No Audio on Neo-Geo MV1-C (large pics)

jeffslot · Post by **jeffslot** » Sun Oct 26, 2008 5:00 am

Hi guys,

My video is working great (RGB on PSONE), even my d-pad is AOK. I can't seem to get my audio going though. Any suggestions will be helpfull.

Mv1-C

By classicvideogame at 2008-10-26

Back of psone screen

By classicvideogame, shot with Canon PowerShot S400 at 2008-10-26

hailrazer · Post by **hailrazer** » Sun Oct 26, 2008 5:45 am

Don't you need to solder all three of the headphone connections together to bypass the headphone jacks so audio will go through the speakers ?

jeffslot · Post by **jeffslot** » Sun Oct 26, 2008 6:49 am

Hailrazer,

I checked the book (benheck's) and it only said to do the two that I did. I also originally though it was all three so that is the way I did originally - I can try it again that way as I am getting desperate. I'll let you know what happens, thanks.

Jeff

Mario · Post by **Mario** » Sun Oct 26, 2008 8:53 am

jeffslot wrote:Hailrazer,

I checked the book (benheck's) and it only said to do the two that I did. I also originally though it was all three so that is the way I did originally - I can try it again that way as I am getting desperate. I'll let you know what happens, thanks.

Jeff

Try it. On my portable, I soldered all three together and it works just fine. Ben's book had a few mistakes, that might have been one of them...

jeffslot · Post by **jeffslot** » Sun Oct 26, 2008 9:01 am

I did try, it didn't seem to make any difference.

Jeff

Mario · Post by **Mario** » Sun Oct 26, 2008 9:13 am

Make sure your Neo-Geo is outputting audio. Hook it up to a regular TV screen. If that doesn't work, you either soldered in the wrong place, something is wrong with your wires, or your NG is broken. If the audio does work on a TV, try re-soldering the connections on the PSone screen. Maybe it was a bad solder joint. If the audio still does not work on the PSone screen, consider using an external amp. (Like from computer speakers)

EDIT: Doh! I just realized something. Make sure you attach video as well. The PS1 screen will not give audio without video.

EDIT AGAIN: I just read you were doing RGB. So your video is working fine? Try hooking composite up to the spot on the back of the board and see if audio works then.

jeffslot · Post by **jeffslot** » Sun Oct 26, 2008 9:26 am

Hooking up the neo geo to a tv would require major work & components I don't have righ now as the neo-geo doesn't ouput composite. There is no issue currently with the video.

The below comment you made is interesting, where did you see that?

The PS1 screen will not give audio without video.

Jeff

Mario · Post by **Mario** » Sun Oct 26, 2008 9:34 am

jeffslot wrote:The below comment you made is interesting, where did you see that?
The PS1 screen will not give audio without video.
Jeff

I've experienced it.

So you can't get composite from the NG easily? There isn't just a couple pins you could solder to?

jeffslot · Post by **jeffslot** » Sun Oct 26, 2008 10:04 am

So you can't get composite from the NG easily? There isn't just a couple pins you could solder to?

No, you need a video enoder.

Jeff

Mario · Post by **Mario** » Sun Oct 26, 2008 10:10 am

Well, that's OK, you don't need the video on a regular TV. You do have one, right? Try the suggestions in my earlier post:

Make sure your Neo-Geo is outputting audio. Hook it up to a regular TV screen. If that doesn't work, you either soldered in the wrong place, something is wrong with your wires, or your NG is broken. If the audio does work on a TV, try re-soldering the connections on the PSone screen. Maybe it was a bad solder joint. If the audio still does not work on the PSone screen, consider using an external amp. (Like from computer speakers)

arfink · Post by **arfink** » Sun Nov 09, 2008 1:48 pm

OK, I have run into this one before with my MV-1B. Does your RGB output actually work right now? If it does that's good. I would suggest going to HardMVS.com and picking up a PDF of the MV-1C manual and do a quick sound test using the instructions in that manual if you can. That will let you know if the board is bad, or just your wiring.

BTW, did the sound on this board work before? Have you been trying to do the stereo sound mod? Does the mono channel work? If you are using the mono channel, is the volume pot adjusted right?

Then I would go and double check you did the stereo mod correctly, and check for other obvious things that can sometimes go wrong too, like making sure the volume is up real loud on the PSOne screen, make sure you have the headphone pins crossed right, etc.

Finally, did you cut the right trace for the mix after the op-amp, and have you disconnected the primary amp? I don't know for sure, but I am pretty sure you have to do this to get stereo sound output.

Also, looking at your pictures of soldering job, I would say it looks OK except for one thing. Where you have soldered to the op-amp on the Neo Geo it looks a bit messy. Make sure you have no shorts anywhere, or even ones that look like the might be shorts, because it can happen. Also, clean your flux residue off, you would not believe the kinds of random problems I have run into that I later realized were the fault of corrosive fluxes which I didn't clean off.

arfink · Post by **arfink** » Sun Nov 09, 2008 1:57 pm

Looking again at your op-amp, what are those orange and brown wires for? Just wondering I realized I had never seen a stereo mod that used more than two wires off the main op-amp.

Check against these two pics. Picture one is where to get L and R for the audio (these are relative to ground)

http://www.benheck.com/Downloads/Stereo_on_MV-1C.jpg

The second pic is what traces you need to cut to un-mix the channels.

http://www.benheck.com/Downloads/Traces_To_Cut.jpg

Keep in mind it is also possible to remove the main amplifier chip and run the whole unit on just +5V. Also keep in mind that without the main amp in there you might need to build yourself another smaller amplifier, but probably not.