TwinFamicom - missing audio chanel in Disk system part

Hello, I am searching for some help around here, I bought a non working Twin Famicom (non turbo version), fixed a rather trivial fault (bad connection between the main PCB and FDS drive) and it's working again, but the guy who sold it to me was using it for some experiments so, as I found out, some of the capacitors were already exchanged, the 2C33 is socketed and there may be something else exchanged, that I cannot tell...
The problem is that the Disk system part sounds like it's missing one of the audio channels - listen to this Zelda tune recorded from it:
http://www.mediafire.com/?b1a2g330xe7gqve (mp3)
I tried to exchange the capacitors that seemed leaking, but I forgot where to put them back so I asked Drakon for help and I got this image for the right type of capacitors: https://i.imgur.com/ncXTdZk.jpg
Anyway exchanging caps for new and correct ones haven't repaired the missing channel problem.
Any idea what might be causing this? Thanks for any help!
Some detailed pictures of my board (big size):
http://www.mediafire.com/?s69s2uhx40mpljy
http://www.mediafire.com/?9rqz9yvu5bzg8la
http://www.mediafire.com/?okf44t4b13bzd4k

I'm too lazy to listen. Which audio channel is missing, a fds one or a regular one?

Well when I run the rom in FCEUX and disable the FDS audio chanel, it sounds exactly like my Twin Famicom. So I guess the FDS channel is the one missing.

jpx72 wrote:

Well when I run the rom in FCEUX and disable the FDS audio chanel, it sounds exactly like my Twin Famicom. So I guess the FDS channel is the one missing.

If you can find the pinout of the 2c33 chip see if you can find the audio out pin. Tap the pin with a capacitor and see if you get audio. If audio works from the chip you know the missing link is somewhere on the pcb. First you need to find out if the problem is the chip or the pcb.

Well I found the pin #54 of 2C33 that produces the FDS sound. I tried to get the audio there and it worked. So the problem is somewhere in the channel mixer. I have to trace it. Any chance of TwinFamicom schematics?

jpx72 wrote:

Well I found the pin #54 of 2C33 that produces the FDS sound. I tried to get the audio there and it worked. So the problem is somewhere in the channel mixer. I have to trace it. Any chance of TwinFamicom schematics?

Try googling but I wouldn't bother with schematics.  The twin pcb has no masking just follow the circuit and tap it at various points until you find where the audio stops.