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TMNT 1989 Board Muffled sound in JAMMA cab

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shadowblind

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Hello!

Some years ago I got a 4player TMNT board but never had a cab to test it in. Now, I plugged it up to my one-slot Neo Geo cab running a JAMMA harness and it mostly works for testing player 1 and 2...except the sound is so low. Only if I press my ear against the speaker can I hear it just barely. Anyone know the cause/fix for this? I read that it's Amplified Mono just like the Neo Geo 1 slot, so I thought it would work plug-and-play, albeit without players 3 and 4. Still very new to the tech side of the hobby so any help is appreciated.
 
Have you tried adjusting the volume knob on the tmnt board?
 
Is your Neo a stereo one slot, and are its speakers wired for stereo?
 
Looks like its speakers are wired for mono. As well, my other mono boards (like Risky Challenge) sound good in the cab. There's also no amp in the cab. Also tested in my Captain America and the Avengers cab and couldn't get sound the TMNT board to have sound there either...

...which i think confirms mono? Please correct me if I'm wrong haha.

EDIT: I think I'm wrong, actually. The cap cab seems to actually be running stereo since it uses a four pin connector on the board itself rather than through JAMMA. Now I'm questioning myself about the Neo Geo, too. Gonna run a test and see. A little surprised, since I was told that Risky Challenge can only work in Mono...

EDIT 2: Okay so the Cap cab is stereo and gets its audio through a different cable than Jamma. But my neo geo for sure gets its audio through the JAMMA harness. Changing the motherboard from stereo to mono and back makes no change, so I think it's mono?
 
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For true jamma you need the proper wiring. I think you may have a series wired speaker set.
One speaker, wires to speaker+ and speaker-

Kujako

Thread 'Confusion over MVS cabinets speaker wiring. "parallel" vs "series"'

Looking at adding a JAMMA board to my MVS-25-2 cabinet. There are a few adapter boards out there, but one thing that caught my eye was the JNX Big Red adapter which carries the warning "If your cabinet's audio wiring is setup as parallel, then this adapter will not work for you. It is meant for original MVS multi slot cabinets that have their speakers wired in series. Using this adapter in a parallel wired cabinet can damage the audio amp on the JAMMA board". This is causing me some confusion, as I didn't think the audio wiring was either parallel or series but distinct with...
 
Quick question, I have to add wires into my Captain America and the Avengers JAMMA harness for speaker wires (to hook them up only when I have TMNT in it) and it appears the harness uses Molex crimp terminals. But I can't figure out exactly which size to get! Anyone that might know? .156 seems to be standard but there are so many sizes I'm not sure which one's right.
 
I wondered if that's what it could be! I need to test on a mono cab to be sure, but if that doesn't work, then the caps going out makes the most sense.
 
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