45530603TH Rev.2
4-37
Oki Data CONFIDENTIAL
4. TROUBLESHOOTING PROCEDURE
4.5.2 (1) LCD display error
Memo For connector names, see beside the connectors on each PCB where
connector names are silkscreen printed.
(1-1) LCD does not display anything.
Check item Check work
Actions to be taken
at NG
(1-1-1) Check the fuse.
Printer control PCB
(PU/CU PCB) fuse
Check if F22 or F23 has blown out. Replace the PU/
CU PCB.
(1-1-2) Check the system connection
Connection
between the low
voltage power
supply unit and the
PU/CU PCB
Check if the cable from the low voltage power
supply to the POWER connector of the PU/
CU PCB is normally connected.
Check if the connector is connected only in
the half-way, and check if the connector is
inserted in slanted angle.
Re-connect the
cable normally.
Cable assembly
connecting the
low voltage power
supply unit and the
PU/CU PCB
Check if the cable is half-open circuit.
Check if the sheath of the cable has peeled
off.
Check if the cable assembly is defective such
as internal wires are disconnected.
Replace with a
normal cable.
Connection
between the PU/
CU PCB and the
control panel PCB
Check if the cable is normally connected to
the FPD connector of the PU/CU PCB.
Check if the cable is normally connected to
the MAIN connector of the control panel PCB.
Check if the connector is connected in the
halfway only, and check if the connector is
inserted in a slanted angle.
Re-connect the
cable normally.
FFC connecting the
PU/CU PCB and
the control panel
PCB
Check if the cable has open circuit with VOM.
Visually check the sheath of the cable for
peeling.
Replace with a
normal cable.
Connection
between the control
panel PCB and the
LCD
Check if the FCP is normally connected to the
LCD connector of the control panel PCB.
Replace the
control panel
unit.
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 PCB
Check for 5V power supply at pin-8, -10 and
-21 of the POWER connector of the PU/CU
PCB.
Replace the low
voltage power
supply unit.
5V power that is
supplied to the PU/
CU PCB
Check for 5V power supply at pin-19 of the
POWER connector of the PU/CU PCB.
Replace the low
voltage power
supply unit.
Power that is
supplied to the
control panel PCB
Check for 3.3V power supply at pin-21 of the
MAIN connector of the control panel PCB.
Also check for 5V at pin-25 of the MAIN
connector.
Replace the PU/
CU PCB.
(1-1-4) Check that power supply circuit has no short-circuit.
5V power and 24V
power that are
supplied to the PU/
CU PCB.
Check the POWER connector of the PU/CU
PCB for a short-circuit. The following voltage
must appear respectively.
24V: pin-13, -14, and -16
5V: pin-8, -10 and -21
5VS: pin-19
0V: pin-9, -11, -12, -15, -18, -20, and -22
If any voltage does not appear and short-
circuit is detected, locate the source of the
short-circuit by disconnecting the cables from
the PU/CU PCB 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
Normal running of
the CU firmware
Check LED 1, 2 and 3 beside the CPU.
LED 1: On
LED 2 and 3: Off
Replace the PU/
CU PCB.
To Next Page
Loading...
