Jamma Sound/Speaker issue

Phetishboy

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I am hooking up my jrok board into my Joust machine via a jamma harness. Got the video looking great, controls seem to work, but I can't get sound? I have the speaker + and - hooked up to the correct terminals on the speaker, but nothing. No sound, no pops, nothing. I tested my jrok board in another jamma cab, sound works great there. Pull it back out and try it in this cab again, no sound. Try a different speaker, still nothing. What's up? Bad harness? (It's new)
 
I assume the speaker is hooked up to pins L & 10 on the jamma harness,so I would check the connections on those wires for maybe a bad crimp or solder.
That is how my Jrok is wired in my Joust cab.
 
I assume the speaker is hooked up to pins L & 10 on the jamma harness,so I would check the connections on those wires for maybe a bad crimp or solder.
That is how my Jrok is wired in my Joust cab.

That's just it, the wires go straight from the edge connector to the speaker terminals. The distance is no more than 4 feet. There are no crimps, solder, butt connectors, nothing between the edge connector and the speaker. L & 10 are the + and -, and those are the wires that are hooked up directly to the speaker. Just for fun, I tried to hook up the Audio wires to the speaker. Nothing. This has to be something simple.
 
Did you check the connections at the edge connector?
Maybe one of the wires is not making contact.
I was thinking maybe there is a broken connection at the edge connector.
It has to be a wire or edge connector issue since the pcb works in a different cab.
 
Try the speaker in another cabinet? Maybe try another board besides the jrok in the problem cabinet?

He tried another speaker.
Another board would be a good idea,though the Jrok works in another cab.
That would confirm the problem is in the harness.
 
Try a different speaker, still nothing. What's up? Bad harness? (It's new)

A really funky thing I came across not that long ago was a crimp spade connectors for a speaker where the barrel has been crimped only to the insulator of the wire (!)
It looked like a really nice job until you looked closely at the connector and could see the wire didn't actually make contact with the metal of the connector ;)

Do an resistance test across the speaker pins on the JAMMA harness, you should see 4 to 8 ohms or so. That would tell it's open circuit.

- James
 
A really funky thing I came across not that long ago was a crimp spade connectors for a speaker where the barrel has been crimped only to the insulator of the wire (!)
It looked like a really nice job until you looked closely at the connector and could see the wire didn't actually make contact with the metal of the connector ;)

Do an resistance test across the speaker pins on the JAMMA harness, you should see 4 to 8 ohms or so. That would tell it's open circuit.

- James

Yeah I've seen that too. In this case, the braided wire of the speaker output wires from the edge connector are directly in contact with the + and - tabs of the test speaker. So it goes

edge connector pins L & 10 ----> Speaker + and - tabs. The only thing that it could be is that the pins inside the edge connector of JUST the speaker outputs aren't making contact with the fingers on the board. The power, controls, video, service, etc all work. Just no sound output at all.
 
BTW, what voltage powers the sound on this board? According to what I remember from the pinout schematics for the MW, you don't have to hook up the -5V or +12v from the switcher? Did I read that right? Cuz I have all voltages connected to the switcher out of habit. Would that be a problem?
 
I had similar problem recently and it turnout to be speaker - tied to the ground wire in the Jamma harness. this seems to cause a sound problem on certain boards.
 
BTW, what voltage powers the sound on this board? According to what I remember from the pinout schematics for the MW, you don't have to hook up the -5V or +12v from the switcher? Did I read that right? Cuz I have all voltages connected to the switcher out of habit. Would that be a problem?

It needs 5v only.

- James
 
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