Stereo Output on Namco NA1/NA2

[sk8er000]

Hello,
I've found this service manual where is explained what the 2 dips switches on the motherboard do (not shown in photo), what's the connectors pinout and how to use stereo audio.

It's pretty clear (being able to read japanese) what it must be done but I don't get any sound from A2 and B2 pad after switching the jumper to stereo (and settings the headphone potentiometer to max)

Does anyone tried this thing?

Thank you

 

[Astro X]

Does anyone tried this thing?

yes, it works fine.........

 

[sk8er000]

yes, it works fine.........

Do you get audio from A2 and B2?

 

[Astro X]

ah, sorry.
I get it from A1 + B1 for right and 10 + L for left.............

 

[sk8er000]

In that case if I'm not wrong you're using amplified signal for the speakers and if not attenuated can damage the hifi

 

[Astro X]

i can check the A2 and B2 output next days.........

 

[hardyhell]

sorry to ask but where exactly are the points to get stereo?

left channel at the jamma and right channel off the board somewhere else?

 

[sk8er000]

A1 = Right Speaker(+)*
B1 = Right Speaker (-)*
A2 = Headphones Right Channel
B2 = Headphones Left Channel
B3 = Headphones Ground

Those are the connections on the 48 Pin connector near the jamma one.

*you have to pair that channel with the speaker pads on the jamma that will become the left channel. Be aware that you can't use those signals with a stereo, a regular tv or headphones without an attenuation circuit. The one you should use are the headphones out but at least for me they are not working, maybe I'm missing something.

 

[Astro X]

i can check the A2 and B2 output next days.........

done.
it works, depending on VR1........

 

[hardyhell]

A gosh. Wrong system. Never mind

 

[sk8er000]

done.
it works, depending on VR1........

I've set mine on both ends but there is no audio I'll have to check the impedance, did you used some resistor like on the scheme at the bottom or you connected 2 rca straight?

 

[Astro X]

connected 2 rca straight?

that.
check if you have connections at A2 + B2 on the PCB.
for example, there are none on the ND1 system at this point.........

 

[sk8er000]

ND1 lacks also the filter near the connector and don't have the double potentiometer, all NA1 and NA2 have the same components so if it's working for you it should work for me, I was asking if you connected RCAs/headphones without any other component or you've used the resistors suggested on the manual (scheme at the bottom of the page)

 

[Astro X]

i have connected RCAs/headphones without any other component.............