Symptoms of dying CD drive?

I have one of the popular ASUS 24X RW CD drives that has probably
died. I'll replace it when I can afford to bring my machine down, but
meanwhile I would appreciate knowing the typical symptoms of a CD drive
mechanical failure and what troubleshooting procedures would detect a
mechanically failing drive.

In the case of my ASUS, when I first installed it, when playing an audio
CD, there was about a one second pause in sound a second or two after
the start. Annoying, but I lived with it for half a year. Now, however,
the drive does not function at all.

When I insert an audio CD, Audacious says "No audio capable CD drive
found". This accompanied by noises that sound like the head moving back
and forth and then a speedup of the drive motor that sounds like a
hot-rodder taking off from a red light.

I insert a DVD movie in and do

$ mplayer dvd:://1 -dvd-device /dev/sr0
Warning unknown option include at line 177
...
mplayer: could not connect to socket
mplayer: No such file or directory

I tried:

# dd if=/dev/sr0 of=/nev/null bs=1048
dd: opening `/dev/sr0': No medium found

I could not mount a data cdrom:

# mount /dev/sr0 /media/cdrom
mount: no medium found on /dev/sr0

Haines Brown