MV1FZS - no sound.. but sound?

HornheaDD

Viewpoint Vigilante
Fagit of the Year
Joined
Mar 22, 2016
Posts
4,273
So I bought an MV1FZS from ol Bill Burgerbutt recently. He said it had no video. It was $40 so I figured what the hey, maybe I can learn a thing or two about fixin' Neos. I got it today and it does indeed have video.

But it has no sound. Here's what I know so far:

The volume pot will make a difference in what I 'hear'. Its just your standard speaker hiss, but it WILL change the volume if the pot is turned up or down.
Tried a JPN BIOS, as well as an older UniBIOS I have layin around (still got my old purchased one from Raz :)) and they did not make a difference. I dunno if that was to be expected, but it wouldn't hurt to try, right?
Going into the hardware test menu via dip switches, I was able to test the speakers, and I successfully heard the little "ooo" tone from the left, right and stereo selections. Doesn't that right there tell us that the board has working sound?

A cursory examination of the board shows that it's pretty damn clean for being ancient, and it doesn't look like any parts are broken. I tried it with an actual Neo cart, as well as the other Banana cart I have, and still nuffin.

Any ideas as to what might be the cause of this?
 

HornheaDD

Viewpoint Vigilante
Fagit of the Year
Joined
Mar 22, 2016
Posts
4,273
Im not certain, I don't have a logic probe :/

I went ahead and bought a logic probe from Amazon, it was $20, so I figured why not.
 
Last edited:

HornheaDD

Viewpoint Vigilante
Fagit of the Year
Joined
Mar 22, 2016
Posts
4,273
is the digital audio okay?
OK! My super ultra maxi top of the line $20 logic probe came in, and it seems the digital audio is fine! Its producing that little static sound.

Some guys on Arcade Projects said it might be a trace as well. Gonna post this update there.

Thanks for the tip maki!
 

HornheaDD

Viewpoint Vigilante
Fagit of the Year
Joined
Mar 22, 2016
Posts
4,273
So I blew up this board. :(

After some research it looks like the sound chip is a common point of failure. So I ordered a new one for $9 to install it. I'm not a solderer, I wouldn't even consider myself an amateur solderer.

I was able to remove the chip using a hot air station and it worked great. Cleaned up the remaining solder with some wick and flux - but trying to get the solder out of the pin holes, even with an electric solder sucker proved difficult. I got like 15 of them cleaned out super pretty. But I guess while doing one of them I nicked a trace. And it's way too small for me to repair.

Oh well, at least this board was only $40.
 

Neo Alec

Ned's Ninja Academy Dropout
20 Year Member
Joined
Dec 7, 2000
Posts
11,925
Sounds very fixable for someone more experienced.
 

maki

Edo Express Delivery Guy
Joined
Jan 1, 2022
Posts
332
I'm not a solderer, I wouldn't even consider myself an amateur solderer.

I was able to remove the chip using a hot air station and it worked great.
You've used tools that are quite dangerous in inexperienced hands.

It does sound very fixable though (unless you did real damage with the hot air station, delaminating the PCB) , however if you want to practice the craft, start practice kits and/or old junk PCBs.
 

HornheaDD

Viewpoint Vigilante
Fagit of the Year
Joined
Mar 22, 2016
Posts
4,273
You've used tools that are quite dangerous in inexperienced hands.

It does sound very fixable though (unless you did real damage with the hot air station, delaminating the PCB) , however if you want to practice the craft, start practice kits and/or old junk PCBs.
I don't believe there was any delamination. I watched some vids and tutorials on how to use a hot air station to keep the heat even, not concentrating on one spot, etc. So that worked ok. I think the tool that did the damage is the desoldering gun. Its not a gun, but more like a large solder sucker, that has its own suction, you hit a button and 'ka-chunk!' it sucks in the solder, and if you let go it blows out, sometimes spitting solder out.

When I used it on a dead pc motherboard to try it, I realized the spitting thing so I made sure not to let go on the MVS board. But I think the 'ka-chunk!' which quite literally jolts the device in your hands is likely the culprit (beyond my own inexperience). So it kinda 'knocks' the board when using it. And Im fairly certain this caused some of the resin on the board to rub off and then nicked the trace.

You and Alec are not the first to say its likely fixable by an experienced solderer, so I'm looking into it and I might have a friend try and fix it for me. But if not, like I mentioned it was $40 and meant as a project so Im not too bummed that I blew it up. Im just bummed that I wasn't able to fix it myself.

edit: its this desoldering gun: Amazon Link
 

Neo Alec

Ned's Ninja Academy Dropout
20 Year Member
Joined
Dec 7, 2000
Posts
11,925
I use an old can to spit solder into. You need a safe place to release the sucked up solder.
 

maki

Edo Express Delivery Guy
Joined
Jan 1, 2022
Posts
332
When I used it on a dead pc motherboard to try it, I realized the spitting thing so I made sure not to let go on the MVS board. But I think the 'ka-chunk!' which quite literally jolts the device in your hands is likely the culprit (beyond my own inexperience). So it kinda 'knocks' the board when using it. And Im fairly certain this caused some of the resin on the board to rub off and then nicked the trace.
Yeah the recoil can hit the PCB and take away traces, especially when they're hot.

I use a manual desolder pump with a flexible silicon tube instead of the hard plastic/teflon tip on sensitive PCBs (Engineer SS-02).

I does sound like its fixable tbh, broken traces are very common for AES/MVS, good luck :)
 
Top