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Brother P-touch BB4 Service Manual

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SERVICE MANUAL
MODEL: P-touch BB4

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Summary of Contents for Brother P-touch BB4

  • Page 1 SERVICE MANUAL MODEL: P-touch BB4...
  • Page 2 SERVICE MANUAL MODEL: P-touch BB4...
  • Page 3 © Copyright Brother 2001 All rights reserved. No part of this publication may be reproduced in any form or by any means without permission in writing from the publisher. Specifications are subject to change without notice.
  • Page 4 PREFACE This publication is a service manual covering the specifications, theory of operation, disassembly/reassembly procedure, and troubleshooting of the Brother P-touch BB4. It is intended for service personnel and other concerned persons to accurately and quickly provide after-sale service for our P-touch BB4.
  • Page 5 Chapter I. SPECIFICATIONS...

  • Page 6: Table Of Contents

    CONTENTS CHAPTER I. SPECIFICATIONS 1.1 MECHANICAL SPECIFICATIONS..................I-1 1.1.1 External Appearance....................I-1 1.1.2 Entry system ......................I-1 1.1.3 Display ........................I-1 1.1.4 Printing Mechanism....................I-2 1.1.5 Tape Cassette......................I-2 1.1.6 Tape Cutter ......................I-2 1.2 ELECTRONICS SPECIFICATIONS..................I-5 1.2.1 Character Generator ....................I-5 1.2.2 Power Supply ......................

  • Page 7: Mechanical Specifications

    1.1 MECHANICAL SPECIFICATIONS 1.1.1 External Appearance Figure 1.1-1 External Appearance (1) Dimensions (W x D x H) 105 mm x 154 mm x 52 mm (2) Weight Machine proper Approx. 250 g In package Approx. 500 g (incl. a tape cassette, excl. dry cells) 1.1.2 Entry system (1) Rubber keypad...

  • Page 8: Printing Mechanism

    1.1.4 Printing Mechanism (1) Print system Direct thermal printing (Fixed print head and tape feeding mechanism) (2) Print speed 7.5 mm/second (Typical) (3) Print head Type Thermal print head Heat generator Consists of 64 heating elements vertically aligned Size of a heating element 0.136 mm wide by 0.106 mm high 1.1.5 Tape Cassette...
  • Page 9 Figure 1.1-2 Key Arrangement (1) I - 3...
  • Page 10 Figure 1.1-2 Key Arrangement (2) I - 4...

  • Page 11: Electronics Specifications

    1.2 ELECTRONICS SPECIFICATIONS 1.2.1 Character Generator (1) No. of printable symbols (2) Internal fonts HELSINKI (3) Phrase memory capacity None 1.2.2 Power Supply (1) Power supply Driven by 6 dry cells (2) Battery type Alkaline dry cells (AM3/LR6) (3) Service life of batteries Will last through one tape cassette, and then some (at room temperature and normal humidity).
  • Page 12 Chapter II. MECHANISMS...
  • Page 13 CONTENTS CHAPTER II. MECHANISMS 2.1 THEORY OF OPERATION ....................II-1 2.1.1 Print Mechanism ..................... II-1 2.1.2 Platen Setting & Retracting Mechanism ..............II-2 2.1.3 Tape Feed Mechanism.................... II-3 2.1.4 Tape Cutter Mechanism ..................II-4 2.1.5 Cutter Safety Lock Mechanism................II-5 2.2 DISASSEMBLY &...

  • Page 14: Theory Of Operation

    2.1 THEORY OF OPERATION 2.1.1 Print Mechanism Structure of Thermal Head This machine uses direct thermal printing. The thermal print head has a heat generator consisting of 64 heating elements which are vertically aligned as shown in Figure 2.1-1. Each heating element is 0.136 mm wide by 0.106 mm high. 0.106 mm 6.784 mm 0.136 mm...

  • Page 15: Platen Setting & Retracting Mechanism

    2.1.2 Platen Setting & Retracting Mechanism This mechanism consists of the roller holder ASSY and the roller holder setting lever (wedged lever) provided on the inside of the cassette cover. The roller holder ASSY supports the platen so that the platen can move perpendicularly to the thermal head and rotate freely.

