MV1FZ no sound

[Coyo5050]

Picked up a MV1FZ awhile ago and got around to testing it today. I get video but no sound of any sort. It originally had no video either and I thought I did a sound test that worked but I must be imagining things.

Where should I be looking first?

Thanks!

 

[yavuzg]

If you can play games then its not the Z80.

Personally I never saw a bad YM2610 either...

So, it could be;

1) bad volume pot
2) bad electrolitic capacitor around sound region
3) bad amplifier IC (most probably)
4) bad speaker wiring?

When you play with the volume pot, do you hear at least a hum or a hiss sound? Or if you tap the capacitors with your finger do you hear anything?

During the above simple tests, if the PCB is still dead silent then most probably the amplifier IC is fried...

 

[Darksoft]

Check the caps. If any of them looks bulky, it's bad.

 

[Niko]

Are you running it in a cab, or supergun? Sound is driven by 12v on the neo, have you verified voltage?

 

[Coyo5050]

Are you running it in a cab, or supergun? Sound is driven by 12v on the neo, have you verified voltage?

running on my supergun which has a display for the 5v. Pushed it up to 5.25 and back down again no dif which would have adj the 12v too

 

[Darksoft]

Check with a multimeter.

 

[Coyo5050]

If you can play games then its not the Z80.

Personally I never saw a bad YM2610 either...

So, it could be;

1) bad volume pot
2) bad electrolitic capacitor around sound region
3) bad amplifier IC (most probably)
4) bad speaker wiring?

When you play with the volume pot, do you hear at least a hum or a hiss sound? Or if you tap the capacitors with your finger do you hear anything?

During the above simple tests, if the PCB is still dead silent then most probably the amplifier IC is fried...

Getting back to this project.

Cleared RAM.

Checked with multimeter at board edge to verify voltage. 12v looks good.

I am getting humming hissing that gets louder or softer when I turn the volume up and down with the pot on the board.

Speaker wiring is giving me the noises and works with other boards.

Caps have a lot of glue on them but they all look fine, no bulging.

 

[jassin000]

I 2nd the bad amp/IC, I blew up the audio amp on one of my 1FZ's by plugging it into a Wei Ya PSU WITHOUT using a 100v Japanese stepdown converter.
The 12v line fluctuate so wildly (multi meter registered a 16v spike at one point) it pop'd the amp.

Moral? Never use Wei Ya PSU without stepdown converter (be aware this is the stock PSU for the ENTIRE VEWLIX family)!
The 12v line will beat like a heart, dipping down in the 9v range, then blasting up to the 16v range. *thump*thump*thump*

 

[MRTCPS2]

i have a similar issue, for the most part i don't get any noise but i occasionally do get some game sounds however the game just outputs random sound samples at the wrong times
(e.g neo geo jingle during a round end and results screen in samurai shodown 2)

 

[nem]

Caps have a lot of glue on them but they all look fine, no bulging.

I've recapped a few MVS boards that have had bad caps and the caps have never, ever bulged.

That said, if you don't have any sound, it's probably not a cap issue. Caps are to blame if the sound is really quiet, really loud or wildly fluctuating in between.

 

[Coyo5050]

What part do i need to replace the bad IC?

 

[yavuzg]

What part do i need to replace the bad IC?

Ok. It is a cheap and common part that you won't be too unhappy that you bought a new one if that is not the cause of your problem.

The part is a common amplifier IC used in car audio systems back in the day. It is "HA13001". It is the flat component which its heat sink is fastened to the PCB with two screws. Its the part right next to the volume pot where the silk screen says "POWER-AMP1". Double check with "your" MV1FZ to make sure it is that part.

 

[Coyo5050]

Ordered a HA13001 and a cap kit. Hopefully this will fix the issue.

 

[Coyo5050]

Ok, I replaced the HA13001 and still no sound. When I adjust the volume pot up and down I get nothing. Not even the hissing from before.

So ned to make sure I replaced it right. I had some trouble pulling the old one out so I checked continuity on the replacement from the pins to the board and the ones I could figure out were good. There are 4 pins that dont seem to connect to anything on the board, pins 1, 4, 9 and 10. Are they used?

Havent done caps yet since so far things seem worse since not even hissing sounds anymore.

 

[xodaraP]

I found a schematic about building a basic car amp using the amp IC on the Neo boards (I can't find an English datasheet for it)

https://www.eleccircuit.com/mini-40-watt-audio-car-amplifiers-using-ha13001/

Pin 1, 4 and 9 are connected to ground, pin 10 seems to be the +12 input, not having that might be a problem. Check with your multimeter for continuity between 10 and +12 and the others and GND

 

[bootboy]

If you can play games then its not the Z80.

Personally I never saw a bad YM2610 either...

So, it could be;

1) bad volume pot
2) bad electrolitic capacitor around sound region
3) bad amplifier IC (most probably)
4) bad speaker wiring?

When you play with the volume pot, do you hear at least a hum or a hiss sound? Or if you tap the capacitors with your finger do you hear anything?

During the above simple tests, if the PCB is still dead silent then most probably the amplifier IC is fried...

As yavuzg said you should check that things ... but if you're getting humming/hissing going louder/softer when you turn the volume up/down with the pot the power amp HA13001 should to its work, by the way you already replaced it and the audio issue is still there.

if something in the digital part of the audio circuit was bad the startup test should rise at least a Z80 error, so you should focus on the analog section of the circuit.

Look at the attached picture, the ICs in the yellow square are the DIGITAL part of the circuit, you should check the ANALOG part the RED bordered one.

The audio chain is the following:

(DIGITAL) Z80/YM2610 > DAC YM3016 (DIGITAL-ANALOG CONVERTER) > OPAMP uPC844g > POWER AMP HA13001 > JAMMA

So you should check the DAC and the OPAMP, they are light-blue dotted.

Which tools have you available for troubleshooting?

 

[Coyo5050]

I just have a multimeter for testing and I have a full cap kit. I used it to check continuity between ground on the JAMMA edge to pin 1,4 and 9 and they were good. Pin 10 to the 12v on the JAMMA edge I didnt get anything and that is def required for sound.

Obvious not permanent solution but quick and easy to test, can I just run a wire between pin 10 and the 12v JAMMA edge to make sure they are connected to troubleshoot or would that bypass something important?

 

[xodaraP]

Ideally you need to find out where the break in the circuit is - the +12 from the JAMMA edge may well go to a regulator etc before it hits the audio circuit (I can't remember how MVS is connected) and may well not be a full 12 volts when it hits the circuit

 

[Coyo5050]

F'd up the HA13001doing something stupid broke a pin off so ordered a new one. Removed it from the board and using the multimeter since I had a nice hole and An not getting continuity.

I cant see the path the 12v on the JAMMA edge gets to the HA13001 so no idea how to check it. Anyone know the path it takes so I can check?