Hi Rudy
I had a similar problem on my BM8000. When I opened up the front, I found a broken rubber "O" ring hanging from one of the ribbon cables. This O ring was part of the volume wheel assembly. The assembly was fairly easy to take apart, the O ring was refitted and I used some high viscosity grease to damp the motion. Since then, everything has worked fine. Should be fairly easy for you to fix.
Regards
Geoff