Alternator Pully Problem [/align][hr]

My 2003 TDI 130 seems to be having a slight problem.
The groved belt that pulls on the alternator seems to be jumping causing the belt to go slightly slack when it has passed over the alternator pulley. A freind suggested the alternator pully may be seized. Are these a fixed or inertia engaging pully. Suggestions welcome.[/align]

 

hmmm its a fixed single serpentine belt but you might have a bad tensioner or an alignment problem with the pulleys

 

Thanks Dave.
The pulley's seem to be in line it seems to me like a bearing breaking down/grinding in either the pulley or the alternator, its hard to tell which!This is causing the belt to almost jump over the alternator pulley.

 

remove the belt and check for movement in the pulleys ( there should be none ) apart from rotation of course