Hyper Neo Geo 64 - revision 1 pcb (Audio assistance)

[tengugurl]

Hi there!
I recently purchased a revision 1 fighting pcb and I have the pot on the front of the IO Board and the jst connectors for sound and powering the amp.

I am trying to get sound out of the board but the pin outs cia the manual are kinda hard to see…

looks like

power supply jst. Audio connector
[ 5v+ | 5v+ ] [ Too blurry | idk ]
[ GND | GND] [ Too blurry| Idk ]

if I didn’t pack all my stuff to move I’d be able to wip out my multimeter and see by process of elimination which is GND which is not but I figured I’d ask.

last question,
Could I make a jst daisy chain adapter off the psu or potentially even off the 5v+ jamma edge? (Just not sure how they had these wired up back in the day)

I eventually want to make an adapter that has a mono/stereo option like the image attached

thanks for your help

 

[nem]

It's on the following page of that manual:

1 SPK-
2 SPK+
3 SPK2-
4 SPK2+

(haven't personally verified this)

 

[tengugurl]

You are so right! Thanks
I was being too literal and saw that in the manual and was like “well that jst connection doesn’t look like that so I better ask”

appreciate it

 

[awbacon1]

don't forget you can mod the I/O board to get audio too

http://www.jamma-nation-x.com/jammax/tutorials.html

 

[mathewbeall]

So this is interesting, I have a Rev1 fighting mobo - and the sound works via the JAMMA edge, and the pot controls volume. I just got a NIB unit, and am looking to do the same mod, but wanted to pass it by the smart folks here on AP. According to the jamma-nation post above, you just remove a resistor and jumper two points, but then you have a single volume level. Here is a picture of the Rev1 I got that was modded (seems like two cap's removed, and two wires removed from the pot to those spots (4670). For reference - here is my pristine new Rev1 board. (4671).

Those pink and purple wires go up to the connector on the main board - pins 1 and 2.

Has anyone seen this done before?

 

[nem]

WTF

 

[mathewbeall]

I can tell you that it works on the board I already have where this mod was done! I will try and look for some schematics later today and see what circuit those two capacitors are in.

 

[mathewbeall]

So the wires aren't off the pot - they are just cut from the back of the speaker connector.

The pink wire (I assume that is pin 1, so SPKR -) is hooked up to negative pad of AC33 cap (normally a 1000uf cap)
the purple wire (I assume that is pin 4, so SPKR2 +) is hooked up to negative pad of AC35 cap (1000 uf cap)

With it hooked up this way, I get both left and right sounds (mixed) through the JAMMA edge in mono.

I wasn't able to find any sort of IO board circuit diagram to see what circuits these are for.

If this is a valid modification (and it does seem to work on my first board) - we should tell Jamma nation about it.

Matt

 

[mathewbeall]

I just performed this easy mod on my NOS HyperNeoGeo64 (remove 2 capacitors, tap into the wires on the front and solder one each to the negative pad of AC35 and AC33). This does indeed give you POT controlled audio out the JAMMA edge. When I go and do a sound test, I get sound for right/left/center.

Matt

 

[FrAshi]

Niiice gonna pick up a board now! Awesome work

 

[chacal231077]

Hi!

It would be nice to create a pluggable PCB to handle this exotic sound output like a real stereo output, without disfiguring or aesthetically modifying the motherboard with cables, removing capacitors, etc...

 

[awbacon1]

I just performed this easy mod on my NOS HyperNeoGeo64 (remove 2 capacitors, tap into the wires on the front and solder one each to the negative pad of AC35 and AC33). This does indeed give you POT controlled audio out the JAMMA edge. When I go and do a sound test, I get sound for right/left/center.

Matt

awesome to know!

 

[mathewbeall]

Hi!

It would be nice to create a pluggable PCB to handle this exotic sound output like a real stereo output, without disfiguring or aesthetically modifying the motherboard with cables, removing capacitors, etc...

I agree that it would be nice - but very easy to reverse this mod - remove two wires and solder back in 2 capacitors.

Matt

 

[GuileWinQuote]

I just performed this easy mod on my NOS HyperNeoGeo64 (remove 2 capacitors, tap into the wires on the front and solder one each to the negative pad of AC35 and AC33). This does indeed give you POT controlled audio out the JAMMA edge. When I go and do a sound test, I get sound for right/left/center.

Matt

Just did this and it worked, thanks!

 

[hans_stockmann]

Sorry for the bump but I don't see a need to make another HNG64 Rev 1 Audio thread for this question.

I bought one last week and my board already has a speaker cable set wired in. What's the name of this connector a previous owner's installed and are there adaptors so I can just easily plug it into RCA or something?

 

[cruzlink2]

Guys anyone knows the original value of the resistor that gets removed when doing a mono audio mod? I have a friend who did that mod long ago, I want to revest it to do this mod but no idea what the resistor value is for R69. Anyone wiht this board can test the value or me please?

 

[mathewbeall]

I just took a reading on mine - I am coming up with 2.2kohm

Matt

 

[cruzlink2]

thanks a bunch @mathewbeall . did you do the mod on this thread to yours?

 

[mathewbeall]

Yep - just he simple mod to get sound out the Jamma edge....

 

[MegaShock-76]

Wondering if removing AC33 and AC35 caps will have an adverse affect? Anyone? Also sent James @JNX a message. Maybe he can chime in. Definitely interested in modding my Rev1 with this mod.