons to navigate and the 4th button does nothing in that menu. I'm using a 1-slot so I don't know what issues you get with multi-slot mvs boards. I suggest you see if you can still get sound out of the pcb pin connectors. But I don't see how "borking" the sound would stop the games from playing. Some MVS's are 100% jamma compatible which I recommend for a supergun. Why they made the mvs pinout models use the same port as jamma I don't know, that was just stupid of SNK.

The inability to play games shouldn't be caused by the supergun. Only difference between jamma pinout and mvs pinout is the sound. Everything else is the same so you should be able to play games without sound. I had to clean my neo driftout contacts before it started working perfectly every time. Hopefully dirty contacts are the problem with your ability to play the games.

The garbage screen is normal. That's the system testing various things. Different games present different garbage. My samurai showdown 4 has 2 screens of garbage probably because it's larger than 330 megs. The only thing you can trash on a supergun is a rgb to s-video circuit. But you're not using that so your supergun should be fine (unless the guy who sold it to you trashed it somehow before selling it to you). But picture and sound on a vogatek are straight wired so there's really nothing to "trash".

You don't need to buy a mvs to jamma adapter. You can simply use the supergun for everything but sound and hook up sound to the pins from the board instead of through the supergun. But if you're unable to figure that out, then I guess a mvs to jamma adapter would be a good thing for you. Building a mvs compatible supergun would be a bit pointless because then you wouldn't be able to play anything else on the supergun. Learning how it all actually works is very key in building or even setting things up.

The green screen is normal and should always appear. Z80 error....that's not so good.

[retro]

OK, let's see....

As you've discovered, MVS is not JAMMA. This also goes well to highlight why the Vogatek can be a crappy option - lack of flexibility in some models!

Here's what's different:

• MVS uses stereo sound, JAMMA uses mono
• MVS uses an either audio header rather than the edge connector (should be CN6 IIRC - on the side of the board in the middle, between the joystick ports and volume controls) or is stereo wired on the edge connector
• JAMMA uses -5V, MVS does not (the pins shouldn't lead anywhere on an MVS so that's not an issue)
• JAMMA has a preamp audio output that is rarely used. Some rigs designed for televisions may use them.
• The audio ground pin on JAMMA is the test switch pin on MVS
• The speaker + and - pins on JAMMA are speaker L and R pins on MVS
• The tilt and test switch pins on JAMMA are extra coin switch pins on MVS
• The game select up and down pins on MVS are not used on JAMMA

You can see from the above that:

1. You need to wire your sound to the audio header, or to the edge connector in STEREO configuration
2. You need to wire switches to the game select up and down pins (26 and d i.e. the third pins from the edge furthest from the key)

On top of that, you need to ensure you have a fourth button wired up!

So... get a JAMMA fingerboard and an edge connector, and build yourself a harness!

http://www.hardmvs.com/html/jammaAdapt.htm

That, or buy one... e.g.:

http://www.jammaboards.com/store/neo.../prod_198.html

You can't select a game without the game select buttons.

The pattern on boot up is common in MANY games - the hardware is checking ROMs, basically.

A Z80 error isn't good if it keeps happening. If there is an error with the audio system, this error may come up. It can be caused by a faulty cart / bad connection (some carts have sound chips in them). Other than this, it means replacing the Z80.

You need to go into test mode and ensure that everything's OK. Does it recognize both carts at once? Is there any difference if you put the carts in slots 3 & 4? Sometimes there can be broken tracks on the board that cause errors where the carts aren't recognized.

You might have damaged your audio amp - let's hope not! Sometimes you can replace the caps in the audio circuit and that does the job, sometimes you must replace the amp (an HA13001).

Incidentally, is it an MV4, an MV4F or an MV4FT2?

I think that covered everything. Sorry for repetition of points already made - it was easier to just cover everything ;-)

[Jamtex]

Make sure the PSU is outputting 5V, plug the supergun in to the MVS and use a multimeter to see if you are getting 5V between +5V and a Ground. Do not measure the voltage without something attached to the Supergun as you will be wasting your time. If the voltage is >5.25V or <4.75V then your PSU is crap (and probably not adjustable as it is an ATX PSU).

Find a 74 series chip (it has 14 pins) on the far side of the board, opposite the JAMMA connector. Measure between Pin 7 and Pin 14, if you are getting less then 4.8V then you will find the MVS system may not boot up correctly.

