I did a swap from a US Duo to a JP Duo with the M5205 chip. Both systems retained the same behavior (US Duo no ADPCM, JP Duo has ADPCM but fading audio). The JP Duo hasn't had a cap swap yet so that is why the fading audio is there. As I stated both systems behaved exactly the same. So I am beginning to suspect another part. What about the other IC's near this area? I know one of them is the opamp, what os the IC between Opamp and the M5205 chip? It is directly above the voltage regulators, long skinny IC.