MVH (4 slot) CMVS how to do the 5v+ mod and Stereo mod? Audio signal is super low

[Tengugurl]

Hi everyone,

I am making a CMVS 4 slot (US model) and I got the board powered off of 5v+ 6AMP 30W working well enough minus Audio. The video signals are decent (Via the Jamma edge) - Well near the Jamma Edge (There must be a better location, please let me know if such a place exists)

Now I am onto to the Audio and I am piggybacking off the headphone 4 prong white adapter port on the left side of the board (near the Audio Caps). (Far left is Left Channel middle to prongs is Ground and far right is Right channel)

I am getting a very very faint sound from the board and I am assuming this is because I am not powering the 12v+ needed for the Stereo AMP (Something??).

I did a complete CAP kit a year back and if I place it back in its original CAB the audio is just fine through the stock speakers. So nothing is broken thank the old Gods and the new.


May I pick your brains?

1) How do I do a stereo mod for a MVH 4 slot?

2) Do I need to do the 5v+ mod? (What does this do for me benefit wise? http://www.jamma-nation-x.com/jammax/tutorials.html#MV45v

3) Do you have any pics of where I should solder for the R,G,B,SYNC signals on my board (Tried the Resistors and no dice, so I ended up soldering near the JAMMA edge)

4) Last silly question, will it hurt my board to have -5V going through the NEO GEO MVS PCB?
(This is a side question as I am only powering it through 5v+ 6AMP 30W but I have been curious if -5v to the JAMMA edge would do any harm) (If I put 12v in a 5v+ only modded PCB will it damage my system?)

As always,
Thank you so much for your help.

You are helping a Neo Geo Fan girl level up her soldering skills by +2 dexterity and 3+ intelligence +1 conversation abilities

 

[Xian Xi]

I didn't see it in your post but did you adjust the volume slider for the headphone out?

 

[Tengugurl]

Hi! thanks for your help

I do have the volume up, sadly...
I got it pretty close to max volume on the headphones (didnt want to go too loud as it might blow) but when it is near to max volume it is super quiet

It could be the crappy wire I am using? (The chain goes as follows: PCB Solder point to fuse to rca female to rca/3.5mm conversion to 3.5mm cable)
I will try with some 22 AWG...

Should the headphone jack/ channels work without the 12v+? (One would think?)

 

[Xian Xi]

What model 4 slot is it? If it's the FS then you don't need to do the +5v mod. Basically if the bottom board DOESN"T have a 7805 then you don't need to do the mod, but if it has one then you need to do it. Also don't forget to use fader lube on the volume slider tracks, nothing else.

 

[Tengugurl]

Hi again,

On my board is says MVH - 4 slot. My bottom board has a 7805 (I am assuming but would you be able to confirm if this image is the 7805)

I will most definitely be purchasing some Deox fader lube from Amazon and clean the board up.

So if that image is correct, I guess I have a 7805 regulator and will need to do the 5v+ mod, correct?

If so, would this be the best place to do the bridging:
http://www.jamma-nation-x.com/jammax...als.html#MV45v

Sorry for all the questions, just learning is all....

What does the 5v+ mod do besides allow the board to be used off of 5v+ only? (Does it do anything for Audio? - like the stereo mod I have been reading on?)

 

[Xian Xi]

Yes, that's a 7805. Easiest place is on the YM2610 as it's connected to both the main and secondary +5v rail. You just have to run a wire between each pin. Use a multimeter to find out which one is connected to the main and one that is connected to the secondary rail.

If yours is the same as in the tutorial, use that for the mod.

 

[Tengugurl]

Thank you so much for your help Xian Xi! You are the best!!!

I was able to follow the tutorial here:
http://www.jamma-nation-x.com/jammax/tutorials.html#MV45v

I scratched away until I could bridge those two areas together, then I removed the 7805 and poof!! it works perfectly!

Yay! I have a CMVS of my own.
Have a lovely rest of your day and thanks for always being so helpful.

 

[Tengugurl]

Oh oh oh! last thing....

Would anyone be able to answer the following questions?

1) Will it hurt my board to have -5V going through the NEO GEO MVS PCB?
(This is a side question as I am only powering it through 5v+ 6AMP 30W but I have been curious if -5v to the JAMMA edge would do any harm)

2) If I put 12v in a 5v+ only modded PCB will it damage my system?

3) Do you have any pics of where I should solder for the R,G,B,SYNC signals on my board (Tried the Resistors and no dice, so I ended up soldering near the JAMMA edge) this is for a 4 slot MVH (First run board so the old one)

Thanks
I just want to hide the wires all tricky like instead of having them peak out through the Jamma edge

 

[Xian Xi]

Oh oh oh! last thing....

Would anyone be able to answer the following questions?

1) Will it hurt my board to have -5V going through the NEO GEO MVS PCB?
(This is a side question as I am only powering it through 5v+ 6AMP 30W but I have been curious if -5v to the JAMMA edge would do any harm)

2) If I put 12v in a 5v+ only modded PCB will it damage my system?

3) Do you have any pics of where I should solder for the R,G,B,SYNC signals on my board (Tried the Resistors and no dice, so I ended up soldering near the JAMMA edge) this is for a 4 slot MVH (First run board so the old one)

Thanks
I just want to hide the wires all tricky like instead of having them peak out through the Jamma edge

1. No, because the -5v trace doesn't go anywhere on the MVS board.
2. No, the 12v only powers the speaker amplifier so it can still be used in a cab.
3. If you look at the pins for RGBS and use a multimeter, you can see where you can tap it from the resistors. Very easy to find.