Violent Storm sound problem

[Sakuragi]

Hello everyone !
I was enjoying my Violent Storm when suddenly all sound disappear . I have rebooted the pcb, everything was ok on the test screen but still no sound. I went to the system menu and put the sound level to 11 to 30, now i have a muffled sound in mono and a bit better in stereo but parasited. I can't enjoy the amazing sound of this game like before

Do you think it could be the Power IC from Sanyo more than the Konam'is custom sound chip ? I have tried to find some LA 4705 3D3 on the web but can't find one, do you think another LA 4705 XXX model could do the job instead of the 3D3 ?

No problem with other pcb of my collection

Thank you in advance for any help !

[Asayuki]

Check for loose joints, like tap on the board when it's supposed to be generating sound.
If you have a mechanical volume pot then try adjusting/replacing it.
Also ensure that +12V and -5V are both present and stable (under load a DC measure gives the intended voltage, an AC measure gives zero).
If anything fails, your first suspect should be the power amp instead of some custom chip. The marking code "3D3" indicates random stuff like year and place of manufacture, so yes you can go with any LA4705.
I hope this helps.

[Sakuragi]

Everything is fine with voltage, I will try to replace the LA 4705 and some capacitors. Thank you Asayuki

[PunkicCyborg]

The Konami custom sound ID probably failed due to leaking capacitors. They can be repaired but probably want to leave it to a pro since the IC is ceramic and pretty delicate. I believe Caius does these repairs in Europe

[caius]

The Konami custom sound ID probably failed due to leaking capacitors. They can be repaired but probably want to leave it to a pro since the IC is ceramic and pretty delicate. I believe Caius does these repairs in Europe

Confirmed.The problem is most likely in the '054986A' audio module, judging from sudden loss of sound I think the problem is the 4558 OP-AMP in the underneath more than capacitors.Just today I fixed a Moo Mesa PCB with same issue and in the last days I fully serviced five '054986A' modules in a row, all of them had a bad 4558 OP-AMP and someone also a bad AD1868 DAC.