Other Probs With MVS Electrocoin UK

Hi, as of my other post, I have furthur problems with my cab.

1. Ive tried playing a game for the 1st time (its a jamma game). It works however if I put money in, it just comes out the coin return and doesnt actually register.How do I sort this as its a pain to keep pressing the service button for credits as I need to leave the bottom door off and sellotape the tamper switch shut!

2. Ive left the cab on for a while but the screen is rather blurry with thin white lines running across it horizontally. When I tried the cab out b4 I bought it it was very clear. Is there anything I have done wrong or I can adjust? Also, is it possible a dirty jamma board could cause this?

3. I have no sound at all. How do I get this running ? I am electrician and no how to use a multimeter but cant find anything in the cab that indicates control for the volume.

4. I have no credit lights, no coin entry lights, no marquee lights and no led lights (in the middle screen- I think). How do I get this running again?

Many Thanks In Advance.

1. First see #4 then check, does the coindoor have a coin mech? If so, it may not be adjusted for quarters and likely set up for tokens. Hopefully you have one that is adjustable (most are.)

3. Check out the jamma pinout at hardmvs.com. There are both an MVS and a Jamma pinouts listed there. It will tell you which pins are giving you your sound. Check the power supply and verify you are getting the 12 vdc from it (could be the problem for sound and coindoor.) Then just going to have to trace them through cab to verify there are not brokens spots. If there is a volume control, check setting on it and whether it is working or not.

4. Again, power for the lights on the coin door and such, you are going to have to trace things. Sounds like you are not getting power to anything on the coindoor. The pinouts found at hardmvs.com will be a big help for you. Likely your credit problem (#1) is that the coin switch on the mechs is not getting power.

I am about to check the voltages.

Another problem...

I have a 6 slot mvs board with 6 different mvs neo games that I put into each slot. Plugged the harness in but monitor stays blank and no sound. What could be wrong? Ive read about a test screen or something. Does anyone know where to start?

mvs..

Answer to No 3 in your first post, you will not a find a volume control. the speakers are wired direct to the jamma harness. your cab speakers are not wired for jamma, they are wired for mvs.

all the answers to your questions are in this tech forum, use the search function at the top and you will find all you need to know.

For test purposes, you do not need carts inserted, the MVS will boot to the cross hatch pattern if all is well.

First thing to check is the 5 volt pins on the jamma/mvs edge connect- they get hot and toasty on the MVH6 and lead to intermittent or no boot up.

absvicandmark said:

I am about to check the voltages.

Another problem...

I have a 6 slot mvs board with 6 different mvs neo games that I put into each slot. Plugged the harness in but monitor stays blank and no sound. What could be wrong? Ive read about a test screen or something. Does anyone know where to start?

Click to expand...

OK just checked voltages and fuses. I think my multimeter is playing up as where I expect 5v I get 0.5v (?!). However, I found a fuse blown in the main psu which was connected to 12v so replaced fuse and now have very loud distorted sound!!! Also noticed the neo geo marquee lit up. Didnt check coin mech as it was too loud and I turned it straight off!!!
How do I sort this volume out? Is there a way to turn it down as cant find a pot on the jamma game board or on the cab.

Also noticed that there was a purple wire connected to the 5v Neg pins. It seems there is neg 5v there as well (though my meter showing -0.5v! - The meter wont change range!).

If I can get this volume down then I can check the coin mech.

Please help as im finally getting somewhere!!!

absvicandmark said:

OK just checked voltages and fuses. I think my multimeter is playing up as where I expect 5v I get 0.5v (?!). However, I found a fuse blown in the main psu which was connected to 12v so replaced fuse and now have very loud distorted sound!!! Also noticed the neo geo marquee lit up. Didnt check coin mech as it was too loud and I turned it straight off!!!
How do I sort this volume out? Is there a way to turn it down as cant find a pot on the jamma game board or on the cab.

Also noticed that there was a purple wire connected to the 5v Neg pins. It seems there is neg 5v there as well (though my meter showing -0.5v! - The meter wont change range!).

If I can get this volume down then I can check the coin mech.

Please help as im finally getting somewhere!!!

Click to expand...

The volume and headphone level pots are on the bottom board (bottom LHS)

do u mean the bottom lhs of the mvs mobo as Im not using that at the mo, im using normal jamma board (TMNT 2 P). I read about the stereo/mono issue with mvs/jamma boards but as my harness already has -5v then is it possible that they are already mono? What would it sound like if I plug the jamma board in but the harness is still stereo? As the fuse was blown I suspect that it may not have been converted. How can I check if they have been or not?

Using a diagram on here I found that the speakers were still wired as stereo SO using another diagram I found, I rewired the speakers as mono with a volume pot (maplins, log cant remember the resistance I think about 150 ohms).
While I had the soldering iron out I found that the test key was wired as mvs standard so resoldered this to jamma standard.

Powered up with TMNT and found that I have to adjust the new volume pot by very small amount to get the desired effect. GREAT! Now I have volume adjustment BUT even though the sound is now turned down, it is still very distorted. Its better but still not very clear at all. At least I managed to try the coin slot and that now works perfectly.

Just need to get this volume sorted. Could it be just the one jamma game that im using? Its playable now but still very distorted at low volume.

Im gonna keep this as jamma so if anyone is interested in my 6 slot MVS board with 6 neo games as described in the sell it section then let me know.

absvicandmark said:

do u mean the bottom lhs of the mvs mobo as Im not using that at the mo, im using normal jamma board (TMNT 2 P)

Click to expand...

1.Sorry I thought you were.

2.Regarding the mono/stereo issue, most (just about all afaik) jamma boards do not have one side of the speaker grounded, (older games like Pacman or Galaga do).

See the difference in the HA13001 mono/stereo options here, it is self explanitary. In mono the device is run in a boot-srapped configuration like push-pull.



Depending on the jamma boardset, the outcome is different. Some will have no sound, others distorted sound. My Truxton board running in an mvs cab has perfect sound but the audio output IC runs stinking hot, Im sure it will fail if I run it long enough.

So to cut a long story short, it is possible that a jamma boards audio output IC could fail (vcc short to ground) run in an mvs cab and as a result take the 12 volt rail with it.

Hope this answers the question.

thanks for the reply, however its all gone through one ear and come out the other!!!
I converted the stereo L & 10 pins so they are now running mono BUT the sound is still distorted even though I can turn the overall sound down using the vol pot I installed (turns down but still distorted quiet - if that makes sense).


How do I stop the distortion?

soz to sound thick but im new to electronics.
I can solder and thats about it!!!

sorry about the tech thing, get carried away sometimes. Check the 12 volts, if low it may cause distorted audio.

Plenty of voltage now at the 12v pin. Marquee is now lit up and coin slot now works as it should. But music and speech is still distorted.

BTW - On a side note, i am using TMNT 2P jamma board. Does anyone know what dips do what so I can adjust things like difficulty and the amount of coins needed for a credit.
Id like to find this out for all my jamma boards. Is there a site that tells you what every jamma board dips are?

http://www.crazykong.com/dips/TMNT.txt

http://www.crazykong.com/

OK. Put another jamma board in (Bad dudes vs Dragon Ninja) and the sound is great!!! However I have to adjust my volume pot by very miniscule amounts otherwise its too loud or too quiet. Why is this? It is a log 150 ohm volume pot if that helps. Maplins told me that its the right one for the job but im not sure.