No Sound on 6-Slot PCB

cgbartek · Apr 24, 2007

I picked up an untested 6-slot recently and was surprised to see that it booted up and played games perfectly, except there is no sound at all. I've tried hooking up headphones, test mode, using the sliders, and swapping the Z-80. No luck. I'm 90% sure the 12v is working, but I'll test that out tomorrow for sure. I'm plugged into an MVS harness.

Anyone have an idea? Maybe the capacitors or the amp?

Thanks,
Chris

Xian Xi · Apr 24, 2007

cgbartek said:
I picked up an untested 6-slot recently and was surprised to see that it booted up and played games perfectly, except there is no sound at all. I've tried hooking up headphones, test mode, using the sliders, and swapping the Z-80. No luck. I'm 90% sure the 12v is working, but I'll test that out tomorrow for sure. I'm plugged into an MVS harness.

Anyone have an idea? Maybe the capacitors or the amp?

Thanks,
Chris

Probably your PSU.

mainman · Apr 24, 2007

cgbartek said:
Anyone have an idea? Maybe the capacitors or the amp?

Thanks,
Chris

There you go

channelmaniac · Apr 24, 2007

If it plays then the Z80 and the sound subsystem is fine.

You need to check the pre-amp and amplifier sections as well as the power supply - both the external PSU and the 5v regulator on the MVS board.

This is where an oscilloscope or a logic probe comes in handy. You can actually take a logic probe (one that has sound beeps) and hear the sounds from the board as you trace the audio circuits.

RJ

cgbartek · Apr 25, 2007

Okay I tested the board in a few other MVS cabinets to make sure it's not the PSU... it still has the exact same problem. I guess the next step is to test the amp. I'm mostly confused about why no sound would come from the headphones; it should be able to output to the headphones without the amp working, right? What would cause the sound to quit working completely?

Xian Xi · Apr 25, 2007

Like someone said possibly the caps.

mainman · Apr 25, 2007

cgbartek said:
Okay I tested the board in a few other MVS cabinets to make sure it's not the PSU... it still has the exact same problem. I guess the next step is to test the amp. I'm mostly confused about why no sound would come from the headphones; it should be able to output to the headphones without the amp working, right? What would cause the sound to quit working completely?

Yes the audio coming off the earphones and the harness do have independant pre amps. So using that logic the problem will be somewhere before the signal reaches these two or a other wise shared common problem.

As I said earlier there a 80 percent chance you have a bad capacitor in the audio circuit. As capacitors age they wear and their capacitance drop which inversely increases resistance across the device which decreses the audio ouput signal at the power amp. You could be anal and try to trace the failure to the signal faulty component with a meter which in the end is slightly faster provided there are no other components in series that will give misleading measurement, I say start with the 470 micro farad cap first. Or you can play it safe and just replace all the caps which will take longer but in the long run will have the benefit of not having to worry about another cap failing.

I'm not talking through my ass here, I have seen and repaired this failure countless times.

ttooddddyy · Apr 26, 2007

The 6 slots being large boards may be prone to broken/cracked traces (could be caused by over exertion force of carts from the top board), check continuity around the op amps and output stage. If it was in the digital proc you would usually get the Z80 error. Try flexing the board whilst it is running.
It may be an electro

NEgO MANIAC · Apr 26, 2007

My 6-slot also has sound issues. No sound through the earphones and very weak sound through the speakers. If I let the board warm up, it does get louder, but not loud. I would love to know what is causing this and get it fixed.

MKL · Apr 26, 2007

No sound from the jacks is regular on 4- and 6-slots. They're not the same as the jacks on a 2-slot. Headphone out is the 4-pin header nearby.

cgbartek · Apr 26, 2007

NEgO MANIAC said:
My 6-slot also has sound issues. No sound through the earphones and very weak sound through the speakers. If I let the board warm up, it does get louder, but not loud. I would love to know what is causing this and get it fixed.

Your problem is most definitely the capacitors. I guess I'll try to do a capkit on mine, it probably needs one anyway and it's a good place to start.

ttooddddyy said:
The 6 slots being large boards may be prone to broken/cracked traces (could be caused by over exertion force of carts from the top board), check continuity around the op amps and output stage. If it was in the digital proc you would usually get the Z80 error. Try flexing the board whilst it is running.

This 6-slot is in pretty ugly shape on the bottom and sides, there are some torn up traces but none of them are anywhere near the audio portion. I'll try the flexing thing for sure.

