It`ll be a dirty audio control head. Google...images and `vcr audio control head` to see where it is located. It`s to the right of the main video head drum..(dont scrub at the video head drum, the chrome wheel in the centre as the video heads are very delicate and easily broken whereas the audio control head is like the old cassette type assembly and not easily damaged at all).It`s easy to get at with a clean cloth and a slight dab of head cleaner fluid,(isopropyl alcohol).Wrap the cloth around your finger... an old cloth handkerchief is ideal material for this..and rub the audio control head mainly at the bottom end and that should do the trick for you.VCR only records VISION. There is no SOUND. I have cleaned it with a cleaning tape, thinking that this would fix the problem, but no luck. Can anyone help?
Also check other end of scart into tv is also inserted fullyCheck scart at back is fully in as partly in can cause picture but no sound and vice versa