KHS-400A (SCPH-10000 to SCPH18000)
KHS-400B (SCPH-30000 to SCPH30000R)
KHS-400C (SCPH-39000, some models do use a newer version laser. they're refered as V7)
All lasers are eletrically compatible, but their mechanical characteristics are diferent, so you are likely to replace it with the same version it was before ...
Still you can use B series lasers on machines with a original A series laser without big trouble.
To use a V1 laser in a V7 machine like the woore said, I think he had to change the V7 drive mechanism for a V4 and probably he had to glue a plastic somewhere in the laser so it could reach the limiter switch.
SCPH-10000_GH-001 SCPH-15000_GH-003 SCPH-18000_GH-008 SCPH-30001_GH-005 SCPH-30000_GH-016(V4) SCPH-30001_GH-010(V4)
2xSCPH-10190, 2xSCPH-10350, 2xSCPH-10280
"**** j0 hackers!"
-Sjeep (As seen on TOXIC OS ELF...)