Brother LX-300 Service Manual page 168

11
No cutting in Y direction.
a. DefectiveTrimmer Position Switch (SG-SW).
b. Abnormal Y-cutter vertical movement.
Problem
a. Defective Is the blue lead connector
Trimmer connected to CN5 on the
Position Switch Main PCB?
(SG SW)
Is main CPU port P15 (Pin
22) at High level when leaf
switch SG assy is open?
When leaf switch SG assy
is shorted, is CN5 on the
Main PCB shorted?
Is main CPU port P15 (Pin
22) at Low level when CN5
on the Main PCB is
shorted?
When main CPU port P15
(Pin 22) is at Low level, is
this recognized by the main
CPU?
b. Abnormal Y- Does the Y-diversion lever
cutter vertical rotate when the control cam
movement gear rotates?
Is Y-cutter assy mounted
correctly?
Check Item
Leaf switch assy not
connected correctly.
Conductivity problem
in Main PCB.
Defective pull-up
resistor R48.
Defective leaf switch
assy.
Conductivity problem
in Main PCB.
Defective series
resistor R44.
Defective main
CPU#3.
Y-extension springs
incorrectly installed.
Foreign matter under
the Y-diversion lever
Incorrectly mounted Y-
cutter assy.
Cause Remedy
Correctly connect
the leaf-switch assy.
Replace Main PCB
assy.
Replace Main PCB
assy.
Replace leaf switch
SG assy.
Replace Main PCB
assy.
Replace Main PCB
assy.
Replace Main PCB
assy.
Correctly install
Y-extension springs.
Clean out foreign
matter.
Mount the Y-cutter
assy correctly.
7-18
See
Repair
Section
3.3.3
3.3.4
3.3.5
3.3.3
3.3.4
3.3.5
Replace R48.
3.4.2
3.5.1
3.3.1
3.3.3
3.3.4
3.3.5
3.4
3.12.1
3.3.3
Replace R44.
3.3.4
3.3.5
Replace
3.4.2
CPU#3.
3.5.1
3.3.1
3.3.3
3.3.4
3.3.5
3.4
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