alternator squeals with new bearings. What else?

[Konstantin Bogach]

I replaced both bearings and it still squeals.  I reduced belt tention
and it seems made it quieter but still disturbing.
I always tried to keep tention such so it could move about 10mm under
thumb pressure.  Maybe it is to tight for alternator?
Can anything else give that squealing sound?

Thanks.
Konstantin.
200tq '89
200tqa '89
S4 '93