I have a g4 800mhz imac with a Pioneer 104 superdrive installed.
Suddenly the drive will not recognize and mount cd disks of any
kind-cdrs, data cd, dvds. It clicks a little, and after about 30 secs
spits the disks out. Similarly when I try to burn using Toast, it does
not recognize the blank cd inserted. I do not hear the worling sound
of the cd spinning, just some clicks. When I put a disk in, it
appears to have moved a bit when it comes out.

Because of the complexity of the drive assembly into the imac it is
hard to remove.I am not sure if I could remove it I could test it on
another machine. It is also hard for me to see if the laser is
lighting.

I have tried a bit of compressed air, and a radio shack cd cleaning
cd. That cd did not mount and thus I do not think it did anything.

Is there anything to be done except replace the drive.
If I must replace, can I swap in a new Pioneer dvr 106?

Many thanks in advance,
Phil