mvs 2 slot help

SavePointVG

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Not sure if there is another site for MVS stuff, but I am having some sound issues with my MVSF2. Did a little reading and learned that the caps go bad on these often because of ventiliation issues. Ive replaced the caps but still dont seem to get any sound coming from my speakers. When I go into the hardware test I still get nothing from the speakers. Just curious if anyone had any pointers. Thanks gang!
 
Did you replace the right caps? There are some 470uf caps that aren't in the kit and don't get replaced. If you replaced the wrong ones by the edge connector then you'll have no sound as those are commonly bad.
 
First things first... either take the carts out or flip DIP switch 1 and go into hardware test mode. Press P1 Start until you get to the audio test screen and test the audio outputs. Do you get audio? If so, your audio is working and you need to clean the slots/carts as the Z80 may be crashing because of poor contacts to the sound program ROM.

After that, reset the Backup RAM (part of the hardware tests), reboot the game (or power cycle it), and check again to see if you have audio during the hardware tests now... and if so, if you have audio during the game. Sometimes when the Backup RAM gets corrupt, the audio will disappear.

Next, touch the pins on the amplifier chip when it is on. Do you hear humming sounds when you do that? If so, the amp chip and the caps on the output will be working.

Now it gets more complex...

Do you have a logic probe? Does it have audio capabilities? If it does, you're in luck. Probe the YM3016 DAC chip and you'll hear the beeps change on the inputs to it when the audio is supposed to be playing. If you hear that, then the digital part of the circuitry is working.

If you don't, do you have an oscilloscope? If you do, you can check the inputs to the DAC chip with that.

If not, you're left with randomly swapping out parts until you figure out what was wrong with it.
 
You certainly laid it out for me, that's awesome. Ill get to work and let you know what I find out. At this point there is still no sound in test mode, even after the ram reset so it looks like Ill be digging a little deeper. Thanks for your input
 
You're welcome.

Sometimes you'll find a broken volume slider... or a cap was installed backwards, but that's usually not the cause.

If you couldn't tell, I repair a LOT of Neo Geo boards. ;)
 
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