[C320-list] Alternator for Perkins M30

[dmcnamara3 at woh.rr.com]

Hello,
I have a 1994 (hull 64) Catalina 320 with a Perkins m30 diesel.  It appears that the alternator has gone out. It is a Lucas Marine A-127-55MT  I have looked throught the archives for what people are replacing it with but have not found a difinitive source or model.  I realize I should upgrade to a more efficent system but for now I just want to replace what I have with out making it into a project.  Is there a good replacement that is US sourced? 
Any help would be greatly appreciated.  By the way, I am about 99% sure it is the alternator, when the engine is running (above idle) the volt meter at the helm shows 12.6 volts, the charge light is on and when I put a multimeter on the alternator itself with the engine running it shows 12.6 volts.    
Thanks again,
Dan
Sandusky, Ohio