Ehrgeiz PCB with Intermittent Sound

Blur2040

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I have an Ehrgeiz PCB with intermittent sound off the Jamma edge.

The sound is always find through the line level RCA outputs on the board, but Jamma Edge sound only works some of the time. On occasion you'll boot it up and it will work fine. Most of the time, no love.

Weird, likely related issue: Today i took it out to play, sound worked just fine. Played through 3 or 4 matches in single player mode and then suddenly, the game board reset and there was no sound. This makes me think it might be a power issue...but other system 12 game (soul calibur) seems to be AOK...so I'm inclined against that.

Thoughts?
 
If the sound is always good through RCA but not JAMMA then check the cab wiring and the volume control. After that recap the audio amplifier section of the game board...
 
since the RCAs are line level, they won't require +12 to operate right? only the amplified portion that feeds through JAMMA should.

I would also check out your power supply, make sure it's not on the fritz, especially if it's an older unit. reset would be symptomatic of a low +5, which I think would cause +12 to go high, but that could be low too. need to brush up on my switching mode power supply operations.

check both. if your +12 is substantially low, then I'd say you've found your cause. if it's ok, then do what channelmanic suggests. make sure your +5 is about 5.15, unless you can find a good spot to meter +5 at a component... I'm not sure on one of those boards.
 
mecha187 said:
since the RCAs are line level, they won't require +12 to operate right? only the amplified portion that feeds through JAMMA should.
Not necessarily, the audio still needs to be amplified to become line level.
 
Just for some clarifications:

I'm on a Supergun, so fewer spots where the wiring can go on. I suppose I can double check my jamma pins, though, to make sure they're getting good contact. As the setup works fine with other games, thats the only spot where I guess there could be a major issue.

Further, I think the symptom that the sound working, then resetting, then no sound is likely suggestive of something perhaps a bit more serious.

I'll be checking the power supply on it this evening, but I don't suspect much issue as its only a few months old. I had the same issue on another PS as well. But low power could be the issue I suppose.

Thanks for the suggestions thus far. I'll report back when I get the chance to take a look.
 
Further, I think the symptom that the sound working, then resetting, then no sound is likely suggestive of something perhaps a bit more serious.

You mentioned that the RCA levels are fine. If the sound never does this through the line level outputs then the digital parts of the sound circuitry are OK and the amplifier section is suspect.
 
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