I have new looking Sony Walkman WM-FX999 It plays like new thanks to a new belt from Marian. The side A plays fine but the right channel is alot quieter than left channel. I can hear almost mumbling sound too only on the right channel. Side B is perfect. I presume Side A and B would use the same audio circuitry on the board. thanks
Yes and no. All Autoreverse Walkman I have seen use a 4 track head so the signal path for side A and B will be different around the heads. It is also possible that there is a problem with the tape path, for example something causing the tape to not touch the head properly on just one side. The mumbling you hear could be a trace of Side B being played backwards.
I see what you mean http://www.flickriver.com/photos/saka_matra_miscellaneous/10513102074/ according to that only four Walkmans ever used that arrangement. It actually makes it more likely that one head of the two heads is out of alignment. With a normal four track single head Walkman at least you know that the spacing between the tracks is going to be correct. With this one I presume there must be azimuth adjustments for each of the two heads, and you could have one direction set perfectly and the other direction way out.