Brother mfc-3420c Service Manual page 5

CHAPTER 4 DISASSEMBLY/REASSEMBLY AND LUBRICATION
This chapter details procedures for disassembling and reassembling the machine together with
related notes. The disassembly order flow provided enables you to see at a glance the quickest
way to get to component(s) involved.
At the start of a disassembly job, you check a disassembly order flow that guides you through a
shortcut to the object components.
This chapter also covers screw tightening torques and lubrication points to which the specified
lubricants should be applied during reassembly jobs.
4.1 DISASSEMBLY/REASSEMBLY..................................................................................4-1
n Safety Precautions ...................................................................................................4-1
Tightening Torque List .................................................................................................4-2
n Preparation...............................................................................................................4-4
n How to Access the Object Component......................................................................4-4
n Disassembly Order Flow...........................................................................................4-5
4.1.1 Print Head Unit.................................................................................................4-6
4.1.2 ADF Document Support and ADF Cover ........................................................4-12
4.1.3 ADF Components on the Upper ADF Chute ...................................................4-13
4.1.4 ADF Components on the Lower ADF Chute ...................................................4-17
4.1.5 Rear Cover ....................................................................................................4-23
4.1.6 Document Cover and Document Pressure Rollers 2.......................................4-24
4.1.7 Scanner Cover (Scanner Unit)........................................................................4-26
4.1.8 Scanner Open Sensor Actuator and Control Panel ASSY...............................4-29
4.1.9 Main Cover and Front Cover*.........................................................................4-31
4.1.10 Main PCB, SDAA PCB*, and Media Module*..................................................4-32
4.1.11 Auto Sheet Feeder (ASF) ...............................................................................4-39
4.1.12 Driver PCB with Registration Sensor PCB......................................................4-42
4.1.13 Rear Support Plate, NCU/PS Shield Box, Power Supply PCB, MJ PCB*
and NCU PCB** .............................................................................................4-45
4.1.14 RH Support Plate and Purge Unit ...................................................................4-52
4.1.15 Encoder Strip .................................................................................................4-55
4.1.16 Carriage Rail, Carriage, and Carriage PCB ....................................................4-56
4.1.17 Sensor Support (Ink Empty Sensor PCB) and Star Wheel Support.................4-59
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