Assistance with CPS3 mobo with no sound

[tiff_lee]

So I couldn't see any obvious logic chips on the board that would be dividing that crystal oscillator frequency (/3) so I surmised that it was being done by one of the custom chips. I soldered a piece of kynar wire to pin 8 of the exchange switch (PI5C3383Q, which as per above I said was the incoming 14Mhz clock) and probed the board until I found the other end of it .

Good news I found the other end.

Bad news it is coming from the PPU, Pin 91.

So knowing that I would check for continuity between those pins with the board off (pin 8 PI5C3383Q and pin 91 PPU), if it's good then that rules out a broken trace (if the trace is indeed broken check for activity direct at the PPU chances are it will be active and then just run a repair wire and retest). Then fire up the board and check for activity with the logic probe at either pin 8 of exchange IC or at PPU 91 whichever you find easiest, obviously a scope would be better but any activity is going to be better than what you have so far.

If there is activity then investigate the exchange IC more (as per the above post, supply, enable signal etc), if there is no activity then the issue is PPU related whether that be a lack of input clock to the PPU or a defective PPU I have no idea at this time i've not looked any further.

 

[ShootTheCore]

Great job tracking down the source of the clock signal!

 

[tiff_lee]

Yeah just waiting for Julius @mR_CaESaR to pull his finger out and stop blaming his misses for not cracking on using the kitchen table!

 

[mR_CaESaR]

Managed to test some things tonight.

On the quiet board

- There is continuity between the 6D exchange switch pin 8 to PPU pin 91
- Pin 1 = Hi
- Pin 8 = just flashes (same as pin 91 on the ppu)
- Pin 9 = Lo
- Pin 10 = nothing
- Pin 11 = Lo
- Pin 12 = Lo
- Pin 13 = Lo
- Pin 24 = Hi

I guess the next real step is to change the exchange switch?

 

[tiff_lee]

On the quiet board

- Pin 1 = Hi

Pin 1 being Hi is a problem

Pin 1 Low, Pin 13 Low = B1 > D1
Pin 1 Low, Pin 13 High = A1 > D1

I didn't mention it before but from the data sheet there is a third state on the truth table ( I didn't mention it as I didn't think it was the issue, my bad).

Pin 1 High, Pin 13 in any state = OFF, high impedance between input & output pins

So if the exchange switch is in that state a quick and dirty test to get audio working would be short pins 8 & 9 which will effectively put the clock signal to your DAC (since you have now confirmed there is a signal there and it's connected to the PPU).

The real issue now though is to find out why is that switch 'turned off', Pin 1 Bus enable needs to be low and something is holding that pin high.

 

[GoldenGlover]

I’m following this thread with fervor as I am literally in the same boat as you @mR_CaESaR with a CPS3 that works perfectly aside from no audio via JAMMA or RCA. I’ve replaced the DAC & amp chip & even substituted 6D from a parts board I have & still have dead audio. I too also have continuity from pin 91 of the PPU to pin 8 of the relay at 6D.

Could it be the crystal that’s the problem here?

 

[tiff_lee]

Could it be the crystal that’s the problem here?

Depends what else uses that 42.9545mhz clock signal if that was defective would the board even function? the clock from the PPU is a derivative of that main clock, so is the 42 mhz clock going in and the actual 14 mhz clock coming out?
I haven't looked into it too much more as fortunately I don't have this problem but perhaps you could fit an external counter to the 42 mhz oscillator output and derive that 14 mhz clock externally (from the PPU) and then feed that into the DAC clock circuit. I dunno just spit balling.

 

[mR_CaESaR]

Haven't really done much for a while on it, I think I'm well and truly out of my depth.

I spent some time with it with @tiff_lee assisting and tried to get sound by making the switching bus 6d act like it was switched to activate the audio, but I still didn't get any sound. Based on the info on the datasheet, the IC is doing what it's supposed to be doing, the problem is why is the state of the pad the state it is. Unfortunately I haven't really had the chance to look further into it.

 

[chacal231077]

Hi

I have a similar problem but with the External RCA output

I have no sound, only on the Jamma output.

A weird thing is that I hear sound from the Jamma connector when I select the External output

I have already changed the 2 LM833N, TA8201AK, C383 and still no sound in external RCA.

An idea

 

[hatmoose]

Hi

I have a similar problem but with the External RCA output

I have no sound, only on the Jamma output.

A weird thing is that I hear sound from the Jamma connector when I select the External output

I have already changed the 2 LM833N, TA8201AK, C383 and still no sound in external RCA.

An idea

Sound at the Jamma edge is already amplified, sound out of those RCA adapters was intended to go into a Qsound amp (although any amp will work). Without amplification any sound off those RCA ports will be inaudible

 

[chacal231077]

Sound at the Jamma edge is already amplified, sound out of those RCA adapters was intended to go into a Qsound amp (although any amp will work). Without amplification any sound off those RCA ports will be inaudible

Hi!

yes I understood.

Usually I always go through the RCA sound output to the amp of my New Net City to cite my CPS2 as an example.

For my other PCB in Jamma, output Jamma sound through my JVS adapter to Jamma River Service, and then to the New Net City sound amplifier.

However, the CPS3 with its RCA functions normally like a CPS2 with its RCA

So what is the problem ?

I have a Qsound amplifier, but that won't change anything I think.

​

 

[chacal231077]

Hi!

I did exactly like mR CaESaR

I changed the same components and I still have no sound on the RCA outputs, just a hiss when I push the sound potentiometer to the maximum

I don't understand why I have sound on the Jamma output but not on the RCA outputs , yet I selected external in the CPS3 stup

 

[mR_CaESaR]

I'm sorry, I can't help any further. At least you have sound from jamma, I got no sound at all.

