4-22
BRC-300/300P
BRU-300/300P
Check the connection
of the optional card.
No
Is the fuse
F4002 normal on the
MC board ?
Yes
Connected to the lower card slot.
Connected to the upper card slot.
No
Is the fuse
F4003 normal on the
MC board ?
Yes
Replace the fuse F4003
on the MC board, and
check the power supply
system.
Replace the fuse F4002
on the MC board, and
check the power supply
system.
No
Does
+
12 V exist
in L4301 on the
MC board ?
Yes
MC board failure
(Q4004, Q4005, or the
peripheral circuit)
Replace the defective
parts or the MC board.
One of the following is
defective.
.
Pull-up resistors of pins 5 to 9
and 11 to 13 of IC3518.
.
IC3518 or the peripheral circuit
Check above in order from the
top to identify the defective part.
No
Does
+
12 V exist
in L4302 on the
MC board ?
Yes
No
Is the FFC
between the MC and
CN boards correctly
connected ?
Yes
Connect the FFC
between the MC and
CN boards correctly.
No
Is the FFC
between the MC and
CN boards correctly
connected ?
Yes
MC board failure
(Q4002, Q4003, or the
peripheral circuit)
Replace the defective
parts or the MC board.
Connect the FFC
between the MC and
CN boards correctly.
Is any of pins
5 to 8 levels in IC3518
set to “L” on the
MC board ?
Is any of pins 9, 11
to 13 levels of IC3518
set to “L” on the
MC board ?
No
Check the connection
between the optional
card and the MC board
to identify the defective
part.
No
Check the connection
between the optional
card and the MC board
to identify the defective
part.
Yes
Yes
FFC: Flexible flat cable
c-6
4-4-4. Trouble when Connecting the Optional Card
c-6.
The power indicator lights, but the optional card does not function.