HP zx5000 - Manual (Page 127)

5–20 Maintenance and Service Guide
Removal and Replacement Procedures
10. To separate the optical drive from the HP USB Digital Drive
or diskette drive, remove the 4 PM2.0×3.0 screws 1 that
secure the drives together.
11. Separate the drives 2.
Disassembling the Combination Drive
Reverse the above procedure to reassemble and install the
combination drive.