Philips Norelco 7340 Mens Electric Rechargeable Shaving System Trimmer "head noises causes" Questions

...since I noticed it, it is starting to bother me.. Thanks in advance! Jason you need to bring the head unit and the bassbox back to bose for service or repair, it is aproblem with the powering up

I have a norelco 7340xl that makes an aweful noise when i turn it on to shave. what could be the cause of the noise? it was fine one minute then making noise the next. I replace the heads last ...