Did you remember to de-solder the two blobs that short out the laser coils?
All new laser units are shipped with shorts in place to protect the units from static. These must be removed before the laser is mounted in the drive.
Main: 861v4 (LPS),800v4,HD621,DSP6k,DSP5200HC,DSP5k,C15,Apple TV,Sky HD,Cambridge Audio BD
Office: 818v3,800v3,504,557,MF MC2s,Mac Mini