MVS 4 slot board sound dying... need to replace caps

Spike Spiegel

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Can someone here help me out and tell me which cap or caps I need to replace on a 4 slot. The sound is pretty quiet, and I've done some research on here... I've found when the caps on the board start to go for sound, things get quiet. Mine has all the classic symptons. Sound comes out of left, but is fainter than right... quiet, but gets a hair louder if you leave it on for a while. I just don't know what to replace, and the part numbers.

Can someone help me out please? Maybe a picture of the board's caps so I know what to remove?
 

chris1

POCKETBIKE NUT,
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Spike Spiegel said:
Can someone here help me out and tell me which cap or caps I need to replace on a 4 slot. The sound is pretty quiet, and I've done some research on here... I've found when the caps on the board start to go for sound, things get quiet. Mine has all the classic symptons. Sound comes out of left, but is fainter than right... quiet, but gets a hair louder if you leave it on for a while. I just don't know what to replace, and the part numbers.

Can someone help me out please? Maybe a picture of the board's caps so I know what to remove?

Have you tried the board in another cab?(from reading your thread in general dis)

My 4 slot sounded that way in my Candy cab..until I found out that the wiring to the harness wasn't right..What it really consisted of was one of the ground wires into the harness wasn't in the right place.

Right now after changing that the 4 slots sound is normal..I though the board was bad,,(at first-until I tried it in my big red.
 

Spike Spiegel

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chris1 said:
Have you tried the board in another cab?(from reading your thread in general dis)

My 4 slot sounded that way in my Candy cab..until I found out that the wiring to the harness wasn't right..What it really consisted of was one of the ground wires into the harness wasn't in the right place.

Right now after changing that the 4 slots sound is normal..I though the board was bad,,(at first-until I tried it in my big red.

If I put this MVS board in a Jamma cab, would I get sound at all? I'm almost positive this is wired perfectly for MVS (jamma games play no sound at all... the D button is already wired in the right spot)... And, what wire did you find wasn't in the right spot? I've looked this up, and when caps go the left sound fades first... it's got all the symptoms of bad caps.
 

chris1

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Spike Spiegel said:
If I put this MVS board in a Jamma cab, would I get sound at all? I'm almost positive this is wired perfectly for MVS (jamma games play no sound at all... the D button is already wired in the right spot)... And, what wire did you find wasn't in the right spot? I've looked this up, and when caps go the left sound fades first... it's got all the symptoms of bad caps.


I forget what ground wire it was,but it was one of the black ground wires at the end of the harness...For some reason it wasn't in the right spot not matching up to the MVS manual wiring schematic.

I think you will get a one sided,right or left speaker sound only if you put an MVS board in a Jamma harness./thus one speaker will be real low..
Atleast that's how mine was until I found out it was wired for jamma.


Sorry,
It's been along time since I've messed with anything jamma..the MVS boards have been in the cabs for probably 4 years now..i sold ff all my jamma stuff.
 

Spike Spiegel

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chris1 said:
I forget what ground wire it was,but it was one of the black ground wires at the end of the harness...For some reason it wasn't in the right spot not matching up to the MVS manual wiring schematic.

I think you will get a one sided,right or left speaker sound only if you put an MVS board in a Jamma harness./thus one speaker will be real low..
Atleast that's how mine was until I found out it was wired for jamma.


Sorry,
It's been along time since I've messed with anything jamma..the MVS boards have been in the cabs for probably 4 years now..i sold ff all my jamma stuff.

Again, I wish it was that easy, but it just isn't. The left side is lower, but it's not "real low"... took me a bit to see that it was indeed lower than right, but still you can hear it. The select button is wired up, the D buttons are wired. It's just plain and simple a capacitor thing. Going to replace them tonight and pray to god I don't ruin anything (can't be that hard, I guess). Just wish I knew I was buying a project.... sigh.
 

chris1

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Spike Spiegel said:
Again, I wish it was that easy, but it just isn't. The left side is lower, but it's not "real low"... took me a bit to see that it was indeed lower than right, but still you can hear it. The select button is wired up, the D buttons are wired. It's just plain and simple a capacitor thing. Going to replace them tonight and pray to god I don't ruin anything (can't be that hard, I guess). Just wish I knew I was buying a project.... sigh.


Good luck with the replacements of the caps...

LMK how it turns out..
 

TheOmen

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I already love this forum! I'm having the exact same problem with mine. Thanks for the great info!

I get a high pitched really low level squeal. In the right speaker I get really faint audio. When I hooked some powered PC speakers to the headphone jack I get great audio quality!

Guess this is what I get for picking up three 4slot machines for 75 bucks... What a deal!
 

dabadking

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Did you ever find out which capacitors to replace for sound issues? I just got a new cab and am a complete noob when it comes to repairing these. However I have an electrician friend who will replace them for me so i needed to order those capacitors as well as the ones responsible for a dim monitor. Figured even if it ISNT either of those... they will be new and its a semi cheap fix for future care. Thanks :)
 

channelmaniac

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I sell cap kits on my website for the Neo boards... and have a free guide in the downloads section that shows what to replace.

RJ
 

dabadking

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i ordered one today from your site actually..... i think i have a bigger issue now though ; ; .... tonight i turned the cabinet on to show a friend and i had VERY low sound (originally it was just semi low)... it was very cold out but shouldn't be a big prob (its in my garage til i replace the caps and power supply), and it made a slight crackling noise ...like a sparking sound but it wasn't showing visible sounds of anything... it got loud enough to worry and I pulled the plug.. Any suggestions? I didn't want to cause any damage... ><
 

Tyranix95

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Hhmmm.......interesting.

