Brother LX-200 Service Manual page 169

9
Document width cannot be detected correctly.
a. Defective Y-carriage (Y-CA) motor.
b. Defective sensor unit (YCA-F).
c. Defective Y-cutter arm.
Problem
a. Defective Y- Is the Y-CA motor harness
carriage (Y-CA) connected to connector C11
motor on the Main PCB?
Are pulses output from output
ports P00 to P03 (Pin 9 to
Pin 12) of the main CPU#1?
When the output from output
ports P00 to P03 (Pin 9 to
Pin 12) of the main CPU#1 is
High, is the output from
transistor array QA3 Low?
When output port P65 (Pin
61) of the main CPU#1 is
High (equal or more than 4V),
is +24V DC applied to Pin 5
of connector CN11?
Correct resistance value
(approx. 227 ohms) between
each phase of the Y-CA
motor and the COM pin?
b. Defective Is the flat cable connected to
sensor unit connector CN2 (CN14) on
(YCA-F). the Main PCB?
Sensor lever cuts
photosensor when a
document is inserted?
Photosensor cut off when no
document is inserted?
Is photosensor PH2 on the
Paper size detector PCB
working correctly?
Normal continuity in Paper
size detector PCB flat cable?
c. Defective Y- Does the Y-cutter arm move
cutter arm when the Y-CA motor
rotates?
Y-cutter arm is caught during
its movement?
Is the Y-cutter arm separated
from the sensor frame?
Check Item
Motor harness not
connected.
Defective main CPU#1.
Defective transistor
array QA3.
Defective transistor Q4.
Defective transistor Q3.
Continuity problem in
Main PCB.
Defective Y-CA motor.
Defective connection of
the flat cable.
Sensor lever incorrectly
installed.
Defective sensor lever.
Defective photosensor
PH2.
Discontinuity in flat
cable.
Y-cutter arm and timing
belt incorrectly
installed.
Foreign matter stuck to
the sensor arm.
The Y-cutter arm shaft
is incorrectly installed.
7-17
Cause Remedy
Correctly connect the
motor harness.
Replace Main PCB
assy.
Replace Main PCB
assy.
Replace Main PCB
assy.
Replace Main PCB
assy.
Replace Main PCB
assy.
Replace the Y-CA
motor.
Correctly connect the
flat cable.
Correctly install the
sensor lever.
Replace the sensor
lever.
Replace the Paper
size detector PCB.
Replace the Paper
size detector PCB.
Correctly install the
timing belt.
Clean off the foreign
matter.
Correctly install the
Y-cutter arm shaft.
See
Repair
Section
3.3.3
3.3.4
3.3.5
Replace
CPU#1.
Replace QA3.
Replace Q4. 3.3.3
3.3.4
3.3.5
3.5.1
Replace Q3.
3.3.1
3.3.3
3.3.4
3.3.5
3.4
3.7
3.3.3
3.3.4
3.3.5
3.3.3
3.3.4
Replace PH2.
3.3.5
3.8
Replace the
sensor
harness
550X4.
3.3.3
3.3.4
3.3.5