If all that is good.

Make sure all the dipswitches are set to off.

Get a cartridge and use a pencil eraser to clean the edge connectors on the cartridge. You should see a lot of dirt come off, blow the excess off.

Plug cartridge into one of the slots (leave the other three blank) and turn on, if you still get green screen then try another slot, make sure the arrows line up on the cartridge too...

[Aypok]

Thanks for all the replies, guys!

Are the games genuine?

I honestly don't know, but I think they are. One of the games has a clear case and I can read "SNK" printed on one of the boards. A bootleg board could of course copy this...

Building a mvs compatible supergun would be a bit pointless because then you wouldn't be able to play anything else on the supergun.

Fair point, but I was thinking of having a dedicated MVS supergun which I could just leave connected to the system - freeing up my Vogatek system for anything else I may need in the future. Having said that, I don't think I'll be going in to normal JAMMA PCBs for a while - there are plenty of interesting MVS games to keep me interested for now. :)

Learning how it all actually works is very key in building or even setting things up.

I figured that would be the case, which is why I explicitly stated that I suck at such things. I have nothing against learning that stuff (in fact, I quite enjoy it) - the problem is I'm not very good at it. Heh.

You need to wire your sound to the audio header, or to the edge connector in STEREO configuration

If I go the former route (which, if I'm understanding you correctly, means simply using the MVS's sound output jacks - right?) instead of changing the supergun's setup, should I cut the supergun's audio lines (installing a switch in case I ever need real JAMMA stuff) - or just leave it wired as mono? That sounds like a stupid question even to me, but I'd rather be certain.

You need to wire switches to the game select up and down pins (26 and d i.e. the third pins from the edge furthest from the key)

On top of that, you need to ensure you have a fourth button wired up!

I think I'll just solder some extra switches on to the supergun, since they shouldn't affect normal JAMMA operation (as I understand it, from looking at pin-out diagrams). The plan to solve the fourth button problem was to simply buy some proper joysticks for it. It's the lazy solution, I know. :)

You can't select a game without the game select buttons.

The pattern on boot up is common in MANY games - the hardware is checking ROMs, basically.

Thanks for confirming those points. I was pretty sure that was the case, but this is all new and scary to me. :)

A Z80 error isn't good if it keeps happening. If there is an error with the audio system, this error may come up. It can be caused by a faulty cart / bad connection (some carts have sound chips in them). Other than this, it means replacing the Z80.

Thankfully, the Z80 error only happened once - subsequent attempts to boot the games didn't bring up this error.

You need to go into test mode and ensure that everything's OK. Does it recognize both carts at once? Is there any difference if you put the carts in slots 3 & 4? Sometimes there can be broken tracks on the board that cause errors where the carts aren't recognized.

The system does indeed correctly detect both carts at once, but I've only tried them in slots one and two. Broken tracks are a possibility: when inserting carts, the top board seemed to give a lot more than I was expecting. While there are support screws, they don't seem to be around the cart area, which seemed odd to me - but I'm sure there's a reason (too many tracks in the way?).

The only part of the test mode which doesn't seem to work fine (maybe - I have a feeling that it could be my stupidity creeping in again) are the sound tests.

When I choose the "left", "right" and or "centre" options, I hear no sounds - I'm expecting to hear test sounds. Obviously one of the channels won't work through my supergun, but I thought at least the centre one would.

By the headphones' volume control on the MVS, there are two 3.5mm jacks -- which I assumed were headphone jacks, but some things I've read say that these are not headphone jacks and that the 4 slot board doesn't actually have such things! Curse you, contradictory internet -- but I got no sound through either of those (with both volume sliders in various positions).

Incidentally, is it an MV4, an MV4F or an MV4FT2?

Yes. Heh. I'm not entirely sure at the moment, but I think it's an MV4F. I'm driving past my office tomorrow morning, so I'll pick it up then and confirm.

Make sure the PSU is outputting 5V, plug the supergun in to the MVS and use a multimeter to see if you are getting 5V between +5V and a Ground. Do not measure the voltage without something attached to the Supergun as you will be wasting your time. If the voltage is >5.25V or <4.75V then your PSU is crap (and probably not adjustable as it is an ATX PSU).

