I identified the source of the whine (changed power steering pump twice, since noise was detected with stehoscope on pump - but never checked AC compressor) finally as coming from the AC compressor.
a) what is involved in changing the compressor (aside from refilling/charging the AC system)? Any major parts to be removed? Good DIY write ups available?
b) can the compressor whine be fixed (with a repair kit for example) once it is out? If not: recommended replacement? Junk yard or ebay used one? No name refurb? Sources?