Audio problem on luxor tv

[Pjaska]

Hello, i have weird problem in my luxor 3384 if i connect game console for it with composite cable via scart adapter the audio works fine, if i connect with 'retro gaming cables' rgb cable then audio dosnt work. If i use rgb cable to any other tv it works fine but luxor is silent. With same console composite cable audio works fine. How is it even possible? Electronics are sometimes so mysterious. Any ideas?