I'll send my pcb to @cruzlink2 hopefully in the next month for him to have a poke around and see if he can fix it for me.

The only thing I can think of is maybe check for continuity on the rca metal parts to the corresponding pin at the bottom

 

[chacal231077]

Hi! !

Problem solved

I was fooled like a beginner

Looking at the motherboard that I have from a friend, I noticed the back of its original RCA connector with a central pin.

I'm telling you this because for a question of aesthetics I put a new connector which is not wired like the original one.

I put this connector there, look at his footprint but what a cockroach I am

I put the original one back and I have the sound on RCA output ​

​

PJRAN2X1U01AUX​

 

[mR_CaESaR]

I didn't realise you didn't have an original rca socket in your motherboard.

Glad reverting back to the original worked for you. Congrats!

 

[chacal231077]

I didn't realise you didn't have an original rca socket in your motherboard.

Glad reverting back to the original worked for you. Congrats!

Thank you

 

[tacobell]

I purchased a CPS3 mobo only from YAJ a little while back in hope that it would work, but unfortunately my YAJ luck has run out (previously most "junk" stuff I've purchased has been perfect, but sadly this time it's not so much the case )

When the CPS3 arrived, it looked immaculate!

I loaded up my simms and DS cart and proceeded to write 3s into the SIMMS. 45 mins or so later, it wrote successfully and here I am thinking we have a winner...

As the Capcom Logo came on and the attract mode started to play, there was no sound. I thought it may have been because the audio setting was configured for external, so I checked that and it was configured for JAMMA, but I then swapped it over to external and plugged in to an external amp still no sound. I played around with the volume pot but there was no crackling or anything like that, cleaned the pot with IPA and still no change. I thought, let me change the volume pot as those seem to be one of the troublesome parts on this system.

After I took the cart off, the whole cart socket also came without, the CPS3 is now without a socket and sound. Great!

Cleaning this out proved to be quite a time consuming exercise as every time I used the desoldering gun, it didn't work like it does if the pin was properly secured with the cart, so there was a lot of soldering with tweezers and then wicking the area. We got there in the end

However, it wasn't without casualties. I didn't realise until I was cleaning that I had accidentally wicked off a resistor.

No love lost as I was able to get it off another board that's broken.

Cart arrived after a few days from ordering at digikey and within minutes, a new cart with a might firmer grip on the cart was installed.

Information of the CPS3 was used from this page https://github.com/dankan1890/mewui/blob/master/src/mame/drivers/cps3.cpp

With advice/help from @xodaraP and @cruzlink2, I've managed to do the following:

• Changed cart (I ordered these ones as they had a metal brackets and not plastic like the original ones - the plastic was the reason the originals broke for me. The plastic mounts can be found on this link)
• Changed the Sound Amp, Toshiba TA8201AK IC; no change
• Confirmed the sound amp was receiving voltage; confirmed with 12v with red probe on pin 6 and black probe on pin 4

• Changed the volume pot; no change
• Checked to see if it was isolated to jamma edge, changed to external in the settings and sent to external speakers; no change.
• Checked to see if there's continuity between GND and 12v; no continuity
• Replaced the LM833N chips; no change
• Checked the DAC for data, ws, bck and confirmed there's continuity on the resistor array RN3 (pin 6 = dat, pin 5 = ws, pin 4 = bck)
• Checked the voltages on the DAC based on the following schematic

1. Pin 1 = 4.95v
2. Pin 10 = 4.95v
3. Pin 22 = 2.85v
4. Pin 23 = 4.95v

• Removed the DAC and confirmed every pin had continuity to the next point

• Replaced the DAC; no change

Everything that's been replaced lol

At this point, I am completely out of ideas and I believe I've done pretty much everything I'm capable of doing. My knowledge of PCB repair or the CPS3 is very limited, I don't have a logic probe, oscilloscope to further do any more troubleshooting, so I'm really now at the hope someone else has experienced a very similar issue and was able to fix by changing a part. TIA

I’m having an issue where sound is cracking on both the JAMMA and the RCA outputs. I’ve replaced all of the sound related items with no change: Toshiba Sound Amp IC, volume pot, lm833n chips, and TDA1306T DAC.

Tested some of these chips at 5v and noticed some chips aren’t getting enough voltage:
https://www.arcade-projects.com/threads/cps3-sound-problem.811/post-436082

I noticed that when increasing the voltage around 5.3v the cracking sound disappears.

I’ve cleaned all the contacts and reflowed the custom 3329 chip. I’ve also checked all the grounds associated with sound and they seem to be fine. I’m not sure what’s making the drop on voltage in these chips.

I’ve been following this thread, along with the help of @RGBand & @cruzlink2 but so far its still cracking.

 

[TheCrow]

I’m having an issue where sound is cracking on both the JAMMA and the RCA outputs. I’ve replaced all of the sound related items with no change: Toshiba Sound Amp IC, volume pot, lm833n chips, and TDA1306T DAC.

Tested some of these chips at 5v and noticed some chips aren’t getting enough voltage:
https://www.arcade-projects.com/threads/cps3-sound-problem.811/post-436082

I noticed that when increasing the voltage around 5.3v the cracking sound disappears.

I’ve cleaned all the contacts and reflowed the custom 3329 chip. I’ve also checked all the grounds associated with sound and they seem to be fine. I’m not sure what’s making the drop on voltage in these chips.

I’ve been following this thread, along with the help of @RGBand & @cruzlink2 but so far its still cracking.

Have you checked the transistors on the sound portion of the board , i had a similar issue and one of them was giving off readings, replaced it and got sound back