Pro 7900 and 9900 Field Repair Guide 10/6/10
Carriage Release (Manual) Printer Component, Software Item, LCD Display, Printer Button Page 390.
3. Rotate the White Gear counter clockwise to unlock the Carriage.
Rotate the White Gear counter clockwise until the Carriage is un-locked.
Condition 1 - Carriage Locked.
Condition 2 - Carriage Un- Locked.