To see the hard drive mechanism while it's working

, I made a new transparent cover, with the top in plexyglass, taking that from an hold broken hdd. Then I have replaced the cover of my working hard disk (MAXTOR 6L080L0 - DiamondMax10 - BAJ41G20) with the new transparent one.
I did the swap in a very short time, to reduce the probability that the dust goes inside. Then I have used the HDD normally.
The day after, the hard disk became crazy (and me too!): the heads have gone to hit repeatedly to the center! I have disconnected it. When I have tried to reconnect it again, the hdd has stopped clicking, but it is not working now! The BIOS recognise it, but it takes a long time to do it; the motor spins, the heads moves slowly from the inner track to the outer one (recalibration?), and then they stay there.
What kind of damage I have done?
Thanks to alll you Guru!
Carlitos
PS: now I have ordered one Raptor X
http://www.wdraptorx.com 