There is no voice when I replayed the camcorders

Question

I have a Sony DCR-TRV22 camcorders and it works great until last September. After recording some events, I usually rewind and replay the tape. However, there isn't any sound coming out. Sometimes the voice will come out for a short period of time, then it starts breaking up and ends up without voice at all. I bought a tape cleaner and it's still giving the same result. ANY SUGGESTION PLEASE..! Thank you very much.