Brother DP-550CJ, LW-840ic Service manual

R

WORD PROCESSOR

SERVICE MANUAL

MODEL:DP-525CJ/DP-530CJ/DP-540CJ/DP-550CJ

LW-800ic/LW-810ic/LW-810icBL/LW-840ic

REVISED EDITION

SERVICE MANUAL

CONTENTS

PART I THEORY OF OPERATION

CHAPTER 1 MECHANICAL THEORY....................................................................... 1-1

1. Ink Jet Printer........................................................................................................... 1-1

1.1. Ink Jet Printer System Configuration .......................................................................... 1-2

1.2. Ink Jet Operation........................................................................................................1-4

1.2.1. Paper Feed Mechanism ................................................................................ 1-4

1.2.2. Carriage Assembly ....................................................................................... 1-7

1.2.3. Carriage Motion Control.............................................................................. 1-10

1.2.4. Maintenance Station Operation................................................................... 1-11

1.2.4.1. Spitting ................................................................................................. 1-12

1.2.4.2. Wiping.................................................................................................. 1-13

1.2.4.3. Capping................................................................................................ 1-14

1.2.4.4. Purging................................................................................................. 1-14

1.2.5. Sensors...................................................................................................... 1-15

1.2.5.1. Carriage Home Position Sensor............................................................ 1-15

1.2.5.2. PE Sensor ............................................................................................ 1-16

1.3. INK CHG (Ink Change) Functions.............................................................................1-17

1.3.1. Ink Cartridge Installation/Replacement ....................................................... 1-17

1.3.2. Automatic Print head Cleaning (Purging).................................................... 1-17

2. Keyboard ................................................................................................................ 1-18

CHAPTER 2 ELECTRICAL THEORY........................................................................ 2-1

1. System Configuration...............................................................................................2-1

1.1. Main PCB (Printed Circuit Board)............................................................................... 2-1

1.2. Switch PCB (Printed Circuit Board)............................................................................. 2-1

1.3. Keyboard FPC (Flexible Printed Circuit)..................................................................... 2-1

1.4. FDD (Floppy Disk Drive) Module................................................................................ 2-1

1.5. CRT Display............................................................................................................... 2-1

2. Ink Jet Printer Configuration.....................................................................................2-3

2.1. Ink Cartridge............................................................................................................... 2-3

2.2. Carriage Motor ........................................................................................................... 2-3

2.3. Line Feed Motor......................................................................................................... 2-3

2.4. Carriage Home Position Sensor.................................................................................. 2-3

2.5. PE (Paper End) Sensor ..............................................................................................2-3

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3. Power Supply Circuit................................................................................................ 2-4

3.1. Configuration.............................................................................................................. 2-4

3.2. +24V Generator.......................................................................................................... 2-5

3.3. +5V Generator............................................................................................................ 2-5

4. Reset Circuit.............................................................................................................2-6

4.1. Configuration.............................................................................................................. 2-6

5. CBIC and Peripherals............................................................................................... 2-7

5.1. CBIC #9 ..................................................................................................................... 2-7

5.2. Main ROM (#12, #13)................................................................................................. 2-7

5.3. Main RAM (#10, #11) ................................................................................................. 2-7

5.4. Video RAM (#7) .......................................................................................................... 2-7

5.5. Printer Driver Circuits (#2, #3, Q1 to Q4, and Q14 to Q17)......................................... 2-7

5.6. FDC (Floppy Disk Controller)...................................................................................... 2-7

5.7. Clock Circuit............................................................................................................... 2-8

5.8. Buzzer Drive Circuit ................................................................................................... 2-8

5.9. Country Specification Change-over ............................................................................2-9

5.10. RS-232C I/F Circuit.................................................................................................. 2-10

6. Printer Control........................................................................................................ 2-11

6.1. Ink Jet Head Control ................................................................................................. 2-11

6.2. Carriage Motor Control............................................................................................. 2-12

6.3. Line Feed Motor Control........................................................................................... 2-13

6.4. Carriage Home Position Sensor................................................................................ 2-14

6.5. PE Sensor................................................................................................................ 2-14

7. Switch PCB ............................................................................................................2-15

7.1. Configuration............................................................................................................ 2-15

8. Keyboard System................................................................................................... 2-16

8.1. FPC Operation ......................................................................................................... 2-16

8.2. Keyboard Scan......................................................................................................... 2-17

8.3. Keyboard Control Circuit........................................................................................... 2-18

9. CRT Control ........................................................................................................... 2-20

9.1. Configuration............................................................................................................ 2-20

9.2. SRAM and Display Screen Relationship................................................................... 2-21

9.2.1. SRAM (#7) Access ..................................................................................... 2-22

9.2.2. CRT Display Timing Chart.......................................................................... 2-23

10. FDD (Floppy Disk Drive) Control ............................................................................2-24

10.1. FDD Configuration.................................................................................................... 2-24

10.2. FDD Operation......................................................................................................... 2-25

10.2.1. Basic Operation.......................................................................................... 2-25

10.2.2. Interface between CBIC (#8) and FDC (#5)................................................. 2-25

10.3. FDD Module............................................................................................................. 2-26

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10.3.1. Read/Write Circuit...................................................................................... 2-26

10.3.2. Motor Drive Circuit...................................................................................... 2-26

10.3.3. Sensor Circuits........................................................................................... 2-26

PART II REPAIR

CHAPTER 3 TROUBLESHOOTING..........................................................................3-1

1. Introduction .............................................................................................................. 3-1

2. Precautions..............................................................................................................3-1

2.1. Personal Safety.......................................................................................................... 3-1

2.2. Handling ESD-Sensitive Parts.................................................................................... 3-1

3. Checks Before Repair.............................................................................................. 3-2

4. Checks After Repair................................................................................................. 3-3

5. Troubleshooting Flow Charts....................................................................................3-4

6. Failure Analysis........................................................................................................3-6

7. SELF-TESTS..........................................................................................................3-13

7.1. SERIAL NUMBER Input Display............................................................................... 3-13

7.2. Self Print Mode......................................................................................................... 3-14

7.3. Self-Test Mode......................................................................................................... 3-17

7.3.1. Display (CRT) Test..................................................................................... 3-19

7.3.1.1. Cross Hatch Pattern Test...................................................................... 3-20

7.3.1.2. Full Dot Screen Test............................................................................. 3-21

7.3.1.3. Blank Screen Test ................................................................................ 3-22

7.3.1.4. H Pattern Test ...................................................................................... 3-23

7.3.1.5. mw Pattern Test.................................................................................... 3-24

7.3.1.6. Dot Pattern Test.................................................................................... 3-25

7.3.2. Print Checks............................................................................................... 3-26

7.3.2.1. Print Test Pattern 1............................................................................... 3-26

7.3.2.2. Print Test Pattern 2............................................................................... 3-29

7.3.2.3. Dot Patterns.......................................................................................... 3-31

7.3.3. Keyboard Tests........................................................................................... 3-33

7.3.4. FDD Tests.................................................................................................. 3-36

7.3.4.1. FDD Test.............................................................................................. 3-36

7.3.4.2. Special FDD Test.................................................................................. 3-37

7.3.4.3. FDD SW Test ....................................................................................... 3-41

7.3.4.4. FDD Write Error Rate Check ................................................................ 3-42

7.3.4.5. FDD Read Error Rate Check................................................................. 3-44

7.3.5. PE (Paper-End) Sensor Test....................................................................... 3-46

7.3.6. CR (Carriage Reset) Test ........................................................................... 3-47

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7.3.7. DISK TYPE ................................................................................................ 3-48

7.3.8. RS-232C Test ("Echo Back") ...................................................................... 3-49

CHAPTER 4 COMPONENT DISASSEMBLY............................................................. 4-1

1. Covers...................................................................................................................... 4-1

1.1. Upper Cover ............................................................................................................... 4-2

1.1.1. Removing the Upper Cover.......................................................................... 4-2

1.1.2. Removing the Front Cover ........................................................................... 4-6

1.1.3. Installing the Upper Cover ............................................................................4-7

2. Keyboard Assembly ................................................................................................. 4-8

2.1. Removing the Keyboard............................................................................................. 4-8

2.2. Installing the Keyboard............................................................................................... 4-9

3. Ink Jet Printer Assembly.........................................................................................4-10

3.1. Removing the Printer Assembly ............................................................................... 4-11

3.2. Installing the Printer Assembly.................................................................................. 4-11

3.3. Disassembling the Printer Assembly ......................................................................... 4-12

3.3.1. Removing the CA Unit................................................................................ 4-13

3.3.2. Installing the CA Unit.................................................................................. 4-13

3.3.3. Disassembling the PF Unit.......................................................................... 4-14

3.3.3.1. Removing the Form.............................................................................. 4-15

3.3.3.2. Removing the Release Lever and Release Shaft.................................. 4-16

3.3.3.3. Removing the ACF Shaft Assembly...................................................... 4-17

3.3.3.4. Removing the Pressure Rollers and Roller Holders............................... 4-18

3.3.3.5. Removing the Holder Plate................................................................... 4-19

3.3.3.6. Removing the Hopper Assembly........................................................... 4-20

3.3.3.7. Disassembling the Paper Feed Assembly ............................................. 4-22

3.3.3.8. Removing the Eject Roller Assembly and the PF Roller Assembly........ 4-23

3.3.3.9. Removing the Motor Frame Assembly.................................................. 4-24

3.3.3.10. Removing the PF Stopper..................................................................... 4-25

3.3.3.11. Removing the PE Sensor...................................................................... 4-26

3.3.4. Disassembling the CA Unit ......................................................................... 4-27

3.3.4.1. Removing the Carriage......................................................................... 4-28

3.3.4.2. Removing the Carriage Drive................................................................ 4-30

3.3.4.3. Removing the Star Wheel Holder Assembly ......................................... 4-31

3.3.4.4. Removing the MS Holder Assembly...................................................... 4-32

3.3.4.5. Removing the Leaf Switch (Home Position Sensor).............................. 4-33

3.3.4.6. Removing and Mounting the KB Switch Assy........................................ 4-34

3.4. Adjusting the CA Unit ............................................................................................... 4-35

3.4.1. Adjusting the Carriage Home Position......................................................... 4-35

3.4.2. Adjusting Belt Tension................................................................................ 4-36

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4. Removing the FDD Assembly ................................................................................ 4-39

5. Switch PCB ............................................................................................................4-40

5.1. Removing the Switch PCB ....................................................................................... 4-41

5.2. Installing the Switch PCB.......................................................................................... 4-41

6. Removing the Main PCB........................................................................................ 4-42

7. Removing the Shield Plate (ESD) .......................................................................... 4-43

CHAPTER 5 MONITOR REPAIR AND ADJUSTMENT (MODEL CT-1450).............. 5-1

1. Safety Precautions...................................................................................................5-1

2. Theory of Operation.................................................................................................5-3

2.1. Video Process ............................................................................................................5-3

2.2. Video Amplifier ........................................................................................................... 5-3

2.3. Vertical Circuitry......................................................................................................... 5-4

2.4. Horizontal Sync and Drive.......................................................................................... 5-4

2.5. Horizontal Output Transistor....................................................................................... 5-5

2.6. High Voltage and Focus ............................................................................................. 5-5

3. Adjustment and Servicing......................................................................................... 5-6

3.1. Test Pattern................................................................................................................ 5-6

3.2. Measurement Conditions............................................................................................ 5-7

3.2.1. Display Dimension Measurement.................................................................. 5-7

3.2.2. Raster Centering & Tilt Adjustment (see Fig. 5.3) .........................................5-7

3.3. Adjustments ............................................................................................................... 5-8

3.3.1. B+ Voltage Adjustments: None required. ..................................................... 5-8

3.3.2. Horizontal Adjustments................................................................................. 5-8

3.3.3. Vertical Adjustments (see Fig. 5.5) ...............................................................5-9

3.3.4. Brightness & Contrast................................................................................... 5-9

3.3.5. Focus Adjustment......................................................................................... 5-9

3.3.6. Raster Geometry Adjustments.................................................................... 5-10

3.3.6.1. Pin Cushion/Barrel Correction (top, bottom and sides) Adjustment........ 5-10

3.3.6.2. Trapezoidal Correction (corners) Adjustment ........................................ 5-12

4. Troubleshooting ..................................................................................................... 5-13