Find a 74 series chip (it has 14 pins) on the far side of the board, opposite the JAMMA connector. Measure between Pin 7 and Pin 14, if you are getting less then 4.8V then you will find the MVS system may not boot up correctly.

I'll go purchase myself a multimeter and check this out - thanks for the advice.

The PSU seems to be a generic and cheap-looking 300W PSU that came with the supergun. I've literally got a stack of other working ATX PSUs, so it's probably worth me trying one of them. Obvious, but I didn't think of it until you mentioned it...

Make sure all the dipswitches are set to off.

All but "free play" are off. I'll disable that and try again.

Get a cartridge and use a pencil eraser to clean the edge connectors on the cartridge. You should see a lot of dirt come off, blow the excess off.

Plug cartridge into one of the slots (leave the other three blank) and turn on, if you still get green screen then try another slot, make sure the arrows line up on the cartridge too...

Seating the cartridges the correct way around is the only think I know for sure I'm doing correctly. :) The metal shielding seems to prevent me from putting them in the wrong way around, which is an added bonus.

I'll give the carts a good clean and see how that goes.

Once again: thanks for all the replies - you've been very helpful (as always).

[drakon]

for what a vogatek costs it's NOT crappy. And you COULD mod it to support mvs if you wanted. Jamtex: I love the pencil eraser technique, works wonders.

aypok you don't need to cut the supergun audio lines. Just plug sound into the sound pins on the MVS pcb. They're not on the jamma port. The ones on my board are on the left side of the board next to my dip switches. Infront of my sound pins it says "speaker" and "headphone". I use the headphone one because the speaker one has traces going to the jamma port. My headphones jack is always on stereo mode. The speaker ones I'm guessing only go into stereo mode when I flick the switch on my mvs from "mono" to "stereo". But it's safer just using the headphone jack which works fine

retro. I didn't know there were different 4-slot revisions. I didn't find that info on hardmvs

also aypok AFTER I reviewed all the features of my mvs and realized it was the right model for me I read the manual to learn as much about it as I could

here's the manual for yours

http://www.hardmvs.com/manuals/MV2F-...viceManual.pdf

[retro]

You make any changes I mentioned on the fingerboard, not on the Vogatek. Similarly, if you don't want audio on the edge connector, you don't connect anything to those pins.

An MVS board shouldn't be used in a JAMMA cab / test rig without a harness - and vice versa.

As for the sound, don't do it! Think about it. The pins for JAMMA are audio negative and audio positive (i.e. go to the speaker). The pins for MVS are audio left and audio right. Therefore, you're hooking the left and right of the MVS to the speaker. A speaker is basically a coil, so you are effectively shorting the left and right channels together. The amp might not like that!

The pencil eraser trick should NOT be recommended. A pencil eraser is rubber - you're smearing rubber on the contacts and some residue will be left, impeding conductivity. It is also abrasive. Do it properly - use contact cleaner for general cleaning, and a fibreglass pencil for removing tarnish etc.

In effect, there were 2 major differences - the early (MV4) and the later (MV4F) revisions. The extra F revisions were minor differences. It is often argued what the actual difference is! Some think that some MVS revisions merely depict the country in which it was sold! For our purposes, the MV4 had a slightly different audio circuit.

Good point on the voltages - cheap PSUs often give out too low a voltage, even not under load! That's why arcade PSUs with variable +5V are the best solution ;-) The 4 slot takes a bit more current than a 1 slot, too.

[Twimfy]

Out of interest. Where did you get the Supergun from?

[Aypok]

also aypok AFTER I reviewed all the features of my mvs and realized it was the right model for me I read the manual to learn as much about it as I could

Thanks for the link, but I found that site/manual a few days ago.

You make any changes I mentioned on the fingerboard, not on the Vogatek. Similarly, if you don't want audio on the edge connector, you don't connect anything to those pins.

Makes sense. I've not made any changes yet; I'm still hunting a few things (made more difficult by the fact that my 'net connection literally drops every 30 seconds... </rant>).

The pencil eraser trick should NOT be recommended. A pencil eraser is rubber - you're smearing rubber on the contacts and some residue will be left, impeding conductivity. It is also abrasive. Do it properly - use contact cleaner for general cleaning, and a fibreglass pencil for removing tarnish etc.

Thankfully, my carts aren't here - so I've not yet tried this, either. :) I'll see if I can find some isopropyl alcohol or whatever it is people use to clean cart contacts - I assume that's the stuff you meant.

