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OKIPAGE 8c
Color LED Page Printer
Troubleshooting Manual
with Component Parts List
ODA/OEL/INT
1999. 2. 9 Rev.1
40985501TH Rev.1 1 / 157
CONTENTS
1. OUTLINE ............................................................................................................ 3
2. TOOLS................................................................................................................ 3
3. CIRCUIT DESCRIPTION.................................................................................... 4
3.1 CU (controller unit : PCR) ......................................................................... 4
3.1.1 Outline ...................................................................................................................... 4
3.1.2 CPU and Memory ..................................................................................................... 7
3.1.3 Reset Control ............................................................................................................ 9
3.1.4 EEPROM Control ................................................................................................... 10
3.1.5 Centronics Parallel Interface ................................................................................... 12
3.1.6 Operator Panel Control ........................................................................................... 13
3.2 PU (Printer Unit : PX4) ........................................................................... 14
3.2.1 Outline .................................................................................................................... 14
3.2.2 CPU, Memory and LSI ............................................................................................ 16
3.2.3 Reset Control .......................................................................................................... 18
3.2.4 EEPROM Control ................................................................................................... 19
3.2.5 LED Head Control .................................................................................................. 21
3.2.6 Motor Control .......................................................................................................... 24
3.2.7 Fuser Temperature Control ..................................................................................... 30
3.2.8 Fan Motor Control ................................................................................................... 33
3.2.9 Sensor Supervision ................................................................................................ 34
3.2.10 Cover Open ............................................................................................................ 35
3.2.11 Power Supply Interface ........................................................................................... 36
3.2.12 Option (2nd paper feeder) Interface ....................................................................... 37
3.2.13 Power Supply Board ............................................................................................... 38
3.3 PCR-PX4 I/F ........................................................................................... 42
3.3.1 Outline .................................................................................................................... 42
3.3.2 Video I/F ................................................................................................................. 43
3.3.3 Command Interface ................................................................................................ 45
4. TROUBLESHOOTING...................................................................................... 48
4.1 Troubleshooting Table ............................................................................ 48
4.2 Troubleshooting Flowchart ..................................................................... 60
5. CIRCUIT DIAGRAM ......................................................................................... 66
6. COMPONENT PARTS LIST ........................................................................... 104
40985501TH Rev.1 2/
1. OUTLINE
This manual has been written to provide guidance for troubleshooting of the OKIPAGE 8c Printer
(primarily for its printed circuit boards), on an assumption that the reader is knowledgeable of the
printer. Read the maintenance manual for this printer P/N 40029803TH if necessary.
Notes:
1. The power supply board containing a high voltage power supply is dangerous. From the
viewpoint of the safety standards, the local repairing of a defective board is not allowed. Also,
pay attention to the fact that a function can be rarely recovered by replacing a fuse when it is
burnt.
2. Replacement of CPU(NR4700) and LSIs (IMEM & IIF) on the PCR PCB is not recommended.
If these chips are founded to be defective, board replacement is suggested.
2. TOOLS
For troubleshooting the printer, the tools listed below may be needed in addition to general
maintenance tools.
Tool Remarks
Oscilloscope Frequency response 100 MHz or higher
Soldering iron A slender tip type, 15-20 Watt
Extension Cord Used for drawing PCR PCB out for PX4
PCB evaluation
40985501TH Rev.1 3/
3. CIRCUIT DESCRIPTION
3.1 CU (controller unit : PCR)
3.1.1 Outline
The PCR PCB controls the reception of data transferred through a host I/F and processes
command analysis, bit image development, raster buffer read. It also controls the operator panel.
The block diagram of the entire OKIPAGE 8c including PCR PCB and details of PCR PCB are
shown in Figure. 3-1 and 3-2.
(1) Reception control
The OKIPAGE 8c has one centronics parallel I/F.
The centronics parallel I/F port can specify the following item when set by the control panel:
PARALLEL SPEED: HIGH/MEDIUM
BI-DIRECTION : ENABLE/DISABLE
I-PRIME : OFF/ON
An interface task stores all data received from the host into a receive buffer first.
(2) Command analysis processing
The OKIPAGE 8c has the following emulation mode.
Color Laser Jet : Hewlett Packard
PostScript Level 3 : Adobe
An edit task fetches data from the receive buffer, analizes commands, and reconstructs the
data in such a way that print data are aligned from up to down and from right to left; then it writes
the resultant data into a page buffer with such control data as print position coordinate, font
type, etc. added.
(3) Font Processing
When one page editing is finished, a developing task makes an engine start and fetches data
from the page buffer synchronizing with a printing operation; then it developes the fetched data
to a bit map as referring to data from a character generator, and writes the resultant data into
the raster buffer (of band buffer structure).
(4) Raster buffer read.
As controlling the engine operation, an engine task sends data from the raster buffer to the
LED head.
