Editing Amstrad CPC 664 Maintenance Guide (section)

=== Worm drive / stepper lubrication ===

The stepper motor moves the head radially across the disc via a fine-pitch worm-drive lead screw. The worm drive needs '''light machine oil''' (e.g. clock oil or sewing-machine oil) every 5&ndash;10 years. Symptom of dried lubrication: stepper makes a chattering sound and the head fails to seek properly, often reporting "Track 0 error" or "Disk error" when accessing a known-good disc.

Procedure:
# Remove the drive's top cover.
# Locate the worm drive (a 2&ndash;3 mm-diameter threaded brass rod connecting the stepper motor to the head carriage).
# Apply a single drop of clock oil to the lead screw at the head carriage end and the stepper end.
# Move the head fully in and out by hand a few times to distribute the oil.
# Avoid getting oil on the head itself or on any belt or pulley.