Lcd Display Trouble; Lcd Displays Nothing - Oki MC362w Maintenance Manual

Oki Data CONFIDENTIAL

7.5.5.(1) LCD Display Trouble

(1-1) LCD displays nothing

Check item
(1-1-1) Checking fuse
Fuse on SU board Check whether F1 or F5 has
blown.
(1-1-2) Checking connections
Connection between low- Make sure the low-voltage power
voltage power supply unit and supply unit is connected to the
SU board POWER connector on the SU
board properly.
Cable assembly connecting
Check whether the cable connector
low-voltage power supply unit
is half-connected or tilted, or
to SU board
whether wires are broken.
Check whether there is any fault in
the cable assembly, e.g., missing
wires.
Connection between SU Make sure the 16-pin FFC is
board and operation panel connected to the OPE connector
on the SU board properly.
Make sure the 16-pin FFC is
connected to the CN1 connector
on the OPE board properly.
Check whether the cable connector
is half-connected or tilted.
FFC connecting SU board to Check for broken wires using a
OPE board tester.
Check visually whether the sheath
peels.
Connection between SU Make sure the 45, 46, 47-pin FFC is
board and CU/PU board connected to the PDLIF connector
on the SU board properly.
Make sure the 4, 5, 6-pin FFC is
connected to the MFPIF connector
on the CU/PU board properly.
Check whether the cable connector
is half-connected or tilted.
44952001TH Rev.2
Checking method Action in case of NG
Replace F1 or F5 or SU
board.
Connect the cable
properly.
Replace the cable with
a good cable.
Connect the cable
properly.
Replace the cable with
a good cable.
Connect the cable
properly.
Check item Checking method
FFC connecting SU board to Check for broken wires using a
OPE board tester.
Check visually whether the sheath
peels.
(1-1-3) Checking power supplies
AC power supplied to the Check the supplied voltage from
printer the AC power source.
5V power supplied to SU Check the 5V power at 3, 4pin of
board the POWER connector on the SU
board.
3.3V power supplied to OPE Check the 3.3V power at 14pin of
board the CN1 connector on the OPE
board.
(1-1-4) Checking for short circuit of power supply
5V and 24V power supplied to Check for a short circuit using
SU board the POWER connector on the SU
board.
7, 8pin: 24V
3, 4pin: 5V
5, 6pin: 0VL
9, 10pin: 0VP
If there is a short circuit, locate it.
Disconnect the cables from the
SU board one by one to locate
the short circuit.
(1-1-5) Checking LSI operation
I/F signal from SU board to Check whether signals are output
OPE board to the OPE connector on the SU
board.
9pin: Transmission data (sent
from the SU board)
11pin: Clock
13pin: Enabling
15pin: Reset
Signals should be always output
under normal conditions.
7. TROUBLESHOOTING PROCEDURES
Action in case of NG
Replace the cable with
a good cable.
Supply AC power.
Replace the low-voltage
power supply.
Replace the SU board.
Replace the short-
circuited component.
Replace the SU board.
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