Oki Data CONFIDENTIAL
45487001TH Rev.1
6-31 /
6. Troubleshooting procedure
6.5.2 (1) LCD display error
Memo For the numbers from
to
after the name of the respective connectors,
refer to section 6.5.2 (18) “Wiring diagram”.
(1-1) LCD does not display anything.
Check item Check work
Actions to be taken
at NG
(1-1-1) Check the fuse.
Fuse of the PU/CU
board
Check if F3 or F5 has blown out. Replace the PU/
CU board.
(1-1-2) Check the system connection
Connection
between the low
voltage power
supply unit and the
PU/CU board
Check if the cable from the low voltage power
supply to the POWER connector
of the PU/
CU board is normally connected or not.
Check if the connector is connected only in
the half-way or not, and check if the connector
is inserted in slanted angle or not.
Re-connect the
cable normally.
Cable assembly
connecting the
low voltage power
supply unit and the
PU/CU board
Check if the cable is half-open circuit.
Check if sheath of the cable has not peeled
off or not.
Check if the cable assembly is defective such
as internal wires are disconnected or not.
Replace the
cable with the
normal cable.
Connection
between the PU/
CU board and the
control panel board
Check if the 10-conductor FFC is connected
to the OPE connector
of the PU/CU board
normally or not.
Check if the 10-conductor FFC is connected
to the OPE connector
of the control panel
board normally or not.
Check if the connector is connected in the
halfway only or not, and check if the connector
is inserted in a slanted angle or not.
Re-connect the
cable normally.
FFC connecting the
PU/CU board and
the control panel
board
Check if the cable has open circuit or not with
VOM. Check if sheath of the cable has not
peeled off or not by visual inspection.
Replace the
FFC with the
normal FFC.
Check item Check work
Actions to be taken
at NG
(1-1-3) Check the peripherals of the power supplies
AC power that is
supplied to the printer
Check the supplied voltage of the AC power
source.
Supply the AC
power.
5V power that is
supplied to the PU/
CU board
Check for 5V power supply at pin-1, -3 and
-4 of the POWER connector
of the PU/CU
board.
Replace the low
voltage power
supply unit.
3.3V power that is
supplied to the PU/
CU board
Check for 3.3V power supply at pin-22 of the
POWER connector
of the of the PU/CU
board.
Replace the low
voltage power
supply unit.
3.3V power that
is supplied to the
control panel board
Check for 3.3V power supply at pin-4 of the
OPE connector
of the control panel board.
Replace the PU/
CU board.
(1-1-4) Check that power supply circuit has no short-circuit.
5V power and 24V
power that are
supplied to the PU/
CU board.
Check that power supply circuit has no short-
circuit at the POWER connector
of the PU/
CU board. The follow voltage must appear
respectively.
pin-11, -13, -14, -15, -16: 24V
pin-1, -2, -3, -4: 5V
pin-5, -6, -7, -8, -9: 0VL
pin-17, -18, -19, -20, -21: 0VP
pin-10: 5Vs
If any voltage does not appear and short-
circuit is detected, locate the source of the
short-circuit as follows:
Disconnect the cables that are connected to
the PU/CU board one cable after another until
location of the short-circuit is found out.
Replace the part
causing short-
circuit.
(1-1-5) LSI operation check
I/F signal supplied
from the PU/CU
board to the control
panel board.
Check if signals are output to the OPE
connector
of the PU/CU board.
Pin-5: Send data (Sending data from the PU/
CU board)
Replace the PU/
CU board.
I/F signal supplied
from the PU/CU
board to the control
panel board.
Check if signals are output to the OPE
connector
of the PU/CU board.
Pin-7: Send data (Sending data from the PU/
CU board)
If it is normal, signals are output always.
Replace the
control panel
board.
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