alternator working then not working!!!!

When i was driving to work the other day in my landy i noticed that the battery gauge was showing it was losing power....when i got to work i revved it to see if it would charge no luck..when i was driving home it was the same but then power was going back into the battery so i thought there could have bin issues with the battery so i went an bought a new one. It all seemed fine but 3 days later same thing has occured there is power though the alternator an then there is not, i have had a multimeter on it an thats what is shown.

Could this mean a whole new alternator or could there be somthing else i could do to help??

thanks luke :doh:

Check all your earths first...and contacts on the alternator.

what voltage output are you getting from the alternator.u should get somewhere around 14.4v,thats what mine is

alt. brushes / dicky regulator unit?