I have an LD-V4300D, I have a problem on NTSC audio discs the right channel doesn't work and the left channel is a bit distorted. With disc Pal the left and right channels work fine. From the Service manual I can think that the problem could be the IC302 demodulator where could I look for the problem?
Thanks to whoever can help me.

If the NTSC disc has AC-3 encoded then you’ll get noise on the right channel and the left channel could be mono soundtrack, commentary, or whatever was put on it. You need a player that will play the digital sound to get the movie soundtrack.

The tested discs are all ntsc stereo analog, tested on other ld-v4300 work well the two channels