5. Control Parts Location............................................................................................5-14

6. Monitor Block Diagram...........................................................................................5-15

CHAPTER 6 MAINTENANCE .................................................................................... 6-1

1. Lubrication................................................................................................................ 6-1

1.1. Lubricants................................................................................................................... 6-1

1.2. Precautions ................................................................................................................6-1

1.3. Lubrication Points....................................................................................................... 6-1

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2. Replacing the Ink Cartridge...................................................................................... 6-5

3. Cleaning the Print Head........................................................................................... 6-9

3.1. Cleaning the Print Head Automatically........................................................................ 6-9

3.2. Cleaning the Ink Jet Nozzles and Contacts................................................................. 6-9

3.3. Cleaning the Bracket Contacts (Carriage)................................................................. 6-10

APPENDIX A SPECIFICATIONS...........................................................................APP-1

1. Electrical System.................................................................................................APP-1

2. Printing................................................................................................................APP-2

3. Keyboard .............................................................................................................APP-4

4. Monitor (CT-1450)...............................................................................................APP-4

5. Environmental Tolerance ....................................................................................APP-5

6. Dimensions & Weight..........................................................................................APP-6

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FIGURES

Figure Title Page

Fig. 1.1 Ink Jet Printer Assembly....................................................................................... 1-1

Fig. 1.2 General View of Printing Mechanism .................................................................... 1-3

Fig. 1.3A Paper Feed Mechanism ................................................................ ........................ 1-4

Fig. 1.3B Paper Feed Mechanism ................................................................ ........................ 1-5

Fig. 1.4 Paper Eject System.............................................................................................. 1-5

Fig. 1.5 Paper Setting System........................................................................................... 1-6

Fig. 1.6 Printer Flat Cable to Main PCB............................................................................. 1-7

Fig. 1.7 Printer Flat Cable to Cartridge Alignment.............................................................. 1-8

Fig. 1.8 Ink Jet Cartridge to Flat Cable Alignment.............................................................. 1-9

Fig. 1.9 Carriage Motion Control ................................................................ ...................... 1-10

Fig. 1.10 Print Maintenance Operation - Spitting................................................................ 1-12

Fig. 1.11 Print Maintenance Operation - Wiping................................................................. 1-13

Fig. 1.12 Print Maintenance Operation - Capping .............................................................. 1-14

Fig. 1.13 Carriage Home Position Sensor ................................ .......................................... 1-15

Fig. 1.14 PE Sensor Mechanism....................................................................................... 1-16

Fig. 1.15 Keyboard Assembly............................................................................................ 1-18

Fig. 1.16 Key Top/Key Stem Assembly ............................................................................. 1-19

Fig. 1.17 LCD Unit Installation in the Upper Cover ................................ ............................. 1-21

Fig. 1.18 LCD of DP-525CJ/LW-800ic............................................................................... 1-22

Fig. 1.19 LCD of DP-530CJ/LW-810ic and LW-810icBL .................................................... 1-23

Fig. 1.20 LCD of DP-540CJ, DP-550CJ/LW-840ic............................................................. 1-24

Fig. 2.1 Major Electronic Component Parts........................................................................ 2-2

Fig. 2.2 Power Supply Circuit ............................................................................................ 2-4

Fig. 2.3 Timing Chart of +24V Generation Circuit............................................................... 2-5

Fig. 2.4 Timing Chart of +5V Generation Circuit ................................................................ 2-5

Fig. 2.5 Reset Circuit......................................................................................................... 2-6

Fig. 2.6 Buzzer Drive Circuit.............................................................................................. 2-8

Fig. 2.7 Country & Model Specification Change-over Circuit.............................................. 2-9

Fig. 2.8 RS-232C I/F Circuit ............................................................................................ 2-10

Fig. 2.9 Ink Jet Head Drive Circuit................................................................................... 2-11

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Figure Title Page

Fig. 2.10 Carriage Motor Drive Circuit................................................................................ 2-12

Fig. 2.11 Line Feed Motor Drive Circuit ............................................................................. 2-13

Fig. 2.12 Carriage Home Position Sensor Circuit............................................................... 2-14

Fig. 2.13 PE Sensor Detection Circuit ............................................................................... 2-14

Fig. 2.14 External View of the Switch PCB........................................................................ 2-15

Fig. 2.15 Switch PCB Circuit ............................................................................................. 2-15

Fig. 2.16 Key/FPC Operation ............................................................................................ 2-16

Fig. 2.17 Electrode Wiring................................................................................................. 2-17

Fig. 2.18 Keyboard Control Circuit ................................................................ ..................... 2-18

Fig. 2.19 Keyboard Matrix ................................................................................................. 2-19

Fig. 2.20 Keyboard Symbols (Corresponding to Keyboard Matrix in Fig. 2.19)................... 2-19

Fig. 2.21 LCD Display Operation Block Diagram................................................................ 2-20

Fig. 2.22 Example of Control Signal Timing Chart.............................................................. 2-21

Fig. 2.23 LCD Drive Voltage Generation Circuit (Minus Voltage VEE)................................ 2-22

Fig. 2.24 LCD Drive Voltage Generation Circuit (Plus Voltage VEE).................................. 2-22

Fig. 2.25 CFL Backlight Circuit.......................................................................................... 2-23

Fig. 2.26 FDD Block Diagram............................................................................................ 2-25

Fig. 3.1 Troubleshooting Flowchart.................................................................................... 3-4

Fig. 3.2 Troubleshooting Flowchart (continued) ................................................................. 3-5

Fig. 3.3 Serial Number Entry Display............................................................................... 3-14

Fig. 3.4 Self-Print Pattern................................................................................................ 3-15

Fig. 3.5 Results of Self-Print Test.................................................................................... 3-17

Fig. 3.6 Self-Test Menu................................................................................................... 3-18

Fig. 3.7 LCD Test Menu.................................................................................................. 3-20

Fig. 3.8 CHECK Test Display (magnified)........................................................................ 3-21

Fig. 3.9 CROSS Test Display (magnified)........................................................................ 3-22

Fig. 3.10 BLACK Test Display........................................................................................... 3-23

Fig. 3.11 DISP Q Test Display (magnified)........................................................................ 3-24

Fig. 3.12 Slant Line Test Display (magnified)..................................................................... 3-25

Fig. 3.13 Printer Check #1 (in progress) Display................................................................ 3-26

Fig. 3.14 Diagram of Print Test Pattern 1 .......................................................................... 3-27

Fig. 3.15 Sample Print Test Pattern 1................................................................................ 3-28

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Figure Title Page

Fig. 3.16 Printer Check #2 (in progress) Display................................................................ 3-29

Fig. 3.17 Sample Test Pattern 2........................................................................................ 3-30

Fig. 3.18 Dot Patterns for Print Test #2 (Patterns 1 to 4)................................................... 3-31

Fig. 3.19 Dot Patterns for Print Test #2 (Patterns 5 and 6) ................................................ 3-32

Fig. 3.20 Keyboard Test #1 Display ................................................................ ................... 3-33

Fig. 3.21 Keyboard Test Key Locations............................................................................. 3-33

Fig. 3.22 FDD Test (in progress) Display ................................ ........................................... 3-36

Fig. 3.23 Special FDD Test Display 1................................................................................ 3-37

Fig. 3.24 Special FDD Test Display 2................................................................................ 3-38

Fig. 3.25 Special FDD Test (in progress) Display .............................................................. 3-38

Fig. 3.26 Special FDD Test Display 1................................................................................ 3-41

Fig. 3.27 FDD Write Error Rate Check Display.................................................................. 3-42

Fig. 3.28 FDD Read Error Rate Check Display.................................................................. 3-44

Fig. 3.29 PE Sensor Test Start Display 1 .......................................................................... 3-46

Fig. 3.30 PE Sensor Test Start Display 2 .......................................................................... 3-46

Fig. 3.31 CR Test Start Display 1...................................................................................... 3-47

Fig. 3.32 Self-Test Menu (DISK TYPE Setting) ................................................................. 3-48

Fig. 3.33 RS232C Echo-Back Test Start Display............................................................... 3-49

Fig. 4.1 Cover Assemblies................................................................................................. 4-1

Fig. 4.2 Removing the Sub Paper Support and Paper Support .......................................... 4-3

Fig. 4.3 Removing the Top Cover...................................................................................... 4-4

Fig. 4.4 Removing the Upper Cover................................................................................... 4-5

Fig. 4.5 Removing the Core............................................................................................... 4-8

Fig. 4.6 Removing the LCD Unit........................................................................................ 4-9

Fig. 4.7 Removing the LCD Lower Cover......................................................................... 4-10

Fig. 4.8 Removing the LCD PCB (1)................................................................................ 4-12

Fig. 4.9 Removing the LCD PCB (2)................................................................................ 4-13

Fig. 4.10 Removing the LCD PCB (3)................................................................................ 4-14

Fig. 4.11 Removing the LCD PCB (4)................................................................................ 4-15

Fig. 4.12 Removing the LCD PCB (5)................................................................................ 4-16

Fig. 4.13 Removing LCD Latch and LCD Plate.................................................................. 4-17

Fig. 4.14 Installing LCD Latch............................................................................................ 4-19

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SERVICE MANUAL

Figure Title Page

Fig. 4.15 Fitting LCD Volume Guide to LCD Volume Knob................................................. 4-21

Fig. 4.16 Installing the LCD Lower Cover........................................................................... 4-22

Fig. 4.17 Fitting the Core ................................................................ .................................. 4-23

Fig. 4.18 Installing the Hinge Assy..................................................................................... 4-24

Fig. 4.19 Removing the Keyboard Assembly ..................................................................... 4-25

Fig. 4.20 Installing the Keyboard ....................................................................................... 4-26

Fig. 4.21 Removing the Carrying Handle........................................................................... 4-27

Fig. 4.22 Ink Jet Printer Assembly..................................................................................... 4-28

Fig. 4.23 Disassembling the Printer Assembly................................................................... 4-30

Fig. 4.24 Construction of the PF Unit................................................................................. 4-32

Fig. 4.25 Removing the Form............................................................................................ 4-33

Fig. 4.26 Removing the Release Lever and Release Shaft from the PF Base Assembly.... 4-34

Fig. 4.27 Removing the ACF Shaft Assembly.................................................................... 4-35

Fig. 4.28 Removing the Pressure Rollers and Roller Holders............................................. 4-36

Fig. 4.29 Removing the Holder Plate................................................................................. 4-37

Fig. 4.30 Removing the Hopper Assembly ................................ ......................................... 4-39

Fig. 4.31 Disassembling the Paper Feed Assembly........................................................... 4-40

Fig. 4.32 Removing the Eject Roller Assembly and the PF Roller Assembly...................... 4-41

Fig. 4.33 Removing the Motor Frame Assembly................................................................ 4-42

Fig. 4.34 Removing the PF Stopper................................................................................... 4-43

Fig. 4.35 Removing the PE Sensor.................................................................................... 4-44

Fig. 4.36 Construction of the CA Unit ................................................................................ 4-45

Fig. 4.37 Printer Mechanism.............................................................................................. 4-46

Fig. 4.38 Removing the Carriage....................................................................................... 4-47

Fig. 4.39 Removing the Carriage Drive.............................................................................. 4-48

Fig. 4.40 Removing the Star Wheel Holder Assembly........................................................ 4-49

Fig. 4.41 Removing the MS Holder Assembly.................................................................... 4-50

Fig. 4.42 Removing the Leaf Switch (Home Position Sensor) ............................................ 4-51

Fig. 4.43 Removing and Mounting the KB Switch Assy...................................................... 4-52

Fig. 4.44 Adjusting the Belt Tension.................................................................................. 4-55

Fig. 4.45 Measuring Friction during Carriage Movement.................................................... 4-56

