AES3-6 with sound problems

[Demiurgo]

The problem is sound: totally missing. The earphone is also silent. I installed sockets in the BIOS, Z80 and YM2610, and replaced all of them, without any effect.

Socket contacts were cleaned, games had sound in another console, and no noticeable damage to the board was located.

Any ideas, please?

 

[Xian Xi]

Recap the sound section.

 

[Demiurgo]

Now comes the silly question: Where are located the sound related capacitors in a 3-6?

 

[Demiurgo]

Checking the board, there are three zones with capacitors. Top one is related to video, I think. Left one to power, I also guess, and lower zone between controller sockets is the one related to sound, is correct? There are 15 10µ capacitor and 2 470µ there. ¿All must be replaced?

 

[Xian Xi]

Checking the board, there are three zones with capacitors. Top one is related to video, I think. Left one to power, I also guess, and lower zone between controller sockets is the one related to sound, is correct? There are 15 10µ capacitor and 2 470µ there. ¿All must be replaced?

Is there at least a hum from the speakers? If there is then a recap should fix it.

 

[Demiurgo]

Yes, there is a weak humming when I turn volume to the maximum, but no recognizable music or sound. I will replace all these caps then...

By the way, they are 16V. I think no problem if I use 25V instead, right?

 

[Atro]

Yes, there is a weak humming when I turn volume to the maximum, but no recognizable music or sound. I will replace all these caps then...

By the way, they are 16V. I think no problem if I use 25V instead, right?

As long as the voltage is at least equal or above, it is not a problem. Just don't mess with the uF values. Those have to be equal.

 

[GohanX]

Might as well do all the caps if you are doing the sound section imo.

 

[dragonpt]

Might as well do all the caps if you are doing the sound section imo.

Yeah

Others will follow sooner or later...

 

[Demiurgo]

Might as well do all the caps if you are doing the sound section imo.

Well... now I just ordered just the 17 caps for the sound section, and in a couple of days I will receive them. Maybe this weekend I will buy the other 15, but first I want to check if sound returns after the cap replacing.

By the way, here is a picture of the board:

 

[Demiurgo]

After having the capacitors replaced, there is still no sound...

 

[aha2940]

After having the capacitors replaced, there is still no sound...

Absence of sound may mean a broken M1 chip on the cart. You sure your cart has no issues?

 

[Demiurgo]

No, the carts are fine. I tried some games in this console and all are mute, but they sound perfectly in another console.

 

[Demiurgo]

What else should I check?

 

[mikejmoffitt]

You can check the YM3016, which is the DAC for the YM2610. If that's dead, it won't make sound (or can do other messed up stuff). I had to replace the DAC once. If you can hear coin sounds and other few SFX (those using the YM2610's SSG feature), then that's a hint that the DAC is dead.

If you don't even hear the coin sounds, I would suspect the YM2610 or the Z80 in that order.

 

[Demiurgo]

I will try to find a YM3016, remove the old one, install a socket and try it. I did that already with the Z80 and YM2610... I tried two new of each, but still no sound at all.

 

[mikejmoffitt]

You can try probing the audio out pins of the YM2610 directly (using an input to an amplifier for example). The SSG output pins should be clear, while the digital data out will be distorted and scratchy (since it hasn't gone to the DAC yet). However, you can still tell if things are happening or not that way.

 

[Demiurgo]

Can you tell me exactly the pins to check? I do not want to make a mistake there...

 

[Demiurgo]

Socket installed while waiting for the new YM3016 to arrive. Now, obviously, no change: console keeps mute.

 

[Neo Alec]

Here's a similar thread I started:

http://www.neo-geo.com/forums/showthread.php?267652-AES-No-Sound

Xian Xi gave lots of good advice.

 

[Demiurgo]

Thanks for the advice. I was checking for more info in other forums and threads, but this one is new for me. Anyway I think I checked there is no trace cut, but I will try again. My eyes hurt...

 

[Demiurgo]

Before calling an exorcist, I am checking traces carefully. All the pins for the Z80 address bus and data bus are connected to the cartridge slot. Two of them, A0 and A1, also to the YM2610. Next thing will be check the YM2610 pins.

Any advice about other things to try, or how to do it? Must I use a logic probe or an oscilloscope to check something you want to see checked?

 

[Demiurgo]

I found the Z80´s pin 6 (CLK), is connected to the pin 40 (A10), so to the CHA A40, because this last connection must be there. Why the clock signal is also there?

 

[Demiurgo]

I traced the Z80 pin 6 along all the board to the pin 5 of the SN74AS04 located right over the NEO-G0, but I do not understand why that has continuity with the Z80 pin 40...

 

[Demiurgo]

CLK from Z80 is correctly connected to pin 101 of LSPC2, to get clock signal, so I wonder where that mixes with Z80´s A10.