What's new
By:

MV1B audio help, left channel lower volume

R

rcboosted

Enthusiast
Joined
Jan 17, 2021
Messages
207
Reaction score
93
Location
Los Angeles
So my MV1B finally arrived and everything seems to be working properly. Audio is low and the trimmer pot for volume is scratchy, but since I will be modding it for stereo, I didn't mind it. I'm using an ebay Supergun by this seller neojamma that RGB Bob mentioned in his blog. I also got his stereo mod kit. Everything hooked up easily but my left channel is 10dBA lower when tested with a sound level meter. (it's obvious to the ear, I just wanted to quantify it) For the 5V mod, I didn't cut the trace, I simply lifted the pin on the chip and soldered the wire to the leg. Anyone know how I can troubleshoot this or if this is something that is known? Are there caps that could be going bad that might need to be replaced? The caps looks old, but not leaking or bulging. Attached is a pic of my mod.

I also came across this post on a different forum that taps into YM3016-D DAC chip directly. Has anyone tried this?
https://16bitgamer.canadian-forum.com/t152-neo-geo-mv-1b-stereo-line-out-mod

based on the spec sheet though, the pins indicated are the wrong ones, they should be in the same position in the other row. If we tap directly into the DAC, would we not need the stereo mod kit to attenuate the audio anymore?
 

Attachments

  • IMG_20210225_215517047_HDR.jpg
    IMG_20210225_215517047_HDR.jpg
    195.3 KB · Views: 225
So reading up on some threads on low volumes, some people replaced the capacitors and it fixed the issue for them, so I recapped mine. It didn't fix anything, the sound is still lower on the left channel. At least everything still worked and I was playing Puzzle Bobble 2 on the 161 in 1 cart. 10 min into the game, the sound disappeared, I got no sound at all on any game now. What did I break? :) i only have the 161 cart right now, so I can't test with an original cart.
 
Last edited:
rcboosted, I was planning to install one of these stereo kits.
I was curious how you hooked your Right and Left cables to your speakers.
Did you run it to a 2.5mm stereo plug? If so, where did you pull a ground from?
 
Last edited:
The output from the kit has L and R, those go to the positives for each channel. - you just tie to ground for both channels, any ground from the board will work.

As for my original issue, it was a bad Z80.
 
You must log in or register to reply here.
Back
Top