Lcd Display Malfunction - Oki C810 Maintenance Manual

Oki Data CONFIDENTIAL

7.5.2.(1) LCD Display Malfunction

Memo For numbers of (1) through (26) after each connector name, refer to 7.5.2 (18)
"Connection Diagrams".
(1-1) Nothing is displayed in LCD
Confirmation Items
(1-1-1) Confirm fuse
F5 (fuse) of PU PCB Check to see if F5 is blown out.
(1-1-2) Confirm connection systems
Connection between Check to see if the cord from the low-voltage
low voltage power power supply is connected properly to the
POWER connector ⑩ of the PU PCB. Check for
supply unit and PU
PCB
any incomplete connection or skew insertion.
Cord ASSY Check to see if the cord has any wire breakage.
interconnecting the Check to see if the cord has any peel-off of the
low-voltage power covering. Check for any fault in the cord ASSY,
supply unit and the such as dislocated wire, etc.
PU PCB
Connection Check to see if the 7pin FFC is properly plugged
between PU PCB into the
OPE connector ⑰ of the PU PCB. Check to see
and operator panel
PCB (PRP PCB)
if the 7pin FFC is properly plugged into the CN
connector ⑲ of the operator panel PCB (PRP
PCB). Check for any incomplete connection or
skew insertion.
FFC interconnecting Check for wire breakage with a circuit-tester.
the PU PCB and the Also, check visually for peel-off of the covering.
operator panel PCB
(PRP PCB).
FFC interconnecting Check to see if the 12pin FFC is properly
plugged into the CUIF connector ⑨ of the PU
the PU PCB and the
CU PCB.
PCB. Check similarly the CU PCB side also.
44072903TH Rev.1
Confirmation Tasks Action at NG
Replace F5 or
PU PCB.
Redo the
insertion of the
cord properly
Replace the
cord with a
normal one.
Redo the
insertion of the
cord properly.
Replace the
FFC with a
normal one.
Replace the low
voltage power
Supply.
Confirmation Items Confirmation Tasks
(1-1-3) Confirm the power systems
AC power supplied Check the supply voltage of the AC power.
to the printer
Voltage setting of Measure the supplied AC voltage. Check the
low voltage power power supply settings of the printer in use.
supply unit (100V (Check the shortcircuit plug designed for
system/230V switching of low-voltage power setting. Short-
system) circuit plug provided/not provided = 100V
system/230V system.)
5V power supplied Check the 5V power at pin 7 of the POWER
connector ⑩ of the PU PCB.
to the PU PCB
5V power supplied Check the 5V power at pin 5 of the CN
to the operator connector of the operator panel PCB (PRP
panel PCB (PRP PCB).
PCB)
(1-1-4) Confirm the power short
5V power and 24V Check for short-circuiting through the POWER
connector ⑩ of the PU PCB.
power supplied to
the PU PCB
4, 5, 6 pin: 24V
7 pin: 5V
8 pin: 0VL
1, 2, 3 pin: 0VP
If there is any short-circuiting, locate it by
isolation.
Unplug the cords connected to the PU PCB,
one by one, and locate the short-circuited part.
7. TROUBLESHOOTING PROCEFRURES
Action at NG
Supply AC
power.
Set the low-
voltage power
setting to the
proper values.
Replace the low
voltage power
supply.
Replace the F5
or PU PCB.
Replace the
short circuited
part.
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