the D/A converter is blown... I fixed this problem on diferent kinds of PS2, more than once. Also there's a few transistors on the output after the D/A which can blow also.
This happens because the owner connected the PS2 to a stereo and it had a diference of potential to the PS2 or the TV, which caused a ESD discharge on the audio connector. If you think about it the right way to connect the PS2 to anything is 1st hook the A/V cable to the system and then finally connect the cable to the PS2. The last thing you connect is the PS2 power cable.
SCPH-10000_GH-001 SCPH-15000_GH-003 SCPH-18000_GH-008 SCPH-30001_GH-005 SCPH-30000_GH-016(V4) SCPH-30001_GH-010(V4)
2xSCPH-10190, 2xSCPH-10350, 2xSCPH-10280
"**** j0 hackers!"
-Sjeep (As seen on TOXIC OS ELF...)