Crackling/scratchy audio. Not sure if cart(s) or Omega CMVS

[cr4zymanz0r]

I have a handful of MVS carts, but I've noticed some scratchy sound on 2 games. (might need to try some of my other games in depth to see if it happens on them too periodically)

A week or two ago I booted up Last Blade 2, and there was scratchy audio in the intro. The very beginning with piano only sounded fine, but immediately after that it got scratchy. At the time I just took the cart out and reinserted it, then all was good. I assumed it was just one of those every-once-in-a-while connection issues.

Well, I just got in Shock Troopers yesterday and I'm having a ton of issues with it. Here's a video of what it typically sounds like on most attempts:

Now it doesn't happen EVERY time, just most times and I can never get it to play perfectly. It acts like in the video most of the time, but sometimes If I'm lucky on crossing my fingers just right when inserting the cart, everything will start out fine but eventually revert back to the kind of sound you hear in the video. So far the best I've done is make it to the 3rd level before it starts acting up again.

After encountering this, I tried Last Blade 2 again and it does occasionally have the same sounding issue on the intro (didn't play past the intro), but reinserting the cart has fixed it everytime. Also, Last Blade 2 works fine the majority of the time on the first try so it's far less annoying than Shock Troopers, which I can't seem to get 100% good sound for the duration of a playthrough.

Any thoughts? I'd like to be able to isolate this so I don't go barking up the wrong tree when trying to get whatever is at fault fixed/replaced.

EDIT: Both carts pass the CRC check in Unibios

 

[Apocalypse]

Seems like a loose contact on the cartridge connector.

 

[ChuChu Flamingo]

I know this will sound dumb but have you cleaned both your mvs pin connector and cartridge connector?

 

[cr4zymanz0r]

I know this will sound dumb but have you cleaned both your mvs pin connector and cartridge connector?

All my carts have been cleaned until the pins are nice and shiny. Haven't cleaned the Omega CMVS cartridge slots, but I've only had it a month and only use clean carts in it. I don't get any additional dirt/grime off the cart pins after using it in the Omega either. I could probably take the cleaning tab out of my NES cleaning kit and use it. Is there a particular pin or set of pins for me to pay special attention to for this issue?

 

[shadowkn55]

All my carts have been cleaned until the pins are nice and shiny. Haven't cleaned the Omega CMVS cartridge slots, but I've only had it a month and only use clean carts in it. I don't get any additional dirt/grime off the cart pins after using it in the Omega either. I could probably take the cleaning tab out of my NES cleaning kit and use it. Is there a particular pin or set of pins for me to pay special attention to for this issue?

The right side of both cartridge connectors are audio related.

 

[cr4zymanz0r]

Cleaned the cartridge slots, didn't really get any dirt/grime from cleaning. Performance seems to be roughly the same.
Possibly coincidence, but since the right side is audio related, I ever so slightly pulled up the right side of Shock Troopers after inserting it and it took longer for the audio issue to pop up again (level 3).
I've looked in the cartridge slots with a flashlight and can't see anything obviously wrong such as corrosion or bent pins.

One thing I've noticed is when I insert Last Blade 2 it feels like it fits more snug, as if maybe the PCBs are slightly thicker. It works fine the majority of time.
Shock Troopers seems to glide in with more easy. It doesn't feel super loose going in, just not as snug as Last Blade 2.

At this point I don't know what to do other than open the Omega up to see if there's any broken solder joints or something on the cartridge slots. I don't really want to open it though without shadowkn55's 'permission' though for fear of possibly voiding whatever kind of warranty It might have on it. I'm a technical guy that can check connections with a multimeter, do most soldering that isn't super fine pitch (tiny surface mount stuff), etc. but I'm just not super knowledgeable about Neo technical details since I haven't really worked on one before.

Shock Troopers is by far the biggest pain since, although it varies, it ends up having some issue on every single play attempt. Having to reinsert Last Blade once every 5 or so inserts isn't terribly a huge deal on it's own. Shock Troopers pins look clean after cleaning with rubbing alcohol and a white eraser. Maybe I need to get some Brasso to use to make them extra clean and shiny?

 

[shadowkn55]

Do all your games do this? Or is it just particular to these two?

 

[cr4zymanz0r]

Just these 2 it seems, though oddly enough I use to play Last Blade 2 on a Daedalus MVS to AES converter and never heard scratchy sound on it (don't have the converter anymore). I haven't played my other games dozens of times or anything, but I've never heard a sound issue out of them in the Omega.

