The clicking sound is made by the laser eye moving up and down, failing to get a sharp focus on the disc.
Originally Posted by Antoniomike7
The disc needs to be cleaned, the laser might need to be cleaned, and/or the laser needs to be replaced.
@Dreamwebber : The slimlines (Other than the SCPH-70000 series) have the best lasers - compared to the FAT PS2s.
Unmodified SCPH-77006 with SM 3.6
SCPH-39006 with M-chip modchip, SCPH-10281 NA and refurb Seagate 80GB HDD
SCPH-10000 v1.00 with SCPH-10190 PCMCIA NA and SCPH-20400 HDD unit