Naomi 1 - cant turn speakers on in sound test

PCB problems and fixes
Post Reply
Hrvat9
Posts: 191
Joined: April 26th, 2017, 3:47 pm
Location: Canada
eBay: hrvaat

Naomi 1 - cant turn speakers on in sound test

Post by Hrvat9 »

Naomi 1

It turns on and plays fine but there is no sound. Im hooked up with the jamma rev a naomi i/o in my NAC. Does it not pull mono sound from that?
Also when i go to the test menu, in the sound test the left and right speaker are turned off. I can turn them on but as soon as i exit the sound menu and go back in theyre turned off again :/
candy: Sega New Astro City x2, Sega Versus City (sold)
Seeeegggggaaaaaa
User avatar
GeekMan1222
Please Continue...
Posts: 237
Joined: August 16th, 2014, 3:17 am
Location: SC, USA
eBay: geekman2005

Re: Naomi 1 - cant turn speakers on in sound test

Post by GeekMan1222 »

What I/O do you have? Have you tried with speakers outside the NAC? Do you have another cart to test with maybe somethings wrong with the cart your using?
1x New Astro City, 1x Madonna, 1x G-Balance
Hrvat9
Posts: 191
Joined: April 26th, 2017, 3:47 pm
Location: Canada
eBay: hrvaat

Re: Naomi 1 - cant turn speakers on in sound test

Post by Hrvat9 »

GeekMan1222 wrote:What I/O do you have? Have you tried with speakers outside the NAC? Do you have another cart to test with maybe somethings wrong with the cart your using?
The regualr sega naomi i/o board, rev a.
How do i do it with other speakers? I dont have an amp or anything , its connected straight to the jamma harness from the i/0. Doesnt that mean i should have mono sound?
I read somewhwre that theres a jumper i have to set from rca to mono, is this true?
candy: Sega New Astro City x2, Sega Versus City (sold)
Seeeegggggaaaaaa
User avatar
GeekMan1222
Please Continue...
Posts: 237
Joined: August 16th, 2014, 3:17 am
Location: SC, USA
eBay: geekman2005

Re: Naomi 1 - cant turn speakers on in sound test

Post by GeekMan1222 »

I wasnt aware of a jumper ill have to double check real quick. If you have any kind of powered speakers you can plug the rca output from the naomi into that to test. But im not sure if you said the test tones played fine or not?

I assume you have the Sega I/O with the built in sound amp then? Like this? http://i.ebayimg.com/images/g/-zoAAOSwN ... -l1600.jpg
If its like mine the 838-13683-93 then there is no sound amp and the only jumper on the board is Jp1 but thats for changing something with the kick harness feature iirc http://wiki.arcadeotaku.com/images/thum ... 93-pcb.jpg

I would assume you would have some sort of sound even if its not a stereo cabinet i could be wrong.
You do need an I/O with a sound amp or an external amp of some sort to boost the reference audio signal coming off the RCA connectors on your Naomi .
1x New Astro City, 1x Madonna, 1x G-Balance
Hrvat9
Posts: 191
Joined: April 26th, 2017, 3:47 pm
Location: Canada
eBay: hrvaat

Re: Naomi 1 - cant turn speakers on in sound test

Post by Hrvat9 »

I have the regular i/o that comes with naomi, same one as yours
This:
https://retrogamingstuff.files.wordpres ... -rev-b.jpg

No test tones play at all. The test menu says right and left speakers are off and then in the game settings sound test no music can be heard

So through the jamma i cant get sound on a naomi?
candy: Sega New Astro City x2, Sega Versus City (sold)
Seeeegggggaaaaaa
User avatar
GeekMan1222
Please Continue...
Posts: 237
Joined: August 16th, 2014, 3:17 am
Location: SC, USA
eBay: geekman2005

Re: Naomi 1 - cant turn speakers on in sound test

Post by GeekMan1222 »

Ah ok, yes. What you will need is some sort of Audio Amplifier to connect between your Naomi and your speakers in your cabinet. The I/O its self will only handle controls not sound.

You can buy a sound amp of some sort and splice it in some how with the speaker wires or find an official Naomi Sound amp.

I have not done this mod my self yet (i just used external pc speakers.) so Im sure other members have better advice on this issue.

You could get something like this, https://www.amazon.com/Pyle-PFA300-90-W ... =sound+amp
1x New Astro City, 1x Madonna, 1x G-Balance
User avatar
NoAffinity
Posts: 386
Joined: January 8th, 2017, 3:46 pm
Location: Escondido, CA, USA
eBay: noaffinity
Initials: CSG
Contact:

Re: Naomi 1 - cant turn speakers on in sound test

Post by NoAffinity »

Another budget option for an amp: https://www.parts-express.com/kinter-ma ... mpaign=pla

There are plenty of budget options out there, including bare PCB. Don't know the wattage of the speakers in your cab are, but most of mine are 4-8w @ 8 ohm, so something like this is more than sufficient.
User avatar
outrun2
Posts: 253
Joined: August 18th, 2010, 6:25 pm
Location: Gloucestershire, UK
eBay: thefonzzz
Initials: GAZ

Re: Naomi 1 - cant turn speakers on in sound test

Post by outrun2 »

I can't really help with your problem.. but I know you won't get any sound if the volume pots are not wired up properly (on a standard jvs setup anyway) .

I do have a spare Naomi amp if you need one.
Wanted:
Sega Model 3 Emergency Call Ambulance ROM board or complete Step 2 boardset.
User avatar
GeekMan1222
Please Continue...
Posts: 237
Joined: August 16th, 2014, 3:17 am
Location: SC, USA
eBay: geekman2005

Re: Naomi 1 - cant turn speakers on in sound test

Post by GeekMan1222 »

Edit: Nvm. I answered my own question actually lol

That being said, http://wiki.arcadeotaku.com/w/Astro_City_Stereo_Wiring has really useful info and I plan on doing it my self. 8-)
1x New Astro City, 1x Madonna, 1x G-Balance
Post Reply