There are two ways to refresh the CVS Repositories view in order to see the current connection status of all repositories:
Note: Refreshing the CVS Repositories view may change the resources displayed by the view but does not change the branch and version tags known to the view. Refreshing the tags is discussed in Discovering branch and version tags

  Team programming with CVS
  CVS Repositories 

  Creating a CVS repository location
  Discarding a CVS repository location 
  Discovering branch and version tags