Cyber-Lip MVS corrupt sound

[K1ngArth3r]

I need to some help and advice on how to fix my Cyber-Lip MVS board.

The fault is the sound is completely messed up, I have filmed a video so you can hear it. Some of the sounds appear okay, were as other sounds are messed up.

I don't want do start desoldering chips randomly and comparing the data to MAME, so wanted a bit of a guide to pin point potential faulty chips to target first.

Its an original board as verified on MVS-Scans and as far as I can see, it's not had any repairs previously done to it. (Although an owner in the past has appeared to have used brasso or similar to remove most of the gold coating from the pins.

I have checked continuity between the pins and the via and they are all good. I cannot see any cold solder joints or broken traces, so I imagine it's going to be one the chips.

I did a little bit of research and similar issues point to the custom PCM chip being the cause of the issue, this doesn't appear to have one so it's not that.

 

[Neo Alec]

Check the traces and solder joints on the V (sound sample) roms.

 

[K1ngArth3r]

Okay, I will do that this evening thanks.

 

[K1ngArth3r]

I checked the CHA-32 board using this schematic and couldn't find any trace issues or issues with the solder joints, however I'm going to reflow all the points to be on the safe side.

It seems that all (most) of the sounds are fine except for the actual music, which should narrow it down to which sound sample rom I need to focus on. Do you, or anyone else know which mask ROM handles the background music?

 

[ack]

The V roms are on the PROG board

 

[K1ngArth3r]

Ah yes, I got them the wrong way round. CHA for Character sprites and PROG for the Audio. Thanks, I will start the checks from scratch now and report back.

 

[K1ngArth3r]

Okay, I'm confident that all the traces are okay and there is no solder issues on the PROG-EP board either.

I went into the Jukebox mode of the UNI-BIOS and it seems that all the stage music is corrupted but the sound samples seems pretty clear.

Short of probing each of the V ROMS (which I cannot do here as I don't have the setup), is there a way to narrow down which mask ROM(s) is corrupted based on experience?

If not the only choice I have as I see it is remove each mask ROM and compare it to the ones in MAME (which sounds like a real long winded job to desolder all of those tiny solder points).

 

[ack]

I haven't done this before, but in theory you could corrupt each V rom in mame one at a time and see which one mimics what you are hearing.

 

[K1ngArth3r]

Im going to look into that as it seems the easiest route for me. I've also PM'd GadgetUK to see if he has time to look at it since he's got all the gear.

 

[Xian Xi]

With the older games pre-Neo PCM, a lot of times the sound gets messed up because of a bad LS174 way more often than a bad rom.

 

[K1ngArth3r]

Thanks for the heads up. I guess that pretty much means it could be 90% of the chips on the PROG board (when considering both EPROMS and LS174 chips). I will try and get someone with all the equipment to look at it for me and report back with what the fault was.

 

[K1ngArth3r]

Just an update, it turns out 3 of the 5 V ROMS were bad!

GadgetUK repaired this for me and now it's running well.
I believe he will be releasing a video on it in the near future. Thanks to everyone who tried to help me.

 

[Hawwa]

Great! Link here the video when he uploads it, I'd like to see it.

 

[Neo Alec]

How does that happen? Must have been stored improperly? Anyway, congratulations getting it fixed. Gadget UK does great work.

 

[K1ngArth3r]

How does that happen? Must have been stored improperly? Anyway, congratulations getting it fixed. Gadget UK does great work.

I have no idea. I bought the game from eBay not realising that it was broken (My fault). The seller said that he had sold it working to some guy in Austria who had it for about 1 month and then returned it when all of a sudden the game developed a sound issue.

The game was sold in a box which got chewed up during the ordeal. My intuition tells me it was mistreated somehow, either stored badly or maybe some weird issue with voltage (I'm speculating of course).

 

[K1ngArth3r]

Double post

 

[K1ngArth3r]