Fig. 4.46 Removing the FDD Assembly............................................................................. 4-57

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Figure Title Page

Fig. 4.47 Switch PCB........................................................................................................ 4-58

Fig. 4.48 Switch PCB........................................................................................................ 4-59

Fig. 4.49 Removing the Main PCB..................................................................................... 4-60

Fig. 4.50 Removing the Shield Plate (ESD)....................................................................... 4-61

Fig. 5.1 Carriage Assembly Lubrication Points................................................................... 5-2

Fig. 5.2 Paper Feed Assembly Lubrication Points ................................ .............................. 5-3

Fig. 5.3 Eject Roller Assembly and PF Roller Assembly Lubrication Points........................ 5-4

Fig. 5.4 Open the Paper Support and Top Cover and

Tilting the LCD to the Uprige Position ................................................................... 5-6

Fig. 5.5 Removing the Ink Jet Cartridge............................................................................. 5-7

Fig. 5.6 Removing the Protection Tape.............................................................................. 5-7

Fig. 5.7 Placing the Cartridge in the Carriage .................................................................... 5-8

Fig. 5.8 Fitting the Cartridge in the Carriage ...................................................................... 5-8

Fig. 5.9 Cleaning the Bracket Contacts............................................................................ 5-11

TABLES

Table 1.1 Summary of Maintenance Operations................................................................. 1-11

Table 2.1 Clock Circuit ......................................................................................................... 2-8

Table 2.2 Table of LCD Modules........................................................................................ 2-21

Table 2.3 FDC(#5) and FDD Module Links (Interface Signals)............................................ 2-24

Table 3.1 Failure Analysis .................................................................................................... 3-6

Table 3.2 FDD Special Test Error Stage Codes ................................................................. 3-39

Table 3.3 FDD Special Test Error Codes............................................................................ 3-40

Table 5.1 Recommended Lubricants .................................................................................... 5-1

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PART I THEORY OF OPERATION

CHAPTER 1 MECHANICAL THEORY

1. Ink Jet Printer

THEORY

Mechanical

Fig. 1.1 Ink Jet Printer Assembly

1-1

THEORY

Mechanical

1.1. Ink Jet Printer System Configuration

The ink jet printer contains the following components:

Carriage assembly

•

Carriage motion control system

•

Paper feed mechanism

•

Maintenance station

•

Sensors

•

The outline of these components are described below.

1. Carriage Assembly
The carriage assembly consists of the carriage and ink cartridge (the cartridge

contains the ink jet nozzles). The carriage consists of the head locker and locker
spring, the rubber pad, and the flat cable.

SERVICE MANUAL

2. Carriage Motion Control System
The carriage motion control system consists of the carriage motor, motor pulley,

timing belt, idle pulley, and the idle pulley holder and holder spring.

3. Paper Feed Mechanism
The paper feed mechanism consists of the paper feed system, paper eject system,

and the paper setting system.

4. Maintenance Station
The maintenance station consists of the MS holder, the MS carriage assembly

(carriage, rubber cap, plunger, compression spring, and extension spring), the wiper,
and the felt form ink absorbers (in spitting trough and under carriage assembly ).

5. Sensors
There are two sensors in the printer assembly: the carriage home position sensor

(attached to the top right end of the CA frame) and the paper end sensor (attached to
the bottom of the PF base at the right rear).

1-2

SERVICE MANUAL

THEORY

Mechanical

Fig. 1.2 General View of Printing Mechanism

1-3

THEORY

Mechanical

1.2. Ink Jet Operation

1.2.1. Paper Feed Mechanism

The paper feed mechanism consist of the paper feed system, paper eject system, and
the paper setting system.

(1) The paper feed system consists of the ACF shaft gear, separate roller, ACF shaft

locker, locker spring, idle gears 1, 2, 3, and 4, PF roller gear, changer lever 1 and 2,
spring, and the line feed motor.
Paper feed system ACF(Auto cut-sheet feeder)
When the paper feed motor is driven in the opposite direction (reverse rotation) of the
paper feeding, the change lever 1 moves to engage the ACF shaft gear via the idle
gear. The separate roller rotates in the paper separation direction (normal rotation)
and separates a sheet of paper. The separate roller rotates with paper feeding
operation and returns to the initial position. Separated paper is fed to contact PF
roller and the pressure roller by the separate roller where the top of the paper is
registered.

SERVICE MANUAL

Fig. 1.3A Paper Feed Mechanism

1-4

SERVICE MANUAL

THEORY

Mechanical

Fig. 1.3B Paper Feed Mechanism

(2) The paper eject system consists of the line feed motor, collar, idle gears 1, 5, and 6,

PF roller gear, eject roller gear, pressure roller, roller holder, holder plate, pressure
roller spring, star wheel holder, and the star wheel.
After paper is registered, the paper feed motor is driven in the paper feeding direction
(normal rotation) and paper is fed by the PF roller and the pressure roller. After
printing paper is ejected by the eject roller and star wheel.

Fig. 1.4 Paper Eject System

1-5

THEORY

Mechanical

(3) The paper setting system consists of the hopper, hopper spring, separate pad, collar,

SERVICE MANUAL

paper guide, ACF change lever, change spring, and the ACF change shaft.
When inserting a thick paper, the ACF change lever should place at the front
position.

24lb Thick Paper

Envelope
Label
Transparency etc.

Fig. 1.5 Paper Setting System

1-6

SERVICE MANUAL

1.2.2. Carriage Assembly

The carriage assembly consists of the carriage and ink cartridge (the cartridge contains
the ink jet nozzles). The carriage consists of the head locker and locker spring, the
rubber pad, and the flat cable. The flat cable connects to the main PCB. See Fig. 1.6.

The printer flat cable must be firmly in contact with the ink jet cartridge for printing to be
enabled. The flat cable is located in the carriage by four alignment pins; proper
alignment of the cartridge to the cable is established in three datums (reference
planes/points): X, Y, and Z. When the cartridge is installed in the carriage, the flat cable
contacts are compressed against the cartridge contacts by the rubber pad. See Figs.

1.7 and 1.8.

THEORY

Mechanical

Fig. 1.6 Printer Flat Cable to Main PCB

1-7

THEORY

Mechanical

SERVICE MANUAL

Fig. 1.7 Printer Flat Cable to Cartridge Alignment

1-8

SERVICE MANUAL

THEORY

Mechanical

Fig. 1.8 Ink Jet Cartridge to Flat Cable Alignment

1-9

THEORY

Mechanical

1.2.3. Carriage Motion Control

All operations related to carriage movement are driven by the CA motor. The CA motor
assembly consists of a motor, a timing belt, an idle pulley, and an idle pulley holder and
pulley holder spring: the motor and the idle pulley holder are mounted to the CA frame;
the belt runs between the motor and the pulley. The pulley holder spring between the
idle pulley holder and the CA frame sets belt tension. See Fig. 1.9.

SERVICE MANUAL

Fig. 1.9 Carriage Motion Control

1-10

SERVICE MANUAL

1.2.4. Maintenance Station Operation

The maintenance station operation consists of spitting, wiping, capping, and purging.
Table 1.1 shows a summary of maintenance operation for various printer states.

Printer State Spitting Wiping Capping

Power-on 204 2 1

Table 1.1 Summary of Maintenance Operations

THEORY

Mechanical

Beginning of print job 204

(after wiping)

Between pages of continuous
printing

After 6 pages of continuous
printing

After 50 seconds of printing
on the same page

Purging 6,000

Ink cartridge change 204

If no cartridge motion for
more than 30 seconds

Power-off 0 0 0

12 1 0

204

(after wiping)

12

(after wiping)

(after wiping)

(after wiping)

011

10

10

10

11

11

1-11

THEORY

Mechanical

1.2.4.1. Spitting
Spitting is performed at machine power-on, after uncapping from the maintenance

station to clear dormant nozzles, and during the printing process to ensure that
infrequently used nozzles are available when required to print. There must also be
spitting after a wipe cycle, except when the printhead is going to the cap position;
otherwise wiping causes distorted printing if the wiper has experienced any wear.

The trough below he print line is intended to capture the ink during a spit cycle when no
paper is present in the print area. The cup around the wiper is used when spitting is
required and paper is present in the print area. Spitting with paper in print area occurs
when a single page requires longer than 50 seconds to print. All spitting occurs in
trough. At power on, any paper in the print area is ejected.

SERVICE MANUAL

Fig. 1.10 Print Maintenance Operation - Spitting

1-12

SERVICE MANUAL

1.2.4.2. Wiping
Wiping of the print head occurs when the cartridge moves across the wiper (in either

direction). The printhead is wiped (twice) when power is turned on, when beginning a
print job (after the print head has been capped for more than four minutes), after six
pages of continuous printing, after 50 seconds of printing on the same page, and after
purging or changing the ink cartridge.

THEORY

Mechanical

Fig. 1.11 Print Maintenance Operation - Wiping

1-13

THEORY

Mechanical

1.2.4.3. Capping
Capping occurs by the movement of the carriage assembly to the maintenance station,

which moves the MS carriage up to the ramp to align the rubber cap with the ink jet
nozzles. The rubber cap prevents the ink from drying and causing the printhead to clog.
The printer will automatically cap the printhead when the system is powered on, when
no data is received for 30 seconds, and after purging or ink cartridge change.

SERVICE MANUAL

1.2.4.4. Purging
The purging function of the maintenance station is a combination of the wipe, cap, and

spit operations. This initiates a sequence of 6,000 spits of each nozzle, in order to clear
clogged ink from the nozzles. The ink is captured in the trough located below the print
line. Purging is user-activated by pressing
keyboard. See 3. "Cleaning the Print head" in Chapter 5, MAINTENANCE, for
instructions.

Fig. 1.12 Print Maintenance Operation - Capping

CODE + SHIFT + INK CHG

1-14

from the

SERVICE MANUAL

1.2.5. Sensors

There are two sensors in the printer assembly: the carriage home position sensor (leaf
switch assembly, attached to the right end of the CA frame) and the paper end sensor
(attached to the bottom of the PF base at the right rear).

1.2.5.1. Carriage Home Position Sensor
Upon power-up of the system or when the carriage is reset, the carriage moves to the

right end of the printer assembly and activates the home position sensor (leaf switch
assembly). See Fig. 1.13.

THEORY

Mechanical

Fig. 1.13 Carriage Home Position Sensor

1-15

THEORY

Mechanical

1.2.5.2. PE Sensor
PE sensor detects when the trailing edge of the paper passes the knob of PE sensor.

PE sensor is 1C-1P Switch (normal open.) See Fig. 1.14.

SERVICE MANUAL

Fig. 1.14 PE Sensor Mechanism

1-16

SERVICE MANUAL

1.3. INK CHG (Ink Change) Functions

There are two operator-initiated printer maintenance functions available from the
keyboard: ink cartridge replacement and automatic printhead cleaning (purging).

1.3.1. Ink Cartridge Installation/Replacement

There is an ink cartridge installation/replacement function available from the keyboard.
Pressing the key combination
maintenance station to the right end of the printer assembly. Pressing RETURN after
installing or replacing the ink cartridge initializes the system: the cartridge activates the
home position sensor switch and moves the printhead back to the maintenance station.
See Chapter 5, MAINTENANCE, for ink cartridge replacement instructions.

1.3.2. Automatic Print head Cleaning (Purging)

CODE + INK CHG

THEORY

Mechanical

moves the printhead from the

With the ink cartridge installed, pressing the key combination

initiates print head purging. See Chapter 5, MAINTENANCE, for the instructions

CHG

to manually clean the print head.

CODE + SHIFT + INK

1-17

THEORY

Mechanical

2. Keyboard

The keyboard assembly consists of the keyboard panel and keys, the FPC (flexible
printed circuit) board, and the keyboard base plate.

SERVICE MANUAL

Fig. 1.15 Keyboard Assembly

1-18

SERVICE MANUAL

The key tops and key stems are assembled in the keyboard panel. The FPC (flexible
printed circuit) board with rubber contacts is fitted to the base plate. See Fig. 1.16.

