Oki B721 Maintenance Manual

Oki Data CONFIDENTIAL
45487001TH Rev.1
6-32 /
6. Troubleshooting procedure
(1-2) Error message related to the control panel
Check item Check work
Actions to be taken
at NG
(1-2-1) Error message
Error message Check the error contents by referring to the
Error Message List.
Follow the
instruction.
(1-3) “RAM checking” or “Initializing” remains displayed.
Check item Check work
Actions to be
taken at NG
(1-3-1) Control panel displays freezes.
Control panel
display
The control panel keeps displaying “RAM
checking” or “Initializing.”
Replace the PU/
CU board.
If the problem
remains
unsolved after
an optional RAM
or SD memory
card is removed,
replace the PU/
CU board.
6.5.2.(2) Abnormal operations of the printer after the power is turned on
(2-1) Any operation does not start at all.
Check item Check work
Actions to be taken
at NG
(2-1-1) 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 and 24V
power that are
supplied to the PU/
CU board
Check the power supply voltages at the
POWER connector
of the PU/CU board.
pin-11, -13, -14, -15, -16: 24V
pin-1, -2, -3, -4: 5V
pin-5, -6, -7, -8, -9: 0VL
pin-17, -18, -19, -20, -21: 0VP
pin-10: 5Vs
Replace the low
voltage power
supply unit.
(2-1-2) Power switch LED check
Power switch LED Check if the LED light stays off. Replace one of
the following: low
voltage power
supply unit, PU/
CU board, power
SW board, the
cable between
the low voltage
power supply
unit and the PU/
CU board, the
cable between
PU/CU board or
the power SW
board.
When blinking:
Replace one of
the following: low
voltage power
supply unit, PU/
CU board, power
SW board, or the
cable between
the low voltage
power supply
unit and the PU/
CU board board.

Oki B721 Specifications

General

Print Technology	LED
Resolution	1200 x 1200 dpi
Processor	533 MHz
Memory	256 MB
Connectivity	USB, Ethernet
Duplex Printing	Standard