AAZ has twittering noise - alternator?

[the_old_diver]

Hello again,
My 96 Passat TD (AAZ engine) has a twittering or squeaking noise from somewhere near the alternator when starting from cold, coupled with a rev counter that doesn't go above about 200 rpm regardless of engine speed. After maybe 15 seconds of holding the revs at (by ear) 1200 rpm the squeaking stops, the rev counter needle swings into life and the revs go up to maybe 1600. After that, things are "ops normal" until the next cold start.

Can anyone tell me what is going on under the lid?

Thanks in advance, OD

PS car has only done 214k...

[the_old_diver]

This little problem resolved itself today when the rev counter died, the battery light came on and the engine temperature went up to 110.
The alternator belt looked fine two days ago but all that remained today was just a couple of rubber threads. A new belt has sorted it out.
My only grumble is that it seems you cannot replace the alternator belt without first removing the hydraulic pump belt, which turned a 10 minute job into a 40 minute one.
Cheers, OD