The FPC board is a single sheet of film (FPC) on which an electrode pattern is printed in
layers. When the key top is pressed, the key actuator presses the rubber contact; the
conductive part of the contact connects both of the electrodes to output the
predetermined signal for the key.

THEORY

Mechanical

Fig. 1.16 Key Top/Key Stem Assembly

1-19

THEORY

Mechanical

3. LCD

The LCD (Liquid Crystal Display) module is secured inside the upper cover by the LCD
bearing at one end and the hinge assembly at the other end so that it can rotate up and
down.

From the closed position, the LCD can be tilted up as much as approximately 132°. The
hinge assembly is the friction type holder that holds the LCD at whatever angle the user
sets within a range approximately 31° from the upright position.

Contrast adjustment varies depending on the model, as indicated below.
<DP-525CJ/LW-800ic, DP-530CJ/LW-810ic, LW-810icBL>
The slide type LCD volume knob located on the right side of the LCD upper cover is

used to adjust the contrast.

<DP-540CJ, DP-550CJ/LW-840ic>

SERVICE MANUAL

The LCD volume located on the left side of the bottom cover is used to adjust the
contrast.

1-20

SERVICE MANUAL

THEORY

Mechanical

Fig. 1.17 LCD Unit Installation in the Upper Cover

1-21

THEORY

Mechanical

<DP-525CJ/LW-800ic>

SERVICE MANUAL

Fig. 1.18 LCD of DP-525CJ/LW-800ic

1-22

SERVICE MANUAL

<DP-530CJ/LW-810ic, LW-810icBL>

THEORY

Mechanical

Fig. 1.19 LCD of DP-530CJ/LW-810ic and LW-810icBL

1-23

THEORY

Mechanical

<DP-540CJ, DP-550CJ/LW-840ic>

SERVICE MANUAL

Fig. 1.20 LCD of DP-540CJ, DP-550CJ/LW-840ic

1-24

SERVICE MANUAL

CHAPTER 2 ELECTRICAL THEORY

1. System Configuration

The major electronic component parts of the machine are shown in Fig. 2.1.

1.1. Main PCB (Printed Circuit Board)

The main PCB controls the entire system including the LCD, ink cartridge, and the
motors in the printer.

The motors and the ink cartridge are driven by +24 VDC, and the CPU and other
devices are driven by +5 VDC.

1.2. Switch PCB (Printed Circuit Board)

Receiving power from the AC adaptor, the switch PCB supplies voltage to the main
PCB, through the power switch and the fuse.

THEORY

Electrical

1.3. Keyboard FPC (Flexible Printed Circuit)

The keyboard FPC has electrodes arranged in a matrix circuit pattern. The keyboard
status is sent from the FPC to the main PCB.

1.4. FDD (Floppy Disk Drive) Module

The FDD can read and write information supplied to the main PCB. The FDD is driven
by +5 VDC.

1.5. LCD (Liquid Crystal Display) Module

The LCD PCB contains the driver for the dot matrix of the LCD on which various
information is displayed. The CFL backlight (Models: DP-550, LW-810icBL, and LW­840ic) is driven by +5 VDC from the main PCB.

2-1

THEORY

Electrical

SERVICE MANUAL

Fig. 2.1 Major Electronic Component Parts

2-2

SERVICE MANUAL

2. Ink Jet Printer Configuration

The following describes the operation of the ink cartridge, motors and other
components.

2.1. Ink Cartridge

An ink cartridge contains both ink and the print head which has 56 nozzles and prints at
a resolution of 300 dpi.

2.2. Carriage Motor

The carriage step motor drives the carriage right and left with precision motion control.

2.3. Line Feed Motor

The line feed motor feeds the paper forward and in reverse.

THEORY

Electrical

2.4. Carriage Home Position Sensor

The carriage home position sensor is mounted on the right of the CA frame. It detects
the carriage home position to synchronize the carriage position and motor phase.

2.5. PE (Paper End) Sensor

The PE sensor detects whether or not paper is in the printer. The PE sensor is located
at the right rear of the bottom of the PF base.

2-3

THEORY

Electrical

3. Power Supply Circuit

3.1. Configuration

Fig. 2.2 shows the power supply circuit.
The power supply section converts the unstable input (PWR) supplied from the switch

PCB into stable +24 VDC (for motors and print head) and +5 VDC (for logic).
A 2-channel switching regulator IC (#4) converts unstable input into stable output.

SERVICE MANUAL

Fig. 2.2 Power Supply Circuit

2-4

SERVICE MANUAL

3.2. +24V Generator

The timing chart of the +24V generation circuit during idling is shown in Fig. 2.3.
Switching Q6 by #4 at 100 kHz boosts the input to a stable +24V.
Energy is accumulated in L1 while Q6 is ON and the power is transmitted to the output

side by the back electromotive force generated from the moment Q6 is turned OFF.
Stabilization to +24V is achieved by changing the ON-OFF duty ratio of Q6.

THEORY

Electrical

3.3. +5V Generator

The timing chart of the +5V generation circuit during idling is shown in Fig. 2.4.
Switching Q12 by #4 at 100 kHz reduces the input voltage to a stable +5V.
While Q12 is ON, energy is supplied to L3, C31, and load. The energy accumulated in

L3 is supplied to load through D2. Stabilization to +5V is achieved by changing the ON­OFF duty ratio of Q6.

Fig. 2.3 Timing Chart of +24V Generation Circuit

Fig. 2.4 Timing Chart of +5V Generation Circuit

2-5

THEORY

Electrical

4. Reset Circuit

4.1. Configuration

The reset circuit is shown in Fig. 2.5. The reset signal (MRST) used to initialize the
system is generated using the leading and trailing edges of the +5V voltage.

The reset signal is input to the following devices.

SERVICE MANUAL

Device Pin

CBIC (#8) 17
Printer drivers (#2, #3) 5

Fig. 2.5 Reset Circuit

2-6

SERVICE MANUAL

5. CBIC and Peripherals

5.1. CBIC #8

CBIC (#8) is a Cell-based IC in which logic circuits for controlling peripherals are
integrated with the CPU core. With the functions incorporated in it, CBIC (#8) controls
all the functions of the system including printer control and control of the LCD display.

5.2. Main ROM (#11, #12)

Installation of a maximum of 8 Mbytes (32 Mbits x 2 pcs.) of ROM is possible. The
capacity of ROM installed in the machine is determined by whether or not the chip
resistor R71 is installed.

R71 installed: 32 Mbit ROM
R71 not installed: 16 Mbit ROM

THEORY

Electrical

5.3. Main RAM (#9, #10)

The following RAM can be installed at #9 and #10.

#9: 16 Mbit DRAM
#10: 4 Mbit DRAM

Note that simultaneous installation of RAM at #9 and #10 is not allowed.

5.4. Video RAM (#6)

The capacity of the video RAM used to retain the data to be displayed on the LCD is
256 Kbit. It secures the display area for different sizes of LCDs, from 480 x 64 dots to
640 x 400 dots.

The RAM area not necessary for the LCD display can be used as the work area.

5.5. Printer Driver Circuits (#2, #3, Q1 to Q4, and Q23 to Q26)

The printer driver circuits convert the motor phase driver signals output from CBIC (#8)
to +24V drive signals, which are output to the motors and ink cartridge.

5.6. FDC (Floppy Disk Controller)

The FDC controls floppy disk drive access through the FDD drive circuit.

2-7

THEORY

Electrical

5.7. Clock Circuit

Four different clock circuits shown in Table 2.1 are incorporated in the main PCB.

SERVICE MANUAL

Table 2.1 Clock Circuit

Clock Circuit Frequency Function

16MHz XT2 is the standard

clock for FDD control;
it inputs for #5 (pins
25, 26).

18MHz XT1 is the standard

clock for FDD control;
it inputs for #8 (pin

167).

5.8. Buzzer Drive Circuit

The buzzer drive circuit is shown in Fig. 2.6. A 4 kHz pulse of 50% duty is output from
port BUZ (pin 25) of CBIC (#8) when buzzer operation is needed.

The piezoelectric element in BZ1 generates sound on reception of this pulse. The
output from port BUZ is Hi-Z when the buzzer is not in operation.

20MHz XT3 is the standard

clock for printer control
and other several
timing; it inputs for #8
(pints 14, 15).

14.74MHz XT4 is the standard
clock for CPU core; it
inputs for #8 (pints 94,

95).

Fig. 2.6 Buzzer Drive Circuit

2-8

SERVICE MANUAL

5.9. Country Specification Change-over

The country specification change-over circuit is shown in Fig. 2.7. The country
specification is recognized by the CPU by sensing solder on the solder points.

THEORY

Electrical

Fig. 2.7 Country & Model Specification Change-over Circuit

2-9

THEORY

Electrical

5.10. RS-232C I/F Circuit

The RS-232C I/F circuit is shown in Fig. 2.8. The driver IC (#1) converts the signal level
(+5V – ±0V) on the main PCB to the RS-232C signal level in the external line and vice
versa.

SERVICE MANUAL

Fig. 2.8 RS-232C I/F Circuit

2-10

SERVICE MANUAL

6. Printer Control

6.1. Ink Jet Head Control

The ink jet head drive circuit is shown in Fig. 2.9. The ink jet head has 50 active
nozzles (monochrome). Two addressable multiplexing printer drive circuits (#2, #3)
activate the nozzles for printing. Custom circuitry controls the timing and
synchronization of ink deposited as the cartridge moves across the paper in printing.
The same system controls ink jet head maintenance (spitting into the trough).

THEORY

Electrical

Fig. 2.9 Ink Jet Head Drive Circuit

2-11

THEORY

Electrical

6.2. Carriage Motor Control

The carriage motor control circuit is shown in Fig. 2.10. +24 VDC is supplied to the
motor through connector CN3, pin 5. Motor phases A, B, C, and D are driven by the
CBIC (#8) through pins 150 - 153, respectively. The outputs of the CBIC turn darlington
transistors Q1 - Q4 on and off, which in turn affect the motor phases.

SERVICE MANUAL

Fig. 2.10 Carriage Motor Drive Circuit

2-12

SERVICE MANUAL

6.3. Line Feed Motor Control

The line feed motor drive circuit is shown in Fig. 2.11. The line feed motor is powered
by +24 VDC. Each of he four phases of the motor is excited when CBIC (#8), via ports
LF-A, B, C, and D, outputs to turn on the darlington transistors Q23 - Q26.

This provides a path to ground through the transistor, which allows current to flow.
When the printer gate array outputs a LOW, the transistor remains off.

THEORY

Electrical

Fig. 2.11 Line Feed Motor Drive Circuit

2-13

THEORY

Electrical

6.4. Carriage Home Position Sensor

The carriage home position sensor circuit is shown in Fig. 2.12. The HIGH/LOW status
of the sensor is read by pin 164 of the CBIC (#8). The signal goes LOW when the
carriage reaches the home position.

Fig. 2.12 Carriage Home Position Sensor Circuit

6.5. PE Sensor

The PE sensor detection circuit is shown in Fig. 2.13. The HIGH/LOW status of the PE
sensor is read by pin 165 of the CBIC (#8). The signal is HIGH if there is no paper at
the sensor position.

SERVICE MANUAL

Fig. 2.13 PE Sensor Detection Circuit

2-14

SERVICE MANUAL

7. Switch PCB

7.1. Configuration

The Switch PCB is installed between the AC adaptor and the main PCB to turn the
power on and off and protect devices at the occurrence of an alarm, etc.

Fig. 2.14 shows the external view of the switch PCB and Fig. 2.15 the switch PCB
circuit.

THEORY

Electrical

Fig. 2.14 External View of the Switch PCB

Fig. 2.15 Switch PCB Circuit

2-15

THEORY

Electrical

8. Keyboard System

8.1. FPC Operation

The keyboard is a flexible printed circuit (FPC) board on which the circuit pattern and
electrodes are printed. When a key is pressed, the key stem is forced down until the
carbon-type conductive silicone rubber makes a contact with the FPC electrode and
electricity is conducted. See Fig. 2.16.

