Strange music dropouts on consolized MVS

[NeoNovice]

I recently got a consolized MVS from Timeharvest, and it’s having some odd sound issues, but only with certain games.

Usually just the music will die and the sound effects remain. Sometimes all sound dies, with the music holding a single sustained tone. World Heroes 2 and Magician Lord are chronic offenders.

But other games are flawless and have no issues at all, so I figure it can’t be the capacitors (plus it was recapped). Something to do with FM sound vs. PCM, maybe? I don’t have many games, but Art of Fighting and Cyber Lip work perfectly. UNLESS I use them right after one of the offender carts. Clearing the backup memory seems to restore the good carts, but never helps the bad ones.

What on earth is going on here? I used deoxit thoroughly on the cart slot and carts, with no change.

 

[XianXi]

Sounds like a spotty connection from the cart slot to the YSA2. Some games use different traces for sound so if it's happening with only a handful of games, then it's a trace the other games aren't using.

 

[pierpa86]

If that happen only on certain game and game not change, are the same.
If you lose channel, can be the PCM chip on game pcb.
First thing get a fiber pen https://www.amazon.it/Penna-Abrasiva-Fibra-4-Mm/dp/B002Z8IX36/ref=sr_1_2?sr=8-2 and clean the game contacts.
I got the same problem on converted superside kik, solved replacing the pcm chip.
You can take 1 game card and check also the crc of M1 and V1+V2 ecc.. eeprom but its take some time and practice.
if you need a new pcm chip https://www.tindie.com/products/furrtek/pcm-chip-replacement/
or buy a cheap game and take it off

if the problem is on mvs cart slot you will get the audio error also on CyberLip becouse this game works in the same way as MagianLord.
On this game you dont have PCM Chip but instead you have some LS174 and other logic chip that can be desolder and tested, much easier than changing the PCM chip.

All the other new game work in a different way.

( or sell it broken to me so i can fix )


1- Take 1 game with the problem, test it with a different MVS board
2- After you are sure that the problem is on the game open it
3- Clean the contacts with fiber pen
4- desolder all PROG eeprom and check the crc with google and rom file
5- if all are good, desolder the LS174 and test it. (only pre pcm game cart)
5.1- get a new pcm chip or get a donor cart and move all the eeprom tested. (be sure of what you are doing, you cant do it with all game but almost)

You can solve it