What's new
By:
Filters

MVS 4 Slot MV4 Capacitor List?

Hansuke

Hansuke

Student
Joined
Aug 14, 2020
Messages
24
Reaction score
4
Location
United States
Does anyone have a cap list of the audio section of the MV4? Including the mylar caps?

Trying to solve an issue with crackly sound when loud sounds are played. Happens in all 4 slots, no amount of cleaning the volume pots and slots seem to alleviate the issue.

It sounds similar to this.

After some looking around, apparently it's a high chance the mylar caps are to blame.

So I was wondering if anyone has a complete cap list of the entire audio section including the mylar caps?
 
Hansuke said:
Those are just the electrolytic caps, I'm also looking for a list of the mylar caps as well.
Click to expand...
Ah, gotcha...

But aren't they marked? I see 223M for example, which should be 0.022uf.
 
Last edited:
Kujako said:
Ah, gotcha...

But aren't they marked? I see 223M for example, which should be 0.022uf.
Click to expand...
They should be marked. I'm actually talking to Console5 about it and even though I sent them scans of the board from mvs-scans, they still want me to look at the board and send them pics of the caps themselves.

So I was wondering if someone has already done this and maybe there's some discrepancy or mix-up of some kind.
 
Hansuke said:
They should be marked. I'm actually talking to Console5 about it and even though I sent them scans of the board from mvs-scans, they still want me to look at the board and send them pics of the caps themselves.

So I was wondering if someone has already done this and maybe there's some discrepancy or mix-up of some kind.
Click to expand...

Looking at this scan here [LINK] reenforces what I recall when I had mine apart not too long ago. The components are stenciled onto the PCB. That was one of the nice things about working on the system, didn't need to match the removed component just needed to match what the PCB stencil said should go there. But I've not tried to read the markings on the capacitors themselves and unfortunately I've put my MV4 aside for now. but if you're unable to make progress and find the PCB stenciled values unreliable I can dig it out.
 
Kujako said:
Looking at this scan here [LINK] reenforces what I recall when I had mine apart not too long ago. The components are stenciled onto the PCB. That was one of the nice things about working on the system, didn't need to match the removed component just needed to match what the PCB stencil said should go there. But I've not tried to read the markings on the capacitors themselves and unfortunately I've put my MV4 aside for now. but if you're unable to make progress and find the PCB stenciled values unreliable I can dig it out.
Click to expand...
That won't be necessary for now.

Thanks a lot for the offer though!

I've ordered a replacement cap kit for the electrolytics and we'll see if anything changes for the better after those get replaced.
 
On the newer MV2F and MV4F (and FT/FT2) boards the audio will do that and get worse to where the audio amp chip oscillates and makes huge thumping sounds. When it does that it spikes the power supply so hard it causes the +5v to sag. This will happen if the power supply is noisy and the 470uf filter caps on the PCB dry out. Make sure you're replacing all the caps in the audio section, not just the ones carrying audio signals.
 
channelmaniac said:
On the newer MV2F and MV4F (and FT/FT2) boards the audio will do that and get worse to where the audio amp chip oscillates and makes huge thumping sounds. When it does that it spikes the power supply so hard it causes the +5v to sag. This will happen if the power supply is noisy and the 470uf filter caps on the PCB dry out. Make sure you're replacing all the caps in the audio section, not just the ones carrying audio signals.
Click to expand...
Thanks for the heads up!

I've replaced all the electrolytic caps on the MV4 and it has cleared up a lot of clarity and loudness issues.

However, I still get that crackling on high notes and lower bass sounds are distorted. It sounds the same no matter what the volume pot is at, besides the loudness of the audio of course.

I've tried replacing the YM2610 and there is no difference in the audio. I managed to get a headphone adapter cable and for some reason both left and right channels are coming out of the left speaker from the headphone output. The audio crackling on highs and low bass distortion sound the same coming through the left speaker of the headphone output.

I'm not sure what could be causing both audio channels to output to only the left speaker on the headphone output...

Thinking about replacing the YM3016 DAC to see if that fixes the high crackle and low bass distortion.
 
Update post:

Replaced the YM3016 DAC, no change sadly.

I'm now kind of stumped on how to proceed...

Any suggestions would be welcome.
 
Maybe check the capacitor to ground connected to YM3016 pin 13. 68pf, labeled C3 on the AES schematic.
On one of my boards it was broken and I thought it was a standard 100nf bypass, and I got very muffled sound with that value, so it does some filtering. Put a 68pf back and sound was normal again.
 
channelmaniac said:
On the newer MV2F and MV4F (and FT/FT2) boards the audio will do that and get worse to where the audio amp chip oscillates and makes huge thumping sounds. When it does that it spikes the power supply so hard it causes the +5v to sag. This will happen if the power supply is noisy and the 470uf filter caps on the PCB dry out. Make sure you're replacing all the caps in the audio section, not just the ones carrying audio signals.
Click to expand...
Listen to the Jedi Massah, all.
 
channelmaniac said:
Video please?
Click to expand...
Here are video examples. Sorry for the bad quality, never filmed CRTs before.

Blazing Star Intro:


Samurai Shodown: Intro & Nakoruru's Stage:


Samurai Shodown: Hanzo's Stage:


The highs in the Blazing Star intro have crackle to them and highs in the SamSho intro have crackle too.
The low bass sounds in Nakoruru and Hanzo's stages sound distorted. It sounds like the speakers are blown out, but that's what it actually sounds like coming from the MV4...

It sounds like that no matter what the volume slider on the board is at. It's definitely not the speakers because I've tried out a 1 slot and 2 slot MVS and they sound flawless on the same setup. I also hooked up the 4 slot to the goldie cab and I was able to hear the same crackle/distortion from that too.

So it's most likely the 4 slot MV4 itself that has the issue.
 
Hansuke said:
I'm not sure what could be causing both audio channels to output to only the left speaker on the headphone output...
Click to expand...

Doesn't come across well on the video... Can you post pics of the audio section - top and bottom of PCB? I wonder if you have some jumper wries or something weird hooked up since you say you only get both audio channels from the left speaker on headphone output.
 
channelmaniac said:
Doesn't come across well on the video... Can you post pics of the audio section - top and bottom of PCB? I wonder if you have some jumper wries or something weird hooked up since you say you only get both audio channels from the left speaker on headphone output.
Click to expand...
I currently don't have any equipment that allows me to record audio directly from the source. I may try to get some later, but it does sound very similar to the sound clip linked in the first post.

20230218_181421 - Copy.JPG

Haven't gotten around to cleaning the flux from the recap or the dust that was originally on it. It looks a million times worse on camera than in person.

Could the headphone amp IC be faulty causing the combined audio to come out the left channel?
 
You must log in or register to reply here.
Back
Top