SERVICE MANUAL

Key Actuator

Contact Rubber

Carbon Electrodes

Carbon Silicon Conductive Rubber

FPC Board

Base Plate

Fig. 2.16 Key/FPC Operation

2-16

SERVICE MANUAL

8.2. Keyboard Scan

Fig. 2.17 shows the pattern from wiring electrodes on the board (this figure shows only
simplified wiring for ease of explanation and is slightly different from the actual wiring).
Refer to Fig. 2.17 to understand the keyboard scanning operation described. When a
key is not pressed, continuity does not exist in any combination of the matrix (e.g. X1
and Y1 or X2 and Y2). For example, if key [A] is pressed, continuity will exist only in X2
and Y3, but not between any other pairs of points which are left in the OFF status. In
other words, if continuity exists between X2 and Y3, it means that key [A] is being
pressed.

THEORY

Pattern Circuit

Pattern Circuit

Electrical

Fig. 2.17 Electrode Wiring

2-17

THEORY

Electrical

8.3. Keyboard Control Circuit

The keyboard control circuit is shown in Fig. 2.18.
The matrix pattern on the keyboard FPC controls port 7 (0:7) of CBIC (#8) according to

data signals KO0 through KO8. The LOW level signals are output to output lines KO0
through KO8. The electrode wiring is scanned line by line. The result of scanning is
input to P70 through P77 of CBIC (#8). CBIC (#8) detects which key has been pressed.
The key matrix given in Fig. 2.19 corresponds to the key arrangement shown in Fig.

2.20.

SERVICE MANUAL

Fig. 2.18 Keyboard Control Circuit

2-18

SERVICE MANUAL

THEORY

Fig. 2.19 Keyboard Matrix

Electrical

Fig. 2.20 Keyboard Symbols (Corresponding to Keyboard Matrix in Fig. 2.19)

2-19

THEORY

Electrical

9. LCD Module

The block diagram of the LCD display operation is shown in Fig. 2.21. CBIC (#8) on the
main PCB outputs the LCD module control signals to the LCD module. The LCD drive
voltage (VEE) is generated by DC-DC convertor by the pulses output from CBIC (#8).
Display data, the data written to the SRAM (#6) that functions as Video RAM is always
sent to the LCD module as 4-bit parallel data.

SERVICE MANUAL

Fig. 2.21 LCD Display Operation Block Diagram

2-20

SERVICE MANUAL

9.1. LCD Control

The CBIC (#8) controls the LCD control signals and the SRAM access.
The display data written to the SRAM (#6) is read by the CBIC (#8) in regular intervals,

converted into the 4-bit parallel data by the CBIC (#8) and then sent to the LCD module.
Black and white of the display data are inverted by connecting the R55 (#8 REV
terminal). Connect the R55 if the transmission type LCD is used.

The timing of display control signals differs according to the LCD type. The timing is set
by the status of the DMODE (3:0) terminal in the CIBC (#8) in the reset state and by the
setting in the program after the reset is canceled. An example of the control signal
timing chart is shown in Fig. 2.22.

THEORY

Electrical

Fig. 2.22 Example of Control Signal Timing Chart

9.2. LCD Module

The LCD modules used in the respective models are shown in Table 2.2. The control
signal timing and drive voltage (VEE) differ according to the LCD module.

Table 2.2 Table of LCD Modules

Specification No. of Horizontal

Model Name
DP-525CJ LW-800ic 480 64 Reflective no –17.5 to –14.5
DP-530CJ LW-810ic 480 128 Reflective no –17.5 to –14.5

LW-810icBL 480 128 Transflective yes –17.5 to –14.5
DP-540CJ 640 400 Reflective no +22 to +30
DP-550CJ LW-840ic 640 400 Transmissiveyes +26 to +37

Dots

Note: VEE voltage is the values measured at connectors CN7 and CN8.

No. of
Vertical Dots

Panel Type Backlight VEE (V)

2-21

THEORY

Electrical

9.3. LCD Drive Voltage (VEE) Generation Circuit

The polarity of the LCD drive voltage (VEE) differs according to the LCD module.
Fig. 2.23 shows the circuit for the LCD module driven by the minus VEE voltage. The

+5 VDC source voltage is switched continuously by the 20 kHz pulses from CBIC (#8) to
energize L5. The reverse voltage generated by L5 is rectified by D6 and regulated by
ZD5. The ZD5 determines the VEE voltage (about -16 V).

The LCD module driven by the plus VEE voltage uses the circuit shown in Fig. 2.24.
The +24 VDC source voltage is switched continuously by the 90 kHz pulses from CBIC
(#8) to energize L2. The voltage generated by L2 is rectified by D5 and regulated by
ZD4 and ZD6. The ZD4 and ZD6 determine the VEE voltage.

VEE voltage is adjusted by turning VR1.

SERVICE MANUAL

Fig. 2.23 LCD Drive Voltage Generation Circuit (Minus Voltage VEE)

Fig. 2.24 LCD Drive Voltage Generation Circuit (Plus Voltage VEE)

2-22

SERVICE MANUAL

9.4. Power Supply for CFL Backlight

The CFL backlight circuit consists of the control circuit that turns ON/OFF the CFL and
the inverter PCB.

The ON/OFF status of the CFL is controlled by the CFLON terminal of the CBIC (#8).
The inverter PCB converts +5V to AC voltage to drive the CFL tube. The type of

inverter PCB differs according to the LCD.
Fig. 2.25 shows the CFL backlight circuit.

THEORY

Electrical

Fig.2.25 CFL Backlight Circuit

2-23

THEORY

Electrical

10. FDD (Floppy Disk Drive) Control

10.1. FDD Configuration

The FDD consists of two sections: the FDD controller and the FDD module. The FDD
controller circuit controls the contents to be received and stores the data in the FDD
module. The FDD module drives the motors, sensors, and magnetic head. The
interface signals between the FDD and the FDC are shown in Table below:

Table.2.3 FDC(#5) and FDD Module Links (Interface Signals)

Signals Pin No. Function

Read/Write
Circuits

Motor Drive
Circuit

Status Check WRITE PROTECT 28

DRIVE SELECT Ø 10 12

WRITE GATE 24

WRITE DATA 22

READ DATA 30

SIDE1 SELECT 32

DC
MOTOR

STEP

MOTOR

16

ON
STEP 20

MOTOR

DIRECTION
SELECT

18

INDEX 8

TRACKØØ 26

DISK CHANGE 34

SERVICE MANUAL

This signal is set to LOW when the FDD unit is
opening (except for the DC Motor).

When this signal is set to LOW, data can be written
by the WRITE DATA signal. When this signal is set
to HIGH, the READ and STEP operations are
enabled.

Data is written at the falling edge of this signal while
the WRITE GATE signal is LOW.

This signal indicates the polarity data read by the
head.

This signal is used to select the head:

LOW: Head 1
HIGH: Head 0

This signal becomes LOW, starting the DC motor,
when a disk is set in the drive. Setting this signal to
HIGH or removing the disk stops the DC Motor.

This signal sets the head in the direction designated
by the DIRECTION signal.

This signal designates the movement of the
read/write head:

LOW: Inward to the disk's center
HIGH: Outward from the disk's center.

When this signal is LOW, either there is no disk in
the drive or the disk in the drive is write-protected.

This signal indicates the beginning of a track by
outputting one pulse in each rotation of the disk.

When this signal is LOW, the head is located at track
00 (the outside track).

Otherwise, the signal is HIGH.
When this signal is LOW, there is no disk in the drive.

2-24

SERVICE MANUAL

10.2. FDD Operation

10.2.1. Basic Operation

CBIC(#8) writes commands to FDC(#5), and the FDC(#5) controls the FDD in
accordance with these commands and reads/writes data.

See Fig. 2.26.

10.2.2. Interface between CBIC (#8) and FDC (#5)

If CBIC(#8) accesses an internal register other than the data resister in FDC (#5), the
normal read/write operation will be performed.

If CBIC(#8)transmits data to or receives data from FDC (#5), DMA communications will
be performed using the DMA function of CBIC(#8).

CBIC(#8) resets FDC(#5),detects the density signal which indicates whether the floppy
disk is a 2DD or 2HD, and output to FDC(#5).

THEORY

Electrical

Fig.2.26 FDD Block Diagram

2-25

THEORY

Electrical

10.3. FDD Module

The FDD Module is composed of the motor, sensor, magnetic head, and the IC that
drives them. The FDD Module is controlled by the FDC (#5) of the MAIN PCB.

10.3.1. Read/Write Circuit

In read operation, the circuit amplifies the analog signals picked up by the magnetic
head and converts the analog signal to serial digital pulses. The serial pulses are then
transmitted to the FDC (#5) and decoded to parallel digital data.

In write operation, the circuit controls the current at the magnetic head according to the
serial digital pulses from the FDC #5.

10.3.2. Motor Drive Circuit

The motor drive circuit consists of two parts: a DC motor drive circuit and a stepping
motor drive circuit.

The DC motor drive circuit controls the DC motor, which rotates the spindle according to
the MOTOR ON signal from the FDC. The stepping motor drive circuit controls the
stepping motor, which operates the magnetic head unit according to the "STEP" and
"DIRECTION SELECT" signals from the FDC #5.

SERVICE MANUAL

10.3.3. Sensor Circuits

The following sensor circuits detect the status of the FDD:

1. Write Protect Sensor
When a write-protect notch on a disk is set to the write-protect position, the "WRITE

PROTECT" signal becomes LOW. A micro-switch is used for detection.

2. Index Sensor
The "INDEX" signal shows the beginning of a track; when the beginning of a track is

detected, the "INDEX" signal becomes LOW. A magnetic sensor is used for
detection.

3. Track00 Sensor
When the magnetic head is positioned in track 0 on a disk, the "TRACK 00" signal

becomes LOW. A photo sensor is used for detection.

2-26

SERVICE MANUAL

4. Disk-in Sensor
When a disk is inserted in the FDD, this sensor outputs a LOW level signal (HIGH

when no disk).
The output of the sensor is connected to the controller and sent as a "DISK

CHANGE" signal that shows whether a disk is changed; when a disk is changed, the
"DISKCHANGE" signal becomes LOW.

Once the "DISK CHANGE" signal becomes LOW, it remains low until the "STEP"
signal is received from the FDC #5.

THEORY

Electrical

2-27

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SERVICE MANUAL

PART II REPAIR

CHAPTER 3 TROUBLESHOOTING

1. Introduction

This chapter explains troubleshooting procedures for the word processor. Since it is
impossible to troubleshoot all instances of a problem, only a limited number of cases
are presented. Thorough understanding of the procedures given in each section is
essential for efficient troubleshooting, and can provide a good insight to the problem.

2. Precautions

2.1. Personal Safety

Troubleshooting

WARNING:

In addition to any specific warnings as described above, be sure to take the following
precautions for your personal safety:

• Unplug the AC adapter from the AC outlet before removing the covers and PCBs, or

before making any mechanical adjustments.

• Unplug the AC adapter from the AC outlet before checking continuity.

• When disconnecting a connector, grasp it firmly. Do not pull on the connector's lead

wires. If the connector has a lock mechanism, unlock it before trying to disconnect it.

If there is chance of electrical shock, this symbol will precede any
instructions in this manual. Follow the safety advice carefully!

2.2. Handling ESD-Sensitive Parts

Many electronic products use parts that are known to be sensitive to electrostatic
discharge (ESD). To prevent damage to ESD-sensitive parts, observe the caution
symbols throughout these instructions, as well as the additional precautions below.

3-1

Troubleshooting

REPAIR

SERVICE MANUAL

CAUTION:

In addition to the usual precautions, such as turning off power before removing circuit
boards:

Keep the ESD-sensitive part in its original shipping container (a special "ESD bag")

•

until you are ready to install it.
Do not place the ESD-sensitive part on the machine cover or on a metal table; if you

•

need to put down the ESD-sensitive part for any reason, first put it into its special bag.
When holding ESD-sensitive parts, limit your body movement to prevent an increase

•

of static electricity from clothing fibers, and furniture.
Hold the ESD-sensitive part by its edge connector shroud (cover); do not touch its

•

pins. If you are removing a plugable module, use the correct tool.
Be extra careful in working with ESD-sensitive parts when cold-weather heating is

•

used, because low humidity increases static electricity.

