44015503TH Rev. 1
180 /
Oki Data CONFIDENTIAL
7. TROUBLESHOOTING PROCEDURE
7.5.2.(1) LCD display error
Memo For the numbers from to after the name of the respective connectors,
refer to section 7.5.2 (19) “Wiring diagram”.
(1-1)
LCD does not display anything.
Check item Check work
Action to be taken
at NG
(1-1-1) Check the fuse.
F2 (fuse) of the PU
board
Check if F2 has blown out or not. Replace F2 or
the PU board.
(1-1-2) Check the system connection
Connection between
the low voltage
power supply unit
and the PU or CU
board.
Check if the cable from the low voltage power
supply to the POWER connector
of the PU
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 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.
Note!
Connection between
the PU board and
Operator Panel
Check if the 10-conductor FFC is connected to
the OPE connector
of the PU board normally
or not.
Check if the 10-conductor FFC is connected to
the OPE connector of the PU board normally
or not.
Check if the connector is connected in the half-
way 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 board and
the Operator 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.
FFC connecting the
PU board and the
CU board
Check if the 16-conductor FFC is connected to
the CU IF connector of the PU board normally
or not. Check the CU board side in the same
way.
Replace the low
voltage power
supply.
Note!
Note! If the PU board, the CU board and the low
voltage power unit are connected one another
differently from the picture given below, it is
regarded as an abnormal, and the output
from the low voltage power unit stops.
W
hen the output from the low voltage power
unit stops, turn off the power switch, wait
about one minute, and then turn on the power
switch, otherwise, the alarm condition of the
stoppage of the power output is not cleared.
CU board
low voltage power unit
PU board
Check item Check work
Action to be taken
at NG
(1-1-3) Check the peripherals of the power supplies
Pr
imary AC power
source that is
connected to the
printer.
Check the supplied voltage of the AC power
source.
Supply the AC
power.
Voltage setting of
the lower voltage
power supply unit
(100
V system/230V
system)
Measure the AC voltage supplied.
Check the power voltage setting of the
equipment in use.
(Check the shorting plug that is used for
selection of the voltage power supplies.)
Shorting plug is Used/Not used = 100V system/
230V system.
Set the low
voltage power
supply setting.
5V power that is
supplied to the PU
board.
Check for the 5V power supply at pin-7 of the
POWER connector of the PU board.
Replace the low
voltage power
supply.
3.3V power that
is supplied to the
Operator Panel.
Chec
k for the 3.3V power supply at pin-10 of the
CN connector of the Operator Panel board.
Replace F2 or
the PU board.
(1-1-4) Check that power supply circuit has no short-circuit.
5
V power and 24V
power that are
supplied to the PU
board.
Check that power supply circuit has no short-
circuit at the POWER connector no. 10 of the
PU board. The follow voltage must appear
respectively.
pins-4, 5 and 6:
24V
pin-7:
5V
pin-8: 0VL
pins-1, 2 and 3: 0VP
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 board one cable after another until location
of the short-circuit is found out.
Replace the part
causing short-
circuit.
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