  • Page 16: Tape Feed Mechanism

    2.1.3 Tape Feed Mechanism This mechanism consists of a DC motor, gear train and roller holder ASSY. When you load a tape cassette and close the cassette cover, the platen and the thermal head sandwich the tape inbetween and the platen gear becomes engaged with the gear train, as described in Subsection 2.1.2.

  • Page 17: Tape Cutter Mechanism

    2.1.4 Tape Cutter Mechanism The cutter mechanism consists of a cutter lever and a cutter unit in which a blade is retracted by a spring. Pressing the cutter lever pushes out the blade from the cutter unit. The blade presses the printed tape against the cutter board of the tape cassette, cutting the tape coming through the cutter unit and the cutter board.

  • Page 18: Cutter Safety Lock Mechanism

    2.1.5 Cutter Safety Lock Mechanism When the cassette cover is opened and no tape cassette is loaded, the roller holder ASSY is retracted from the thermal head with the roller holder spring (as described in Subsection 2.1.2). In this retracted position, the cutter lever stopper of the roller holder ASSY blocks the end of the cutter lever, preventing the cutter lever from pushing the cutter blade out of the cutter unit for safety, as shown below.

  • Page 19: Disassembly & Reassembly

    2.2 DISASSEMBLY & REASSEMBLY Safety Precautions (1) You should carry out disassembly & reassembly jobs on an anti-static sheet grounded correctly. Otherwise, the LSI and other electronic devices will be damaged due to the electricity charged in your body. (2) When transporting PCBs, be sure to wrap them in conductive sheets such as aluminum foil.

  • Page 20: Disassembly Procedure

    2.2.1 Disassembly Procedure [ 1 ] Removing the Cassette Cover, Dry Cells, Tape Cassette, and Cutter Unit (1) Turn the machine upside down. (2) Press section "A" of the cassette cover to release the latch, and then remove the cassette cover. Figure 2.2-1 Removing the Cassette Cover (3) Remove six dry cells, tape cassette, and cutter unit.

  • Page 21: 2 ] Removing The Chassis Assy

    [ 2 ] Removing the Chassis ASSY (1) Remove the two screws from the bottom cover. Figure 2.2-3 Unscrewing the Bottom Cover (2) Slightly open the bottom cover, discharge capacitor C5 with a screwdriver or the like, and then disconnect the head flat cable from the main PCB, as illustrated below. NOTE: Take care not to bend the head flat cable.
  • Page 22 (3) Unsolder the motor lead wires from the main PCB. NOTE: Do not unsolder the wires of the plus and minus terminal ASSYs. (4) Remove the three screws from the chassis ASSY. Figure 2.2-5 Unsoldering the Motor Lead Wires and Removing the Chassis ASSY (5) Lift the chassis ASSY up and out of the bottom cover.
  • Page 23 Disassembling the Chassis ASSY When handling the thermal head ASSY, do not touch the thermal head by hand. It may be easily damaged due to the electricity charged in your body. (1) Remove the screw from the thermal head ASSY and take off the ASSY. (2) Remove the retaining ring from the shaft of the chassis ASSY.

  • Page 24: 3 ] Removing The Main Pcb

    [ 3 ] Removing the Main PCB (1) From the battery holder side of the bottom cover, unlatch the locking pawl of each of the plus and minus terminal ASSYs with the tip of a flat screwdriver, and then push them out of the bottom cover.
  • Page 25 (2) Remove two screws from the main PCB. (3) While pressing the guides of the LCD flat cable outwards, slightly slide the LCD flat cable to the right and left and release it. NOTE: Take care not to bend the LCD flat cable. (4) Unlatch the LCD and take it out gently.

  • Page 26: 4 ] Removing Battery Terminals P1 And P2

    [ 4 ] Removing Battery Terminals P1 and P2 (1) As shown below, remove battery terminals P1 from the bottom cover with the flat screwdriver. Figure 2.2-9 Taking out Battery Terminals P1 from the Bottom Cover (2) As shown below, remove battery terminals P2 with the flat screwdriver. Figure 2.2-10 Taking out Battery Terminals P2 from the Bottom Cover II - 13...