Electrostatic Discharge Hazard
Wear an anti-static wrist strap with ground wire to prevent damage to

sensitive electronic components.

Prevent ESD-sensitive parts from being accidentally touched by other personnel.

•

Install machine covers when you are not working on the machine, and do not put
unprotected ESD-sensitive parts on a table.

If possible, keep all ESD-sensitive replacement parts stored in a grounded metal

•

cabinet (case) until ready for use.

3. Checks Before Repair

CAUTION:

Check the following possible causes before attempting more extensive repairs to the
machine:

Electrostatic Discharge Hazard
Wear an anti-static wrist strap with ground wire to prevent damage to

sensitive electronic components.

3-2

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SERVICE MANUAL

Run the appropriate Self Test operation (from the software) for the suspected problem

•

before attempting any mechanical or electrical troubleshooting.
Supply voltage: Check the AC input voltage and DC supply voltage for all sections.

•

Make sure they meet specified voltage values.
Connectors: Check all connectors and make sure they are tight.

•

Fuses: Check for blown fuses (F1 and the thermo-fuse inside the AC adapter).

•

NOTE:

In the logic control circuit, it is difficult to isolate faulty points in areas connected tot he

•

CPU by the address bus or the data bus. If a suspected problem involves the address
bus or data bus, first check the solder bridge and the cut circuit pattern. If a faulty point
cannot be isolated, replace the peripheral devices or the PCB.

4. Checks After Repair

After completing a repair, check to confirm that the trouble has been eliminated. Also,
record the troubleshooting procedures used for reference.

Troubleshooting

3-3

Troubleshooting

5. Troubleshooting Flow Charts

Power ON

REPAIR

SERVICE MANUAL

LCD operating

correctly?

YES

Carriage (print head)

moves?

YES

Printer home position

detected?

YES

Keys work properly?

YES

Prints normally?

NO

NO

NO

NO

NO

Problem No. 1

Problem No. 2

Problem No. 3

Problem No. 4

Problem No. 5

YES

Line Feed operates

Paper feeds normally?

correctly?

YES

A

Fig. 3.1 Troubleshooti ng Fl owchart

NO

Problem No. 6

3-4

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SERVICE MANUAL

Troubleshooting

A

Does the buzzer sound

when an invalid key is

pressed?

YES

Does the LCD operate?

YES

Does the LCD display

correctly?

YES

Does the unit print

when paper is set, or print when

no paper is set?

YES

Does the FDD operate

correctly?

NO

NO

NO

NO

NO

Problem No. 7

Problem No. 8

Problem No. 9

Problem No. 10

Problem No. 11

YES

Does the

fax/modem (optional)

Line Feed operates

operate properly?

correctly?

NO

Problem No. 12

YES

Does an error message

appear on the display?

YES

Problem No. 13

NO

END

Fig. 3.2 Troubleshooti ng Fl ow char t ( cont inued)

3-5

Troubleshooting

SERVICE MANUAL

6. Failure Analysis

The following table lists the failure problems for troubleshooting all basic systems. See
the Troubleshooting Tables on the following pages for a troubleshooting protocol.

Table 3.1 Failure Analysis

No Problem

1 Nothing happens when the power is switched on (Nothing appears on the LCD).
2 When the power is switched on, the LCD display operates but the carrier does not

return to its home position.

3 When the power is switched on, the carrier moves to the right but cannot detect

its home position (i.e., the home position indexing mechanism is faulty).
4 Keys malfunction (do not insert characters or insert wrong characters)
5 Printing results abnormal (various unsatisfactory printing results)
6 The line feed (LF) motor does not rotate normally.

REPAIR

7 The buzzer does not sound.
8 Power in on, but nothing appears on the LCD.
9 LCD displays operates, but data displayed is incorrect (does not match input).

10 Word Processor prints when no paper is set, or will not print when paper is set

(Paper End Sensor malfunction).

11 The FDD does not operate correctly.
12 Communication function (optional fax/modem) does not work or does not work

properly.

13 An error message appears on the display.

3-6

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SERVICE MANUAL

Troubleshooting Tables

Troubleshooting

1

Problem:

Points to Check Probable Cause Corrective Action Repair

Is (at least) about +16 V present on
the output plug if the AC adapter?

Is fuse F1 on the Switch PCB OK? Blown fuse Replace the Fuse.
Are harnesses CN1 on the Switch

PCB properly connected?
Is about +16V present at CN1 on the

Switch PCB?
Is +5V present on the Main PCB? Defective ZD7 or Q12

Problem:

2

Points to Check Probable Cause Corrective Action Repair

With motor cable disconnected, is
+24 V present at CN3, pin 5 on the
Main PCB?

Is resistance value across each of
the phases and COM terminal (pin

5) of the carriage motor correct?
(about 45Ω) Phases → ;(5-1); B(5-

2); ‚b(5-3); D(5-4)
Are carriage motor drive pulse

output from pin 150-153 of #8 just
after power is switched on ? (Use
an oscilloscope.)

Is output at the pin of transistors Q1­Q4 on and off according the drive
pulses indicated above?

Does the carriage motor
occasionally stall?

Nothing happens when the power is switched on (nothing appears on the LCD).

Defective AC adapter Replace the AC

adapter.

Harnesses improperly
connected.

Defective Switch PCB Replace the Switch

(Main PCB)

When the power is switched on, the LCD display operates but the carrier does not
return to its home position.

Defective Q6 (Main
PCB)

Broken wire in the
carriage motor
assembly (broken wire
in the carriage motor)
(defective connector)

Defective #8 (Main
PCB)

Defective transistor
Q1-Q4 or circuit on the
Main PCB

Incorrect motor phase
at home position (start
up).

Replace the Switch
PCB.

PCB.
Replace the Main

PCB.

Replace the Main
PCB

Replace carriage
motor assembly.

Replace the Main
PCB.

Replace the Main
PCB.

Adjust motor phase at
home position (see
Chapter 4 "INK JET
PRINTER
ASSEMBLY").

Rework the
connectors.

Replace ZD7,
Q12.

Replace Q6.

Replace #8.

Replace Q1­Q4.

Problem:

3

Points to Check Probable Cause Corrective Action Repair

Is the carriage index (home position)
switch open?

When the power is switched on, the carrier moves to the right but cannot detect its
home position.

CA index switch is not
adjusted correctly.

3-7

Readjust.

Troubleshooting

Points to Check Probable Cause Corrective Action Repair

Does the signal level at pin 1 of
CN13 remain HIGH when the
carriage index switch is closed?

Is the carriage index switch
connected to CN13?

Broken wire in the
carriage index switch
assembly

Incorrect connection Reconnect.

Replace the carriage
index switch assembly
(after confirming
discontinuity).

REPAIR

SERVICE MANUAL

4

Problem:

Points to Check Probable Cause Corrective Action Repair

Is the key top and the key actuator
correctly mounted?

Is the keyboard FPC securely
connected to Main PCB CN12?

When a bad key is pressed, does
the matrix row in which the pressed
key is connected go LOW in
synchronization with the output
timing of output drive #8?

Is solder present at the correct
country specification change-over
solder point?

5

Problem:

Keys malfunction (do not insert characters or insert wrong characters)

[Abnormal Printing]

• Voids in characters • Light print • Prints off the page

• Prints satellites • Carrier moves, but does not print

• Print head dries out prematurely • Vertical alignment off

• Ink smearing • Vertical streaks on paper

• Print lines crowded • Gaps or overlapped areas in print

• Will not print in color • Colors will not print correctly.

Faulty keyboard
assembly

Keyboard PCB not
connected properly.

If YES, faulty Main
PCB.

If NO, faulty keyboard.

Incorrect or faulty
solder point for
specified country
(language)

Replace the
keyboard.

Reconnect.

Replace the Main
PCB.

Replace the
keyboard.

Verify and correct
solder point.

Points to Check Probable Cause Corrective Action Repair

(1) Print Cartridge:

Is the ink cartridge good, and is
it properly installed?

After executing the purge (auto
printhead cleaning) function from
the keyboard
(CODE+SHIFT+INK CHG), are
there still printing problems?

(2) Printhead Carriage Assembly:

Is the flat cable firmly connected
in the Main PCB?

Cartridge empty, dried
out, or not locked in
and aligned with
contacts in carriage.

Dirty or clogged ink jet
nozzles

Loose or worn
printhead flat cable.

3-8

Replace with a new
cartridge, and/or
properly install the ink
cartridge.

Replace the ink
cartridge and run the
Self-Print test, and/or
replace the printer flat
cable.

Reconnect loose flat
cable or replace it.

Replace the ink
cartridge
and/or the
printer flat
cable.

Replace flat
cable.

REPAIR

SERVICE MANUAL

Points to Check Probable Cause Corrective Action Repair

Is these wear or damage to the
ink cartridge head locker, spring,
or carriage assembly?

(3) Maintenance Station:

Is the wiper loose or worn?
Is the cap worn or loose? Defective cap Replace cap.
Is the spring-loaded MS carriage

moving freely?

(4) Paper/Line Feed:

Are there any obstruction in the
paper path?

Is the correct type of paper in
the machine?

Are star-wheels binding? Star-wheels dirty,

Is the main roller assembly
rotating properly?

Does not the line/paper feed
motor rotate normally?

Does the sheet lead edge
contact the frist print roller?

Are the drive gears working
properly?

(5) Color Print (Check Items 1-4

above)
With a color cartridge properly

installed, will the system display
a color selection dialog box, and
then print the file in the color
selected?

Run the Self-test color print test
1 (#2 from the SELF TEST
MENU).

Head locker or spring
worn or damaged:
dirty, worn, or
damaged gold-plated
contacts the printer flat
cable.

Defective wiper Replace wiper.

Obstructions in
carriage path; spring
broken or loose; MS
carriage out of tracks.

Paper jam Clear paper path.

Wrong paper (weight,
size)

worn, or dislodged.
Worn or broken gears,

bearing, defective line
feed motor?

See Problem 6, Line
Feed Motor.

Paper jam, incorrect
paper wt./type; worn
main shaft rollers

Worn, misalign, or
damaged gears.

If no, color detection
circuit (Main PCB) is
defective.

After eliminating items
1-4 (same as
monochrome print),
defective Main PCB.

Remove the cartridge
and clean the
contacts on the flat
cable in the carriage;
Replace the carriage
mechanism.

Remove obstructions,
realign carriage on
tracks, or replace MS
assembly.

Try correct paper.

Replace star-wheel
assembly.

Replace main roller
assembly.

Clear paper path,
install proper wt./type
paper.

Replace the gear
holder assembly
and/or the main shaft
gear.

Replace the Main
PCB.

Replace the Main
PCB.

Troubleshooting

Replace spring,
head locker, or
printer flat
cable.

Replace spring
or MS
assembly.

Replace gears,
bearing, and/or
motor.

Replace main
shaft rollers.

Replace D3,
ZD3, Q16, #8.

3-9

Troubleshooting

REPAIR

SERVICE MANUAL

6

Problem:

Points to Check Probable Cause Corrective Action Repair

Is the LF motor turning activated ? is
it noisy?

Are any motor harness wires
damaged?

Are there binds in the LF motor or
gear train?

Is the LF motor gear loose or worn? Loose motor screws or

Is the resistance between the pin 5
of the LF motor and each phase
normal?(about 60Ω)Phases → A(5-

1); B(5-2);C(5-3); D(5-4)
Are LF motor drive pulses output

from the pin131-134 of #8 when
printing?

Is output at the output pin of
transistors Q23-Q26 on and off
according the drive pulses indicated
above?

The line feed (LF) motor does not normally.

Defective LF motor Replace LF motor.