MKL said:
No sound from the jacks is regular on 4- and 6-slots. They're not the same as the jacks on a 2-slot. Headphone out is the 4-pin header nearby.

Interesting, I didn't know that. I'll try hooking the 4-pin in my 4-slot cabinet to the 6-slot and maybe I'll get sound then. It's worth a shot.

Chris

cgbartek · Apr 26, 2007

Thanks again for your advice MKL, I hooked up the headphone cable to the board, and now I can hear the sounds in test mode (I haven't tried the games but I would assume they play sounds). I waited about 10 minutes for the caps to warm up but still heard absolutely nothing coming from the speakers. I guess my plan of action is to do a capkit anyway, then replace the amp if need be. Does anyone have a list of the caps on the 6-slot, or know of a place I can get a YM2610?

Chris

NEgO MANIAC · Apr 26, 2007

cgbartek said:
Thanks again for your advice MKL, I hooked up the headphone cable to the board, and now I can hear the sounds in test mode (I haven't tried the games but I would assume they play sounds). I waited about 10 minutes for the caps to warm up but still heard absolutely nothing coming from the speakers. I guess my plan of action is to do a capkit anyway, then replace the amp if need be. Does anyone have a list of the caps on the 6-slot, or know of a place I can get a YM2610?

Chris

I'm interested in list of caps that need to be replaced for sound. Also, cap location on the board would help too.

ttooddddyy · Apr 27, 2007

cgbartek said:
then replace the amp if need be.

An easy way to check the amp, If you get a hum or buzzing sound when you touch the input pins with your finger = the audio output stage is OK.

MKL · Apr 27, 2007

cgbartek said:
I guess my plan of action is to do a capkit anyway, then replace the amp if need be. Does anyone have a list of the caps on the 6-slot, or know of a place I can get a YM2610?

The amp is not the YM2610 (which is good if you get sound from the headphone connector) but the HA13001. Before replacing that you should replace the capacitors shown in this scheme (esp. 1, 2, 3, 4, 7, 8, 10, 11):

http://img228.imageshack.us/img228/8784/mvsaudio3ay5.jpg

Also, check the speaker volume pot.

channelmaniac · Apr 27, 2007

The YM2610 is the sound generation IC. If you have sound coming from the headphone jack it is working fine.

The YM3016 is the D/A converter for the audio stream coming from the YM2610. If you hear sound coming from the headphone jack it too is working fine.

RJ

Spike Spiegel · Oct 10, 2007

MKL said:
The amp is not the YM2610 (which is good if you get sound from the headphone connector) but the HA13001. Before replacing that you should replace the capacitors shown in this scheme (esp. 1, 2, 3, 4, 7, 8, 10, 11):

http://img228.imageshack.us/img228/8784/mvsaudio3ay5.jpg

Also, check the speaker volume pot.

With what caps do I replace these? Which parts number go to which one?

MKL · Oct 10, 2007

Spike Spiegel said:
With what caps do I replace these? Which parts number go to which one?

They're all electrolytic capacitors, values/ratings are written on them, what else do you need to know? How to locate them on the PCB? It shouldn't be that hard with the scheme but if you just can't figure out yourself post a pic of the area and I'll circle them for you.
Note that you want the replacement caps to not only match the capacitance values (e.g 100uF, 470uF, etc.) but also the voltage ratings (e.g. 16v, etc.) because if you get a higher rating the caps will be bigger/taller and you might have problems putting the top board back on.

Spike Spiegel · Oct 10, 2007

MKL said:
They're all electrolytic capacitors, values/ratings are written on them, what else do you need to know? How to locate them on the PCB? It shouldn't be that hard with the scheme but if you just can't figure out yourself post a pic of the area and I'll circle them for you.
Note that you want the replacement caps to not only match the capacitance values (e.g 100uF, 470uF, etc.) but also the voltage ratings (e.g. 16v, etc.) because if you get a higher rating the caps will be bigger/taller and you might have problems putting the top board back on.

Yeah, I noticed that after asking... sorry. My final question is this: how do I take that top deck off the bottom one (not home yet, so it's not in front of me). I assume it just unplugs, yes? Seems simple enough.

channelmaniac · Oct 10, 2007

Dude...

Before you mess it up, ship it to someone that can do it for you... You should've seen some of the boards I've repaired that someone else tried to repair first. Urg. First I had to fix their damage then fix the board's problem.

Where are you located? There are several members around that can help you with the work, for cash or for trade.

RJ

No Sound on 6-Slot PCB

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