how can I fix my casset am pm tape radio?

the battery work and the tape turns, but there is no sound or volum. It is a Sony Walkman wm-fx423fm/am. Its automatic reverse. I dont get any sound from either the tape or the radio, Iv tried new batterys but get nothing. I cant fid one like it that I can afford it. Im in a powerchair so I need one that can be cliped on to my pants.There is a # on the back-3-383-081-01. I hope someone can help me. thank you alice