The scanner unit heater is an option and requires installation.
- Remove the left cover (
x7).
 - Raise the ADF
 - Remove the rear scale (
x3).
 - Remove the left cover (
x2).
 - Remove the front āLā cover (cap x1, 
x1,
x 2)
 - Remove the exposure glass.
 - Turn the scanner motor belt to move the 1st scanner carriage from left to right as far as the lens block cover.
 - Position the heater and fasten the right end (
x1).
 - Align the hole of the heater with the hole [A] in the plate.
 - Pass a screwdriver through the hole and fasten the screw [B] (
x1).
 - Pass the heater harness through the hole in the frame [A].
 - Connect the connectors on the right side of the machine [B].