40985501TH Rev.1 4/
AC-IN AC switch
Crimp-style terminal
Ejection sensor
LED head: Y M C K
PXL board
thermistor
6P
Heat roller
PXL
40985501TH Rev.1
6P'
Interlock switch
thermistor
Discharging lamp: Y M C K
SUMi card x 4 Backup roller
PD6 board JST3P
Y600 14P M600 14P C600 14P K600 14P Oil PAD MSW
Heater unit
YPOW 12P MPOW 12P CPOW 12P KPOW 12P
HEAD1 13P HEAD2 14P HEADPOW 12P HEAD3 15P
FF Pos MSW
ID sensor x 4
FF form Toner sensor x 4 FAN 1
Low-voltage power supply
sensor
FF Resist Y-IDU M-IDU C-IDU K-IDU Belt Heat
motor motor motor motor motor motor motor motor 3P
REG.POS
sensor
Paper supply sensor board
Figure 3-1 Block Diagram
PXM board FAN 2
40095001YU
UPDOWN
12P
TONER
YIDREG MCKID HETBELT HEAD3 HEAD2 HEAD1 HEADPOW
JODEN 8P 14P 8P 12P 8P 15P 14P 13P 12P
FF 12P RSENS 7P
FSENS 8P
PXF board THE.RM 6P Operator
PX4 board panel
PXFIF 30P PXFIF 30P POWER 30P
OPTION 7P HVOLT 16P COVOPN 2P PSIZE 6P CUIF 40P
PCO
board
PENDTNR 6P
PU 40P
PCR CM
Form size detector 6P
PXC board 72PX2 72PX2
Cover open PS SIMM D-RAM SIMM 64P 36P
High-voltage power supply MSW OKI HSP Paralle
2nd tray Form end Waste toner
(option) sensor sensor
5/
MPU Memory controller 16244 ROM, PS SIMM
64 A 22
SysAD SysAD
9 D 64
SysCmd SysCmd
5 Control 11 16245
Control Control
uPD94704
1
NMI NMI S1-001-F6 16244 D-RAM Max 80M
1 11
INTO INT A
64
D
NR4700 25 16245
Control
LMQ-100
16244 Engine
8
WDATA WDATA
1 4
CLK FSYNC ESYNC
1 4
RST Control Control
Interface controller 244
64 9
SysAD PU I/F Operator
9 4
SysCmd OP I/F panel
5 244
Control
ExtReg 1
ExtReq EE-PROM #1
INT1 1 1
INT EEPD DI
INT2 1
EEPCLK CLK DO
Reset 1
EEPCS0 CS PS -SIMM
ColdReset 1 ColdReset EE-PROM #2
VCCOK 1 VCCOK DI
ModeIn 1 ModeIn CLK DO
ModeClock 1 ModeClk 1
EEPCS1 CS
MasterClock
uPU66044
(Not installed)
GN-014-LMU
External Agent 74ACT1284 Bi-Centro
SysAD 8
PD
SysCmd 7
PCO
Control
74ALS244
INT PCI 4
REQ 1 BusReq
ACK 1 BusAck OKI HSP
AUX 2 AUX 16
D
18
A
CLK 12
C
RST 1
Reset
(Not installed) Host I/F
1
OSC CLK
1
Reset circuit RSTIN
2 10
DIP SW M
(TE6135 (6137), 16550, 53C80)
Figure 3-2 Block Diagram
40985501TH Rev.1 6/
3.1.2 CPU and Memory
(1) CPU (NR4700LMQ-100) (MIPS R4700)
CPU core : RISC CPU (MIPS R3000 compatible)
CPU clock : 100 MHz
Data bus clock : 50 MHz
Data bus width : Exterior 64 bits, Interior 64 bits
(2) ROM (HP Color LaserJet emulation)
ROM capacity : 8 Mbytes (16-Mbit mask or OTP ROM four pieces)
ROM type : 16 Mbits (1M x 16 bits)
Access time : 100 ns
(3) PostScript SIMM (Adobe PostScript emulation)
ROM capacity : 8 Mbytes [(16 Mbit ROM two pieces)x 2SIMMs]
ROM type : 16 Mbits (1M x 16 bits)
Access time : 100 ns
(4) Resident RAM
RAM capacity : 16 Mbytes (16 Mbit D-RAM eight pieces)
RAM type : 16 Mbits (1 M x 16 bits)
Access time : 60 ns
(5) Option RAM (SIMM: two slots)
RAM capacity : Max. 32 Mbytes (4 Mbytes, 8 Mbytes, 16 Mbytes, 32 Mbytes)
Access time : 60 ns, 70 ns, 80 ns
Note that only the product for ODA has been mounted with 16 Mbytes (8 Mbytes x 2) SIMM
as a resident.
The block diagram of CPU and memory circuits is shown in Figure 3-3.
40985501TH Rev.1 7/
(NR4700 LMQ-100) (Memory Control LSI)
CPU IMEM
16Mbit DRAM x 4
Control signals 11 11
DRAM01~04
(RAS0, CAS7~0)
AD [63 : 0] 16244
64 64
16Mbit DRAM x 4
Resident RAM
(16M Bytes)
DRAM11~14
CMD [7 : 0] (RAS2, CAS7~0)
16245 x 4
SIMM0 H, L
(RAS4, 5, CAS7~0) Option SIMM
16244 (Resident SIMM:
16MbitMask ROM x 4
Only ODA)
CAS01~04
(CS0) Mask ROM
16244
(8M Bytes)
4Mbit Flash ROM x 4
16245 x 4
IFL1~4 Flash ROM
(CS3) (2M Bytes)
16244
16MbitMask ROM x 2 x 2
PSIMMH, L PS SIMM
(I/F Control LSI) (CS2) (8M Bytes)
IIF
Figure 3-3 Block Diagram of CPU & Memory
40985501TH Rev.1 8/
3.1.3 Reset Control
When power is turned on, a RESET-N signal is generated by the reset control IC (7705) which
checks +5V power supply.
OKI HSP
IMEM
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