HP LASERJET 3600 - Manual (Page 5)

8. Remove the main drive assembly (MDA). There are six screws attaching the MDA to the
chassis. Carefully note the locations of the screws to be removed.
CAUTION: Removing the incorrect screws could lead to opening up the
MDA, requiring a unit replacement!
NOTE: Two gears may fall off, there are instructions in step 16 on how to
align them during the re-installation process.