  • Page 27: 5 ] Removing The Rubber 4 Key, Lens, Dial Sheet, Select Dial, Select Dial Claw, And Enter Key

    [ 5 ] Removing the Rubber 4 Key, Lens, Dial Sheet, Select Dial, Select Dial Claw, and Enter Key (1) Remove the rubber 4 key. (2) Remove the two screws from the lens and take it out. Figure 2.2-11 Removing the Rubber 4 Key and Lens (3) Remove the three screws and take out the dial sheet.

  • Page 28: Reassembly Procedure

    2.2.2 Reassembly Procedure [ 1 ] Installing the Enter Key, Select Dial Claw, Select Dial, Dial Sheet, Lens, and Rubber 4 Key (1) Apply a rice-sized pinch of grease (Shin-Etsu Silicone G501) to each of the two lubrication points on the end of the body cover which the inside of the select dial will come into contact with, as shown below.
  • Page 29 (8) Secure the lens with two screws. (9) Set the rubber 4 key into place. Figure 2.2-14 Reinstalling the Rubber 4 key and Lens II - 16...

  • Page 30: 2 ] Installing Battery Terminals P2 And P1

    [ 2 ] Installing Battery Terminals P2 and P1 (1) Snap battery terminals P2 into the bottom cover. Figure 2.2-15 Setting Battery Terminals P2 (2) Snap battery terminals P1 into the bottom cover. Figure 2.2-16 Setting Battery Terminals P1 II - 17...

  • Page 31: 3 ] Installing The Main Pcb

    [ 3 ] Installing the Main PCB (1) Secure the main PCB to the body cover with two screws. (2) Route the LCD flat cable through the cable guides while pressing them outwards. (3) Set the LCD into place while pressing the arms outwards. Figure 2.2-17 Reinstalling the Main PCB (4) Snap each of the plus and minus terminal ASSYs into the bottom cover.

  • Page 32: 4 ] Installing The Chassis Assy

    [ 4 ] Installing the Chassis ASSY (1) If the chassis ASSY has been disassembled, assemble the components, referring to page II-21. (2) As shown in Figure 2.2-22, fit the cutter lever onto the shaft on the chassis ASSY. (3) Put the chassis ASSY together with the cutter lever back into the bottom cover. NOTE: Route the head flat cable as illustrated below.
  • Page 33 (6) While holding the bottom cover in an angle shown below, connect the head flat cable to the main PCB. (7) Close the bottom cover. Figure 2.2-20 Connecting the Head Flat Cable (8) Secure the bottom cover to the body cover with two screws, taking care not to pinch the wires between those covers.
  • Page 34 Assembling the Components of the Chassis ASSY (1) Secure the DC motor ASSY to the chassis with two screws so that the motor lead wires face as shown below. (2) Set the roller holder spring onto the roller holder ASSY so that its straight end is fitted into section "A"...

  • Page 35: 5 ] Setting The Cutter Unit, Tape Cassette, Dry Cells, And Cassette Cover

    [ 5 ] Setting the Cutter Unit, Tape Cassette, Dry Cells, and Cassette Cover (1) Set the cutter unit into place. (2) Set a tape cassette. (3) Load six dry cells. (4) First fit the hook of the cassette cover and then snap the cover into place. Figure 2.2-23 Setting the Cutter Unit, Tape Cassette, Dry Cells, and Cassette Cover II - 22...

  • Page 36: 6 ] Final Operation Check

    [ 6 ] Final Operation Check After reassembling, do the following: (1) Load dry cells. The display should blink. (2) Press the Power key twice. The calendar clock should appear. (3) Turn the select dial to the desired position and press the Enter key. The selected symbol should be established.