Defective motor wiring
harness

Worn, dirty, damaged,
or obstructed gear
train, improper gear
backlash

worn LF motor gear
Defective LF motor

(broken motor wire or
defective connector)

Defective #8 (Main
PCB)

Defective transistor
Q23-Q26 or circuit on
the Main PCB

Replace LF motor.

Clean/remove
obstructions. Space
motor from gear.
Replace damaged
gear(s).

Tighten motor screws.
Replace LF motor.

Replace the LF motor
assembly.

Replace the Main
PCB.

Replace the Main
PCB.

Replace #8.

Replace Q23­Q26.

7

Problem:

Points to Check Probable Cause Corrective Action Repair

Are pulses of 4kHz present on one
pin and about 5V present at the
other pin of buzzer BZ1?

8

Problem:

Points to Check Probable Cause Corrective Action Repair

Is the contrast setting correct? Faulty contrast

Is the LCD harness free of
breakage?

Is the correct voltage (about -16V)
applied to the LCD on pin 2 of
connector CN7 of the Main PCB?
(without 640 × 400 LCD)

The buzzer does not sound.

If YES, defective
buzzer

If NO, defective Main
PCB.

Power in on, but nothing appears on the LCD.

adjustment
Broken LCD harness Replace the harness.

Incorrect power supply
voltage to LCD module

Replace the buzzer.

Replace the Main
PCB.

Re-adjust.

Replace the Main
PCB.

Replace #8.

3-10

REPAIR

SERVICE MANUAL

Points to Check Probable Cause Corrective Action Repair

Is the correct voltage (about 25V­36V) applied to the LCD on pin 11 of
connector CN8 of the Main PCB?
(640 × 400 LCD)

Is oscillator XT1 operating correctly?
(Use an oscilloscope to check)

Do the output pulses from MRD of
#8 change?

Troubleshooting

Incorrect power supply
voltage to LCD module

Defective XT1 or #7 Replace XT1,

Defective #8 Replace #8.

Replace the Main
PCB.

#7.

9

Problem:

Points to Check Probable Cause Corrective Action Repair

Is solder present at the correct
Country Specification Change-Over
Solder Point?

Is there an output wave form at each
pin in the connector CN7 or CN8

Is there faulty soldering the LCD
module?

Do the CBIC (#8) MA0-MA14 pulses
change sequentially

Do video RAM (#6) MD0-M7 change
in response to the MA0-MA14
pulses?

10

Problem:

Points to Check Probable Cause Corrective Action Repair

Is the PE(paper end) switch properly
installed?

Is the PE switch lever stuck? Incorrect installation Reinstall.
Is the PE switch damaged? Replace the PE

Does pin 1 of CN14 go LOW when
paper is not set and HIGH when
Paper is set?

Does the switch function abnormally
even though the above signals are
normal?

LCD displays operates, but data displayed is incorrect (does not match input).

Incorrect or faulty
solder point for
specified country
(language)

Defective #8 or solder
bridge

Defective #8 Replace #8.

Defective #6 Replace #6.

Word processor prints when no paper is set, or will not print when paper is set (Paper
End Sensor malfunction)

Incorrect installation Reinstall.

Harness wire break or
defective PE switch

Defective #8 Replace the Main

Verify and correct
solder point.

Replace the Main
PCB.

Replace the LCD
module.

switch.
Replace the harness

or the PE switch.

PCB.

Replace #8.

Replace #8.

3-11

Troubleshooting

REPAIR

SERVICE MANUAL

11

Problem:

Points to Check Probable Cause Corrective Action Repair

Is FDD power harness correctly
connected?

Is FDD ribbon cable correctly
connected?

ERROR on performing the FDD self­test (Since performing this destroys
all data on the disk, always use a
disk containing data whose loss is
not important.)

Is oscillator XT2 operation correctly?
(Use an oscilloscope to check)

12

Problem:

Points to Check Probable Cause Corrective Action Repair

Is the fax/modem cable connected
properly?

Is each level of CN1 signal approx.
±10V?

Do the TXD of the CBIC (#8) signal
change?

Do the RXD of the CBIC (#8) signal
change?

The FDD does not operate correctly

Communication function (optional fax/modem)do not work or do not work properly.

FDD power harness is
not correctly
connected.

FDD power cable is
not correctly
connected.

Defective FDD or FDD
ribbon cable.

Defective FDC (#5)

Defective XT2 Replace XT2.

Faulty/improper
connection.

Defective #1 Replace the Main

Defective #8 Replace the main

Defective #1 or circuit
on the Main PCB

Reconnect. Replace the

FDD power
harness.

Reconnect. Replace the

FDD power
cable.

Replace the FDD or
the FDD ribbon cable,
as req.

Replace the Main
PCB.

Reconnect cable. Replace cable.

PCB.

PCB.
Replace the Main

PCB.

Replace the
FDD or cable.

Replace #5.

Replace #1

Replace #8.

Replace #1.

13

Problem:

Points to Check Probable Cause Corrective Action Repair

(1) "Check printer Press any key to

continue." (After executing print
command) Is the paper path
clear

Is the CA index (home position)
switch working properly?

Is ROM/RAM (#11,#12/#10)
working properly?

An error message appears on the display.

Possible paper jam. Check/clear paper

path

Home position cannot
be detected (defective
index switch)

Defective ROM/RAM
(#11,#12/#10)

See Problem 3,
"Home position Switch
Checks".

Execute the Self-Print
test (in SELF TEST)
and verify that the
ROM/RAM (sum­check) test is normal
(if error on Self-Test,
replace the Main
PCB).

3-12

Replace the
Main PCB

REPAIR

SERVICE MANUAL

Points to Check Probable Cause Corrective Action Repair

(2) "Incorrect spec!"(when power on)

Do the soldering points for the
Country Code Change-Over
circuit match the ROM?

(3) "RAM down" (RAM cannot be

accessed at power on)
Is the RAM installed correctly?

Solder point setting is
wrong, or the ROM
(#11,#12) is incorrectly
mounted.

RAM improperly
installed (e.g. solder
bridge) or defective
RAM(#10).

Replace the Main
PCB.

Replace the Main
PCB.

Troubleshooting

Set the correct
solder point, or
replace the
ROM.

Reinstall/replac
e the
RAM(#10).

3-13

Troubleshooting

REPAIR

SERVICE MANUAL

7.

SELF-TESTS

From the Main Menu, two self-test modes are available:

1. Self-Print
Press the CODE + SHIFT + RETURN keys.

2. Self-Test
Press the CODE + SHIFT + BACKSPACE keys.

7.1. SERIAL NUMBER Input Display

The machine prompts you for the unit serial number after the Self-Test mode is
accessed, but before the test is started:

From the SELF PRINT screen

•

From the SELF TEST menu, after selecting a test, of after pressing the "S" key.

•

SERIAL NO.:

■

Type SERIAL NO. and press RETURN.

Fig. 3.3 Serial Number Entry Display

NOTES:

The maximum number of characters that can be input is 9; alphanumeric keys are the

•

only acceptable input.
The RETURN key can also be pressed without entering a serial number.

•

Pressing CANCEL while the SERIAL NUMBER prompt is displayed cancels any

•

number entered (before pressing RETURN), and returns to the SELF TEST menu.

3-14

REPAIR

g

SERVICE MANUAL

7.2. Self Print Mode

(1) From the Main Menu, press CODE + SHIFT + RETURN. The SELF PRINT display

appears, with the SERIAL NO. input pop-up screen.

(2) Enter the unit serial number and press RETURN (or press RETURN without entering

a number).

(3) A sum check of the MAIN RAM, MAIN ROM and DICTIONARY ROM is then

performed.

Troubleshooting

*****

SELF PRINT

*****

VIDEO RAM Checking... O K. NG.
MAIN ROM

Checkin

... OK. NG.
CG ROM Checking... OK. NG.
DICTIONARY ROM OK .Checking... NG.

MAIN RAM Checking... OK. NG.

(NORMAL) (ABNORMAL)

Fig. 3.4 Self-Print Pattern

NOTES

"OK" is displayed if the checked item is normal ("NG" if there is an error). If the result of

•

all checks is "OK" the carriage is returned and, the self-print ("all character") test is
starts.

If there are any errors in the sum check, self-printing will not start. The buzzer will not

•

sound, but the SELF PRINT screen will remain. It will not be possible to proceed with
any operation (cycle the power switch to reset the system).

The following print format settings are in effect for the test:

•

Font type: Brougham
Font size: 12 point
Type style Normal
Line space: Auto
Left/right margins: 1 - 7.4 inch (with CSF)
Tab setting: None

3-15

Troubleshooting

The following printing pattern is printed:

•

REPAIR

SERVICE MANUAL

LM

1 inch

6.4 inches

RM

[Memory Codes 21(H) to 7E(H) printed]

•

The serial number is printed on the first line (if it was entered), and then 59 lines of

•

characters are printed at 64 characters per line; with each line beginning with one
character from the right of the previous line.

If the CANCEL is pressed while the serial number input screen is displayed, the input

•

character string will not be registered as a serial number and display will return to the
Main Menu screen.

If the SPACE BAR or CANCEL key is pressed during printing, self printing is

•

suspended and the pop-up screen shown below is displayed:

OK to cancel printing?

Use cursor to select and press RETURN.

[YES]

If RETURN is entered while the cursor is located at "YES", self-printing is canceled and

•

[NO]

the display returns to the Main Menu.
If RETURN is pressed while the cursor is located at "NO", self-printing is resumed.

•

3-16

REPAIR

SERVICE MANUAL

Troubleshooting

Fig. 3.5 Results of Self-Print Test

3-17

Troubleshooting

7.3. Self-Test Mode

There are six tests types available in Self Test mode: (1) LCD Display tests, (2) Printer
Checks, (3) Keyboard Test, (4) FDD Tests, (5) PE (Paper Exist), (6) CR (Carriage Reset
to Home Position), and (7) RS-232C Test.

(1) From the Main Menu, press the CODE + SHIFT + BACKSPACE keys, and the menu

shown below displays.

(2) Press the character key for the desired test:

<14-line model and 10 inch VGA model>

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SERVICE MANUAL

SELF TEST MENU

DISPLAY 1
PRINTER 2, 3
KEYBOARD 4, 5, 6
FDD 7, 8, 9, D, E
PE A
CR B
RS-232C C
SERIAL NO. S [XXXXXXXX]
DISK TYPE. T 2DD

Please select the number. Press CANCEL to finish.

<7-line model>

SELF TEST MENU

DISPLAY 1
PRINTER 2 , 3
KEYBOARD 4, 5, 6
FDD 7, 8, 9, D, E

PE A
CR B
SERIAL NO. S [XXXXXXXX]
DISK TYPE. T 2DD

**********

2HD

← →

**********

2HD

← →

Please select the number. Press CANCEL to finish.

Fig. 3.6 Self-Test Menu

3-18

REPAIR

SERVICE MANUAL

NOTES:

Pressing the CANCEL key while the above menu is displayed will return the display to

•

the Main Menu.
The keys that can be used while the SELF Test menu is displayed are:

•

Alphanumeric keys start the test
CODE+SHIFT+INSERT paper insert
CODE+SHIFT+CANCEL line feed
CODE+SHIFT+HELP paper eject
CANCEL returns to the Main Menu

If a serial number has been input, it will be displayed in the brackets to the right of the

•

serial number menu item; if no serial number has been entered, only the brackets will
be displayed.

If there is a problem with the printer, an error message is displayed, and testing will

•

continue without performing the printer test.

Troubleshooting

3-19

Troubleshooting

7.3.1. Display (LCD) Test

There are four display checks available: 1) CHECK, 2) CROSS, 3) BLACK, and 4)

DISP. Q. 5) SLANT LINE
(1) From the Self Test menu, select "1" to open the LCD Test Menu.
(2) Press the number key for the desired display test. The screen displays the selected

test pattern.

<14-line model and 10 inch VGA model>

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SERVICE MANUAL

LCD TEST MENU

1. CHECK

2. CROSS

3. BLACK

4. DISP. Q

5. SLANT LINE

Please select the number. Press CANCEL to finish.

<7-line model>

LCD TEST MENU

1. CHECK

2. CROSS

3. BLACK

Please select the number. Press CANCEL to finish.