 

[shadowkn55]

Just these 2 it seems, though oddly enough I use to play Last Blade 2 on a Daedalus MVS to AES converter and never heard scratchy sound on it (don't have the converter anymore). I haven't played my other games dozens of times or anything, but I've never heard a sound issue out of them in the Omega.

If it's just these two, it's probably a cracked solder joint or a bad pcm chip. Can you post pics of the front and back of all the boards?

 

[wyndcrosser]

I had a similar issue and it was my YM chip on my AES. Some pins where not showing continuity. It happened during explosions etc.

Edit, have you tried other TVs?

 

[cr4zymanz0r]

If it's just these two, it's probably a cracked solder joint or a bad pcm chip. Can you post pics of the front and back of all the boards?

Here's a link to pics of my Shock Troopers boards: http://imgur.com/a/du8FK

I had a similar issue and it was my YM chip on my AES. Some pins where not showing continuity. It happened during explosions etc.

Edit, have you tried other TVs?

Actually, I haven't tried another TV yet but my dozen or so other systems hooked to the TV don't have any sound issues :P

 

[shadowkn55]

A few of the pins on M1 look suspect. Trying reflowing pins 13,14,15,16,17,18,19,20.

 

[cr4zymanz0r]

A few of the pins on M1 look suspect. Trying reflowing pins 13,14,15,16,17,18,19,20.

Well, it appears to be (mostly) fixed now so far, though I'm not 100% sure which thing fixed it. When I had the boards out to take pictures I also cleaned the pins with Brasso afterwards. Pins didn't look too different to me afterwards, but the q-tips sure looked dirty. By the time was done with that, I saw your suggestion on reflowing the pins so I did that as well.

I put it back together, let it run attract mode for a good bit while I did some things around the house. Came back and it still sounded fine.
Reinserted the cart for good measure to make sure it wasn't coincidence, played and got to the last level (or maybe next to last) before I ran out of continues, still no sound issue.
Reinserted again, fired up the game again for a few minutes, still no issue.

Everything seemed good initially, but there's at least one remaining issue that I discovered. I was playing the mountain route and got to the snowy stage. It seems the first few seconds of the song is nearly silent.
Here's what the song sounds like normally:

The song is also nearly silent when played through the Unibios jukebox, So I recorded from there. It doesn't start until about 12sec in. Now I don't think my recording picked it up, but in the "silent" initial 12 sec there's some mild 'pops' in a beat (same sound each time). Here's me playing on mine. The volume might have to be turned up.

The song was also silent the first few sec before doing any of this work because I was listening to the songs on the Unibios jukebox and found it odd that song had what i thought was a delay.

 

[Xian Xi]

Check the two traces by the big hole on the right which run to the M1. Make sure they aren't broken.

 

[GadgetUK]

As Xian Xi says - look at the hole cut outs on the board with the M1 - on that photo there are traces with copper exposed there right next to the hole. Maybe a damaged connection?

 

[cr4zymanz0r]

Checked continuity on those 2 traces and it was fine. I've even reflowed and added a little bit of new solder to all the pins on M1, but no change.

 

[Xian Xi]

Check continuity from the cart edge on the back of the PROG board. Looks like some retard used sandpaper on the contacts. When people do that it's every easy to cut a trace enough to disconnect it and it will look fine.

 

[cr4zymanz0r]

Check continuity from the cart edge on the back of the PROG board. Looks like some retard used sandpaper on the contacts. When people do that it's every easy to cut a trace enough to disconnect it and it will look fine.

Yay, fixed! Checked all the edge pins on the back like you said, but continuity was fine. Decided to check front edge pins as well while I had it out, even though the front looked fine to the naked eye. Well, I found one pin with no continuity. 10th pin from the left (if counting the 1st fat pin as a singular pin). Looked fine to the naked eye, but no connection. Used a tiny bit of solder spread thinly to reconnect, continuity tested good, tried the game, song worked fine then! I was always under the impression that cut/damaged traces were more visually obvious than this.

Funnily enough, there were other smaller details in other songs that were missing as well before this was fixed. I'd just never played Shock Troopers until I got this cart in last week, so I didn't know the songs by memory to know the others sounded off since it was smaller details missing. It was annoying since it was sold (not on these forums) as working with no issues mentioned, but the repair probably ended up being easier than returning it to another country.

Thanks for your help everyone. It does feel good to repair something worthwhile rather than assuming it's junk and tossing it (or returning it, to where it'd probably also be tossed)