  • Page 37: 7 ] Inspection Mode

    [ 7 ] Inspection Mode Enter the inspection mode according to the procedure given below and make the final check. In the inspection mode, you use four submodes--INFO, DIAL, CUT, and PRINT1 submodes. TIP: The inspection mode supports a total of nine submodes for factory checking. That is, there are five more submodes which are not described in this manual.
  • Page 38 INFO submode (Dial position 1 and Enter key*) (*In any other submode, setting the select dial to Dial position 1 and pressing the Enter key will jump to INFO submode, except during checking in DIAL submode.) The moment the machine enters the inspection mode, it shows "INFO," indicating that the machine is placed in INFO submode.
  • Page 39 2) Press the Enter key. LCD check screen 1 will appear as shown below. 3) Press the Enter key. LCD check screen 2 will appear as shown below. (All guidance indicators & cursors: ON) 4) Press the Enter key. LCD check screen 3 will appear as shown below. (All guidance indicators &...
  • Page 40 4) Counterclockwise turn the select dial slowly and check that the correct dial position number will be displayed. NOTE: Do not turn the select dial quickly or clockwise. Doing so cannot check the dial operation correctly. If the select dial is set to any wrong position, "X" will display as shown below.
  • Page 41 After feeding tape, the machine will display the following: 2) Press the Enter key. While displaying the following, the machine will feed tape. After feeding tape, the machine will display the following: 3) Press the Enter key. While displaying the following, the machine will feed tape. After feeding tape, the machine will display the following: PRINT1 submode (Dial position 4 and Enter key*) (*In any other submode, setting the select dial to Dial position 4 and pressing the Enter key...
  • Page 42 Chapter III. ELECTRONICS...
  • Page 43 CONTENTS CHAPTER III. ELECTRONICS 3.1 OUTLINE OF CONTROL ELECTRONICS ................III-1 3.1.1 Configuration......................III-1 3.2 MAIN PCB .......................... III-2 3.2.1 Block Diagram......................III-2 3.2.2 CPU ........................III-3 3.2.3 LCD Driver ......................III-3 3.2.4 Key Contacts and Solder Points................III-4 3.2.5 ON/OFF Key and Its Circuit..................

  • Page 44: Outline Of Control Electronics

    3.1 OUTLINE OF CONTROL ELECTRONICS 3.1.1 Configuration Figure 3.1-1 shows a block diagram of the control electronics of this machine. The control electronics consists of a main PCB, DC motor, and thermal print head ASSY. Figure 3.1-1 Configuration of the Electronic Part Main PCB This manages all the components including an LCD, DC motor, keypad, and thermal print head ASSY.

  • Page 45: Main Pcb

    3.2 MAIN PCB 3.2.1 Block Diagram Figure 3.2-1 shows a block diagram of the main PCB. Figure 3.2-1 Block Diagram of Main PCB The main PCB consists of the following: (1) CPU (including a ROM and RAM) (2) LCD driver (3) Key contacts and solder points (4) ON/OFF key and its circuit (5) Thermal head drive circuit...

  • Page 46: Cpu

    3.2.2 CPU The CPU (U1: MN101C30A) is an 8-bit microprocessor produced by CMOS silicon gate process. which integrates a 32-kilobyte ROM and a 1.5-kilobyte RAM. It controls and manages the entire system. 3.2.3 LCD Driver Figure 3.2-2 shows a LCD driver. Figure 3.2-2 LCD Driver The LCD driver (U3: SPLC780A) is an LSI which has common drive pins and column drive pins to drive the LCD.

  • Page 47: Key Contacts And Solder Points

    3.2.4 Key Contacts and Solder Points On the main PCB are four carbon-printed contact patterns. Each contact pattern has a pair of electrodes. Keypad The rubber keypad is made of high-impedance silicon rubber. As shown in Figure 3.2-3, each key on the rubber keypad consists of a key top, rubber spring, and conductive paint which functions as a switching element.
  • Page 48 Scanning timing The CPU turns ports P50, P51, P52, and P53 Low in this order. When not Low, those ports are High or in high impedance. When a particular port out of them is Low, the CPU reads the status of port P20. The CPU scans those key contacts every 10 ms.

  • Page 49: On/Off Key And Its Circuit

    3.2.5 ON/OFF Key and Its Circuit ON/OFF key As shown in Figure 3.2-6, pressing the ON/OFF key turns the CPU's IRQ0 Low so as to interrupt the CPU. Releasing the ON/OFF key turns the IRQ0 High. Upon detection of the High IRQ0, the CPU checks the P11 and P13 status.
  • Page 50 Automatic powering-off If you make no key entry for approx. 1 minute, the CPU automatically enters calendar clock mode or LCD OFF mode when Vcc is 0V (P11 is in high impedance) or LVcc is 0V (P13 at 0V), respectively. Pressing the ON/OFF key in calendar clock mode or LCD OFF mode switches to normal operation mode.

