alternator

Ok,
Fitted new alternator after last one fell to bits. All was fine for couple of months then heading down M5 & rev counter started to die and battery warning light came on. So new alternator is not charging battery, connections on alternator look fine as do the ones on the battery - so what else do i check (i do have a circuit tester though not sure how to use it) any help would be greatly appreciated as bank balance cringes at the thought of sticking her in a garage for diagnostics and repairs. Shes an M reg 2.5 tdi
Cheers in advance
Simon

Bushes brushes inside the alternator, take it off and see if they worn. Hope that is of help its what I used to do with my mini and its the same stuff just bigger.

Cheers for that, alt brand new, did check tho and all a ok inside.