Out of interest. Where did you get the Supergun from?

From the same seller who sold you yours. :)

[retro]

You can use isopropyl, but I usually find the stuff sold as contact cleaner works best. You'll get it from Maplin or CPC.

I prefer to use contact cleaner than switch cleaner - switch cleaner has a lubricant, too. It would work, though.

http://www.solotechnic.co.uk/aero-kl...ml-i23508.html

That's just one example - you'll get shop's own brand from places like Maplin....

http://www.maplin.co.uk/Module.aspx?ModuleNo=25340

If the game is showing up always, I doubt it is a dirty contact, though. That said, it's worth a clean. Use a cotton bud.

[drakon]

I cleaned my neo driftout contacts with a t-shirt and some spit. Works like a charm now. I ran out of erasers

[Aypok]

I cleaned my neo driftout contacts with a t-shirt and some spit. Works like a charm now. I ran out of erasers

Heh, that sounds like how I clean my normal carts and consoles (Mega Drive, SNES, etc). I've got stacks of them, so don't care if they get damaged. :)

In other news: I picked up my MVS from the office this morning and found that the model is "MV4" - it's not an "MV4F" as I had stated earlier. Picture.

[Jamtex]

Yes an eraser is bad, but it does clean the crap from the edge connector if you don't have rubbing alcohol or contact cleaner (which is fairly nasty stuff) or even a fibreglass pen... It's also cheap and something that you are likely to have around, if I am lazy I will use an eraser and some cardboard and have never had a problem in the last 15 years in the business....

[retro]

LOL cardboard?!? Geez - that's super bodge job! :lol:

Umm, surely if you're a business, you should invest in the right tools and always have them to hand on your workbench?

For those who are interested in the pros and cons of erasers, here's an article by an eraser fan who looked at it in a somewhat scientific manner:

http://www.robotroom.com/PCBTarnishEraser.html

[Aypok]

The good news is that the last of the components (the finger boards and JAMMA connectors) arrived yesterday and I built a working interface... thing. The MVS now seems happy with several carts at once - more so now that I've added a "game select up" switch to it. :)

The bad news (well, it's not good news) is that I was stupid enough to kill the tip of my brand new soldering iron (much like Twimy did in his thread). Replacement tips are easy to find, so it's not a major problem. It just means I have to wait until I finish it (adding joystick connectors and making the actual joysticks).

I was planning to use the joystick ports built in to the MVS unit, but they seem really deep. The 15-pin connectors I bought don't seem to go in far enough to reach the pins... Oh well; the Vogatek's Mega Drive controller ports are sufficient for now.

Thanks again for the help, guys. It's very much appreciated.

[Twimfy]

Yay, glad you got it working. Which games do you have?

[Aypok]

Yay, glad you got it working. Which games do you have?

At the moment, just World Heroes 2 and Super Sidekicks 2 - I've not played either enough to know if they're fun or not. I know the former game gets a lot of flak...

I plan to get the Metal Slug games (naturally), along with a few shmups (Aero Fighters 2, to name but one). Plus any games my cow-irkers think are fun (which means there'll probably be a King Of Fighters game sitting in there, too). :)

[drakon]

At the moment, just World Heroes 2 and Super Sidekicks 2 - I've not played either enough to know if they're fun or not. I know the former game gets a lot of flak...

I plan to get the Metal Slug games (naturally), along with a few shmups (Aero Fighters 2, to name but one). Plus any games my cow-irkers think are fun (which means there'll probably be a King Of Fighters game sitting in there, too). :)

oh, so is the sound working? For world heroes I really like World heroes perfect. The game's a total joke but pretty fun. Samurai showdown 4 is also awesome however lately I havn't seen many copies of it floating around.

*edit* nevermind there seems to be copies of it on ebay now

[retro]

The 15-pin connectors I bought don't seem to go in far enough to reach the pins... Oh well; the Vogatek's Mega Drive controller ports are sufficient for now.

If you bought standard 15 pin sound card game leads, they should work, but sometimes they needed a bit hacked off! Give it a go ;-)

Take a look at the pic here:

http://cgi.ebay.com/2-Neo-Geo-Joystick-6'-Extension-Cables---JAMMA-MVS-AES_W0QQitemZ150330485579QQcmdZViewItemQQimsxZ2009 0305?IMSfp=TL090305128008r14089