Fig. 3.7 LCD Test Menu

**********

**********

4. DISP. Q

5. SLANT LINE

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7.3.1.1. Check Test
The CHECK test displays every other bit as shown below (magnified).
Select "1" from the MENU screen.

NOTE:

Press the space bar and the displayed bit pattern is reversed.

•

1

2 3 4 5 6 7 8 9 10 11 12 13 14

1

2
3
4

Troubleshooting

5
6
7
8

9
10
11
12
13
14
15

Fig. 3.8 CHECK Test Display (magnified)

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Troubleshooting

7.3.1.2. Cross Test
The CROSS test displays the grid pattern shown below (magnified).
Select "2" from the MENU screen.

NOTE:

Press the space bar and the displayed bit pattern is reversed.

•

1

1

2
3
4

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SERVICE MANUAL

2 3 4 5 6 7 8 9 10 11 12 13 14

5
6
7
8

9
10
11
12
13
14
15

Fig. 3.9 CROSS Test Display (magnified)

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SERVICE MANUAL

7.3.1.3. Black Test
The BLACK test checks for missing dots (pixels).
Select "3" from the MENU screen.

NOTE:

Press the space bar and the displayed bit pattern is reversed.

•

Every pixel on the screen is displ ayed.

Troubleshooting

Fig. 3.10 BLACK Test Display

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Troubleshooting

7.3.1.4. Display Q Test
The DISP Q test displays the character "Q" on the entire screen.
Select "4" from the MENU screen.

NOTE:

Press the space bar and the displayed bit pattern is reversed.

•

1 2 3 4 5 6 7 8 91011121314

1

2
3
4

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SERVICE MANUAL

5
6
7
8

9
10
11
12
13
14
15

Fig. 3.11 DISP Q Test Display (magnified)

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SERVICE MANUAL

7.3.1.5. Slant Line Test
The SLANT LINE test displays the pattern as shown below.
Select "5" from the MENU screen. The following screen is displayed.
Upper left corner

NOTE:

Press the space bar and the displayed bit pattern is reversed.

•

If any key other than the key indicated above is pressed, the screen will return to the

•

MENU screen.

Troubleshooting

Fig. 3.12 Slant Line Test Display (magnified)

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Troubleshooting

7.3.2. Print Checks

There are two self-test print checks.

7.3.2.1. Print Test Pattern 1
Purpose: To check that all characters are printed correctly.
From the Self Test menu, select "2" at the MENU screen. When printing is complete,

the display automatically return to the Self Test menu. The diagram (see in Fig. 3.14)
shows which characters should be printed and their locations in reference to each other.
A sample of the printed pattern is shown in Fig. 3.15.

REPAIR

SERVICE MANUAL

*****

PRINTER CHECK

Press CANCEL to go to MENU.

Fig. 3.13 Printer Check #1 (in progress) Display

NOTES

A paper check is performed before printing. If paper is set, the print test is executed; if

•

*****

no paper is set, the ERROR pop-up window is displayed. If you select to continue
printing, paper is automatically inserted by the ACF and to execute the print test.

Pressing the CANCEL key during printing will stop the test (paper is advanced), and

•

return the display to the Self Test menu.
If a serial number has not been input before starting the test, the pop-up window will

•

prompt for the serial number; either enter the serial number, or press RETURN to start
the test. If a serial number is entered, it will be printed on the first line of the test.

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SERVICE MANUAL

0.5 inch

SERIAL NO.: XXXXXXXXX (9 digits)

1/6 inch

1/6 inch

1/6 inch

1/6 inch

Troubleshooting

The 20(H) to EF(H)
characters are printed on
this line (12 point).

Line 1 YELLOW *
Line 2 MAGENTA *
Line 3 CYAN *

The 20(H) to EF(H)
characters are printed on
this line (7 point).

RED*

The 20(H) to 5F(H)
characters are printed on
this line (18 point).

GREEN*
BLUE

1/6 inch

A 12 point hyphen is
printed 10 times on each
of 26 lines here. This
group prints in black.

1/6 inch

Yellow

Magenta Cyan Yellow Black Blue Red Green

1inch 1inch

Yellow Yellow

Fig. 3.14 Diagram of Print Test Pattern 1

This line is a printout of a
screen line in which the
column of single dots at
the left margin of each
character generator
character space is
highlighted. A row of dots
corresponding to a single
raster scan is also
highlighted in each
character space, the
raster being one lower
than in the previous
character space (total of
54 raster scans).

Printing of Co lor Bar*
* If color ink is used.

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Troubleshooting

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SERVICE MANUAL

NOTE:

The print format settings are as follows:

Font: Brougham
Type/Style: Normal (12 point/7 point);

Bold (18 point)
Line space: Auto
Left/right margins: 1.0 − 7.4 inches

Yellow

Magenta Cyan Yellow Black Blue Red Green

Fig. 3.15 Sample Print Test Pattern 1

Yellow Yellow

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7.3.2.2. Print Test Pattern 2
Purpose: To check that all characters are printed correctly.
From the Self Test menu, select "3" at the MENU screen. When printing is complete,

the display automatically return tot he Self Test menu. A sample of the printed pattern
is shown in Fig. 3.17.

Troubleshooting

*****

PRINTER CHECK

Press CANCEL to go to MENU.

Fig. 3.16 Printer Check #2 (in progress) Display

NOTES:

A paper check is performed before printing. If paper is set, the print test is executed; if

•

*****

no paper is set, the ERROR pop-up window is displayed. If you select to continue
printing, paper is automatically inserted by the ACF and to execute the print test.

Pressing the CANCEL key during printing will stop the test (paper is advanced), and

•

return the display to the Self Test menu.
If a serial number has not been input before starting the test, the pop-up window will

•

prompt for the serial number; either enter the serial number, or press RETURN to start
the test. If a serial number is entered, it will be printed on the first line of the test.

The print format settings are as follows:

•

Font: Brougham
Type/Style: Normal
Line space: Auto
Left/right margins: 0.2 inches - 8.2 inches

3-29

Troubleshooting

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SERVICE MANUAL

Pattern 4

Pattern 3

Pattern 5

Pattern 1

Pattern 2

49 6614 31

32 36

9

XXXXXXXXX (9 digits)

Pattern 6

Fig. 3.17 Sample Test Pattern 2

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SERVICE MANUAL

7.3.2.3. Dot Patterns
The following dot (print) patterns correspond to the print test #2 pattern result on the

previous page. See also Fig. 3.17 for the location of each dot pattern type.

<Pattern 2><Pattern 1>

Troubleshooting

<Pattern 4><Pattern 3>

Fig. 3.18 Dot Patterns for Print Test #2 (Patterns 1 to 4)

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Troubleshooting

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SERVICE MANUAL

<Pattern 5>

<Pattern 6>

Fig. 3.19 Dot Patterns for Print Test #2 (Patterns 5 and 6)

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SERVICE MANUAL

7.3.3. Keyboard Tests

Keyboard inspection checks that the key are making proper contact. There are three
keyboard self-tests.

(1) Select "4", "5", or "6" from the Self Test menu. If a serial number has not been input

before starting the test, the pop-up window will prompt for the serial number; either
enter the serial number, or press RETURN to start the test. The display in Fig. 3.20
below indicates that the keyboard test mode has been established.

Troubleshooting

*****

KEYBOARD TEST

Press RETURN twice to go to MENU.

Fig. 3.20 Keyboard Test #1 Display

NOTE:

The location of the keys tested in each test sequence (test 4, 5, or 6) are shown below.

•

*****

A

Fig. 3.21 Keyboard Test Key Locations

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B

Troubleshooting

(2) To run Test "4" (all keys in Fig. 3.21, "A")

a) Starting from the top left of the keyboard, press each key in turn (see

b) Then press SHIFT + Z, SHIFT + /, and CODE + SPACE. If there is no problem,

REPAIR

SERVICE MANUAL

sequence below).

the message "KB TEST OK" will be printed, and the display will return to the
SELF Test menu.

Test Keys

NOTES:

After automatic carriage return, "KB TEST OK." prints, and the display returns to the

•

SELF Test menu.
A paper check is performed before printing. If paper is set, the print test is executed; if

•

no paper is set, the ERROR pop-up window is displayed. If you select to continue
printing, paper is automatically inserted by the ACF and to execute the print test.

If the keys are pressed in the wrong sequence, a beep will sound. The test will continue

•

when the correct key is pressed.
At any time during the test, you may cancel by pressing the RETURN key twice to

•

return to the SELF Test menu.

(3) To run Test "5" (all keys in Fig. 3.21, "B")

a) Press the keys in the sequence indicated below.
b) Then press “→". If there is no problem, the message "KB TEST OK" will be

printed, and the display will return to the SELF Test menu.

Sequence

Test Keys

Sequence

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SERVICE MANUAL

(4) To run Test "6" (all keys in Fig. 3.21, "A" and "B")

a) Starting from the top left of the keyboard, press all keys ("A" & "B") in the

sequence indicated below.

b) Then press SHIFT + Z, SHIFT + /, and CODE + SPACE. If there is no problem,

the message "KB TEST OK" will be printed, and the display will return to the
SELF Test menu.

Troubleshooting

Test Keys

NOTES:

After automatic carriage return, "KB TEST OK" is printed, and the display returns to the

•

SELF Test menu.
A paper check is performed before printing. If paper is set, the print test is executed; if

•

no paper is set, the ERROR pop-up window is displayed. If you select to continue
printing, paper is automatically inserted by the ACF and to execute the print test.

If the keys are pressed in the wrong sequence, a beep sounds. The test will continue

•

when the correct key is pressed.
At any time during the test, you may cancel by pressing RETURN twice to return to the

•

SELF Test menu.

Sequence

3-35

Troubleshooting

7.3.4. FDD Tests

There are five tests of the FDD:

1. FDD Test ("7") - checks disk switch, write protect switch, and read/write errors.

2. Special FDD Test ("8") - checks disk type, write protect switch, and read/write.

3. FDD Switch Test ("9") - checks disk switch and write protect switch.

4. FDD Error Rate Check ("D") - checks for disk writing errors.

5. FDD Error Rate Check ("E") - checks for disk reading errors.

7.3.4.1. FDD Test

(1) Insert a non-write protected diskette in the disk drive, and if necessary, change the

"DISK TYPE" (2HD or 2DD) displayed on the Self Test menu to that of the test
diskette.

REPAIR

SERVICE MANUAL

(2) With paper set, select "7" from the Self Test menu. If a serial number has not been

input before starting the menu, the pop-up window will prompt for the serial number;
either enter the serial number and press RETURN, or press RETURN to start the test.
The display as shown below appears, the test results are printed, and the display
returns to the SELF Test menu.

***** *****

FDD TEST

Working . . .

.

Fig. 3.22 FDD Test (in progress) Display

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NOTES:

If a key other than the RETURN key is pressed, an error will occur.

•

A paper check is performed before printing. If paper is set, the print test is executed; if

•

no paper is set, the ERROR pop-up window is displayed. If you select to continue
printing, paper is automatically inserted by the ACF and to execute the print test.

After completing the disk drive test, the carriage automatically returns and the test

•

result is printed:

SERIAL NO.: (if it was entered)

If normal: DISK TEST OK DISK TYPE 0 (2DD)

If disk switch is defective: DISK ERROR 01
If write protect switch is defective: DISK ERROR 03
If other read/write errors occur: DISK ERROR 0F

Troubleshooting

DISK TYPE 1 (2HD)

7.3.4.2. Special FDD Test

(1) With paper set and no diskette in the disk drive, change the "DISK TYPE" (2HD or

2DD) displayed on the Self Test menu to that of test diskette.

(2) Select "8" from the Self Test menu. (If a serial number has not been input before

starting the test, the pop-up window will prompt for the serial number; either enter the
serial number and press RETURN, or press RETURN to start the test.) The display
as shown below appears:

Insert write protected disk.

*****

SPECIAL FDD TEST

Fig. 3.23 Special FDD Test Display 1

*****

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