I have read that perhaps a bad batch of transformers were used
although this
is just someone's opinion and may not be correct. People have
contacted CA
about the problem and some sugestions were given, but they did not
work.
(don't know what they were) Another solution is to replace the power
supply
unit. It may be possible to do this yourself although you need to
indentify
that it is the power supply causing the problem. This is probably a
job for a technician. Here is a link to a discussion from owners of
the 640c with noise
problems.
http://forum.ecoustics.com/bbs/messages/1/75555.html

dezza.

Interesting comments!
Thanks for providing the link.
(In t he forum the person talking about 'tiny ticks while the cd spins'
corresponds to what seems to happen with my cdplayer)
Indeed, the Pwer Supplies problem it seems to point in that direction.