It's been cold and wet in So. Cal. lately.

Curious:

0. What kind of NEO cab do you have?
1. What kind of NEO board is inside it?
2. What game carrt(s). are in what slot(s)?
3. When you turned the cab on, what type of screen did you see--black, cross hatch, game, ect.?
4. Wen did you begin to hear the "crackling" sounds?
 

malignantpoodle

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Why not read the caps on the board itself to see what you need? Also, the board has printing on it for the cap values, along with the polarity orientation.
Just replace all of the electrolytic caps. Almost all of them are the sound anyway.
 

dabadking

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. What kind of NEO cab do you have?
original 4 slot (oldest model)
1. What kind of NEO board is inside it?
2. What game carrt(s). are in what slot(s)?
I had only just gotten this cabinet so I had only used real Bout Fatal Fury Special in slot 1 (got cross hatch), slot 2 worked but was touchy (assuming it needs cleaning though)
3. When you turned the cab on, what type of screen did you see--black, cross hatch, game, ect.?
when the crackling started the screen went blank and started flashing (but still mainly stayed black)
4. When did you begin to hear the "crackling" sounds?
played it for about 2 minutes but sound was much lower than it was before.

Why not read the caps on the board itself to see what you need? Also, the board has printing on it for the cap values, along with the polarity orientation.
Just replace all of the electrolytic caps. Almost all of them are the sound anyway.
Im still really new on this so i hadn't done any of that yet... mainly because i didn't want to start poking around on what i didn't know, or make something worse.

since then heres what Ive found out:

The popping was due to (what i believe is called) the Flyback Transformer (black box.. red cable sticking out of the top to the monitor).Spark is coming out of that.
(I recorded a video of it as well, but haven't uploaded it anywhere yet).
I have a 25" Zenith G-A63ADG25X 04RC0105-005 monitor, and a
Wells gardner Model No. 25K7191 Flyback .... assembly?... whats that whole kit piece officially called?
Ive heard you can replace the flyback piece by itself but i'd like to just replace the whole assembly.
Monitor was Discharged and everything is out of the cabinet and ready to be replaced... just hard to find the parts :(
I wish someone would make STANDARD def LCDs specifically made to replace arcade monitors since CRTs are no longer made :(
that gave that same old school look.... Everyone else probably knows way more than me about this stuff but if it helps anyone I can always get a way to post my video.
Even though i see where the spark is coming from, theres still no visual signs of damage.... kinda weird... no cracks or anything in that spot, but OBVIOUSLY its there XD..
Ive asked a few of the sites that sell parts for the monitors if they have the replacement part, but if anyone runs across one please let me know.
Thank you everyone for helping :)
 

NEO-GEO man

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CRT are still made. VDC in Florida still make them. You can also get them from alot of other places too.
 

Tyranix95

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Sound to me like you have a MVS-4-25 (ver. 1) cab. with a MV-4H MVS mobo and RBFFS cart.

The low sound issue is probably due to bad caps in the audio section. Replacing all the caps in the audio section ought to fix the problem.

As for the MVS cart cross hatching in Slot 1 and working in Slot 2, cleaning the cart and the slot is a good place to start. For a good, simple, quick and easy cart. and slot cleaning use rubbing alcohol and a cotton swab or cloth. To clean the cart.: Wet the Q-Tip and rub it along both sides of the cart. contacts. Repeat until swabs stop picking up dirt. Let the cart dry before using. To clean the slot: Wrap the thin cotton cloth around the club card, wet the cloth, and insert it into the slot, just like a MVS cart. Repeat until swabs stop picking up dirt. Let the slot dry before using. If that does not work, then there are other, more thorough, cart. and slot cleaning methods you can try--like an eraser or contact cleaner.

I don't know much about monitors, except that, IMHO, arcade games look AMAZING on a arcade CRT compared to LCD.
 
Last edited:

Dion

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Just repair that k7000 monitor. They are good, common monitors with parts readily available. Flybacks are kinda hard to find right now but the replenishment run out of china is supposed to hit in January. There are places that have them right now but the usual cheaper places are out. If you want me to replace the fly for you I can do it for a small fee.
 

NEO-GEO man

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Dont they have a US made HV transformer in them to start with? Are we really SURE it needs replacement yet??

If it is arcing, the FIRST move is NOT replace unless its the transformer that is arcing. Clean the anode lead with alcohol, as best you can, then put on some neutral cure silicone where it was arcing, and allow 24 hrs to cure before turning it on. Almost ALWAYS will fix the arc. If it doesnt, you CAN cut and splice in a new anode lead, and its good to go again.

Just cause the anode lead is arcing you dont go and replace a perfectly good HV transformer.

Have a look here: http://www.curtpalme.com/HV_Lead_Splicing.shtm if you want to cut and spilce a HV lead...
 

dabadking

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Thanks for the help :) I'll look into that. Is there any other areas I have to take care to NOT touch after the monitor has been discharged? Like the lights that say caution high voltage or the flyback it's self? Or is all that clear after discharging the monitor?

Anyone near San bernardino know if "the pinball doctor" is reputable? I'm awaiting an answer back from him and if he doesn't reply on a quote I'll update here on needing a service since I can't create a thread or p.m yet..

On a side note... Anyone ever thought about SELLING custom mvs covers on eBay or something? Might be worth some thought :)
 
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