Lcd Display Trouble; Lcd Displays Nothing - Oki MC873dn Maintenance Manual

Oki Data CONFIDENTIAL

2.5.5.(1) LCD Display Trouble

(1-1) LCD displays nothing

Check item
(1-1-1) Checking fuse
Fuse on Scanner board Check whether F2 or F6 has
(6SU) blown.
(1-1-2) Checking connections
Connection between low- Make sure the low-voltage
voltage power supply unit power supply unit is connected
and Scanner board (6SU) to the POWER_IN connector
on the Scanner board (6SU)
Cable assembly connecting
properly.
low-voltage power supply
Check whether the cable
unit to Scanner board (6SU)
connector is half-connected
or tilted, or whether wires are
broken.
Check whether there is any
fault in the cable assembly, e.g.,
missing wires.
Connection between Make sure the 22-pin FFC is
Scanner board (6SU) and connected to the 7 INCHIF
operation panel connector on the Scanner
board (6SU) properly.
Make sure the 22-pin FFC is
connected to the SUIF
connector
on Panel board (TP1)
properly.
Check whether the cable
connector is half-connected or
tilted.
FFC connecting Scanner Check for broken wires using a
board (6SU) to Panel board tester.
(TP1) Check visually whether the
sheath peels.
45850101TH Rev.1
Actions to be taken
Check work
at NG
Replace F2 or F6 or
Scanner board (6SU).
Connect the cable
properly.
Replace the cable with
a good cable.
Connect the cable
properly.
Replace the cable with
a good cable.
Check item
(1-1-2) Checking connections
Connection between Make sure the 50-pin FFC
Scanner board (6SU) and is connected to the CD2_CUIF
CU/PU board connector on the Scanner
board (6SU)
properly.
Make sure the 50-pin FFC
is connected to the CD2_CUIF
connector on the CU/PU board
(6CU) properly.
Check whether the cable
connector is half-connected or
tilted.
FFC connecting Scanner Check for broken wires using a
board (6SU) to CU/PU tester.
board (6CU) Check visually whether the
sheath peels.
(1-1-3) Checking power supplies
AC power supplied to the Check the supplied voltage
printer from the AC power source.
3.3VS and 5V power Check the 3.3VS power at 1 pin
supplied to Scanner board and 5V power at 3, 4 pin of the
(6SU) POWER_IN connector on the
Scanner board (6SU).
5V and 3.3VS power Check the power at pin of the
supplied to Panel board CN1 connector on the Panel
(TP1) board (TP1).
(1-1-4) Checking for short circuit of power supply
3.3VS, 5V and 24V power Check for a short circuit using
supplied to Scanner board the POWER connector on the
(6SU) Scanner board (6SU).
1pin: 3.3VS
3,4pin: 5V
7,8pin: 24V
2,5,6,9,10pin 0V
If there is a short circuit, locate
it.
Disconnect the cables from the
Scanner board (6SU) one by
one to
locate the short circuit.
2. TROUBLESHOOTING PROCEDURES
Actions to be taken
Check work
at NG
Connect the cable
properly.
Replace the cable with
a good cable
Supply AC power.
Replace the low
voltage power supply
or CU/PU board (6CU)
Replace the Scanner
board (6SU).
Replace the short-
circuited component.
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