  • Page 51: Thermal Head Drive Circuit

    3.2.6 Thermal Head Drive Circuit Figure 3.2-8 shows the thermal head drive circuit. The thermal head has an integrated heat generator (consisting of 64 heating elements vertically aligned in 180 dpi) and a built-in driver IC. Synchronizing with the clock on SBT0, the CPU outputs print data on SBO0 in serial form. One issue contains a total of 64 dots, 8 sets of 8-bit data.

  • Page 52: Oscillation Circuit

    3.2.7 Oscillation Circuit Figure 3.2-10 shows the oscillation circuit. This circuit contains two oscillators to generate 8.00 MHz frequency which acts as a CPU basic clock and 32.768 kHz frequency for calendar clock. Figure 3.2-10 Oscillation Circuit 3.2.8 Voltage Detection Circuit Figure 3.2-11 shows the voltage detection circuit.

  • Page 53: Power Supply Circuit

    3.2.9 Power Supply Circuit Figure 3.2-12 shows a power supply circuit. The 3-terminal regulator (RH5RL33A) stabilizes the battery output, producing the 3.3V power source. Capacitor C13 is for the logic circuit and C5 is for driving the thermal head and DC motor. Figure 3.2-12 Power Supply Circuit 3.2.10 Motor Drive Circuit Figure 3.2-13 shows the drive circuit of the DC motor which feeds tape.
  • Page 54 Figure 3.2-14 Waveforms of Control Signal and Motor Drive Current III - 11...

  • Page 55: Dial Position Detection Circuit

    3.2.11 Dial Position Detection Circuit Dial LED scanning Figure 3.2-15 shows the LED scan circuit that detects the dial position. The CPU scans five LEDs. Ports LED0 through LED4 on the CPU issue a group of LED scanning pulses. Port AN2 through AN6 act as input ports that receive LED status. Scanning timing The CPU turns ports LED0, LED1, LED2, LED3, and LED4 Low in this order.
  • Page 56 Figure 3.2-16 Waveforms of Dial Scanning Pulse Outputs III - 13...
  • Page 57 Chapter IV. TROUBLESHOOTING...
  • Page 58 CONTENTS CHAPTER IV. TROUBLESHOOTING 4.1 TROUBLESHOOTING......................IV-1 4.1.1 Precautions ......................IV-1 4.1.2 After Repairing .......................IV-1 4.1.3 Troubleshooting Flows ................... IV-2 [ 1 ] Tape feeding failure ....................IV-2 [ 2 ] Printing failure ......................IV-3 [ 3 ] Powering failure (Nothing appears on the LCD.) ............ IV-4 [ 4 ] Abnormal LCD indication..................IV-5 [ 5 ] No key entry possible.....................IV-5...

  • Page 59: Troubleshooting

    4.1 TROUBLESHOOTING This section gives the service personnel some of the troubleshooting procedures to be followed if an error or malfunction occurs with this machine. It is impossible to anticipate all of the possible troubles which may occur in future and determine the troubleshooting procedures, so this chapter covers some sample troubles.

  • Page 60: Troubleshooting Flows

    4.1.3 Troubleshooting Flows [ 1 ] Tape feeding failure IV - 2...

  • Page 61: 2 ] Printing Failure

    [ 2 ] Printing failure IV - 3...

  • Page 62: 3 ] Powering Failure (Nothing Appears On The Lcd

    [ 3 ] Powering failure (Nothing appears on the LCD.) IV - 4...

  • Page 63: 4 ] Abnormal Lcd Indication

    [ 4 ] Abnormal LCD indication [ 5 ] No key entry possible IV - 5...
  • Page 64 APPENDIX Circuit Diagram Main PCB...
  • Page 65 Appendix. Main PCB D2 short-circuit pattern P22, RA2 short-circuit R2 short-circuit pattern DA1 short-circuit pattern R10 short-circuit pattern C8 normal pattern CIRCUIT DIAGRAM BB4 NAME LA6235000 CODE Electronic devices enclosed by a dotted line are not mounted.
  • Page 66 Aug., 2001 8V2018BE0 Printed in Japan...

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