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
- Pin 1 = 4.95v
- Pin 10 = 4.95v
- Pin 22 = 2.85v
- 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 all I can hope for is someone to provide addtional advice to see if I can get it up and running
Current result: still not working – will update accordingly
