Brother LX-300 Service Manual page 171

14
Cartridge size, film type cannot be detected correctly.
a. Defective cartridge type detector (CSIZE4) switch.
b. Defective cartridge type detector (CSIZE3) switch.
Problem
a. Defective Is the yellow lead connector
cartridge type connected to CN7 on the
detector main PCB?
(CSIZE4)
Is the cartridge leaf switch
switch
CSIZE4 pressed when an
A4 cartridge is inserted?
Is the cartridge leaf switch
CSIZE4 not pressed when
an A4 cartridge is inserted?
Is the cartridge leaf switch
CSIZE4 not pressed when
an A6 cartridge is inserted?
Is main CPU port P20 (Pin
8) at High level when leaf
switch CSIZE4 is open?
When leaf switch CSIZE4 is
shorted, is CN7 on the Main
PCB shorted?
Is main CPU port P20 (Pin
8) at Low level when CN7
on the Main PCB is
shorted?
When main CPU port P20
(Pin 8) is at Low level, is
this recognized by the main
CPU?
Check Item
Leaf switch assy not
connected.
Incorrectly installed
leaf switch assy.
Incorrectly inserted
cartridge?
Incorrectly installed
leaf switch assy.
Conductivity problem
in Main PCB.
Defective pull-up
resistor R61.
Defective leaf switch
assy.
Conductivity problem
in Main PCB.
Defective series
resistor R65.
Defective main
CPU#3.
Cause Remedy
Correctly connect
the leaf switch assy.
Correctly install the
leaf switch assy.
Re-insert the
cartridge.
Correctly install the
leaf switch assy.
Replace Main PCB
assy.
Replace Main PCB
assy.
Replace leaf switch
C4 assy.
Replace Main PCB
assy.
Replace Main PCB
assy.
Replace Main PCB
assy.
7-21
See
Repair
Section
3.3.3
3.3.4
3.3.5
3.3.1
3.3.3
3.3.4
3.3.5
3.4
3.17
6.2
3.3.1
3.3.3
3.3.4
3.3.5
3.4
3.17
3.3.3
3.3.4
3.3.5
3.4.2
Replace R61.
3.5.1
3.3.1
3.3.3
3.3.4
3.3.5
3.4
3.17
3.3.3
Replace R65.
3.3.4
3.3.5
Replace
3.4.2
CPU#3.
3.5.1