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III

 - 6

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. According to the status, it switches to the normal
operation mode, calendar clock mode, or LCD OFF mode.

 Figure 3.2-6  ON/OFF Sequence

Switching between calendar clock mode and LCD OFF mode

Port P11 on the CPU switches Vcc that is connected to the photo-interrupter and thermal
print head. Port 13 switches LVcc that is connected to the LCD driver and its divider
resistor.
If the CPU sets P11 in high impedance to turn Vcc to 0V, then pressing the ON/OFF key
switches to the calendar clock mode.
If the CPU sets P13 to 0V to turn LVcc to 0V, then pressing the ON/OFF key switches to
the LCD OFF mode.

 Figure 3.2-7  Mode Switching Circuit

Summary of Contents for P-touch BB4

Page 1: ...SERVICE MANUAL MODEL P touch BB4 ...

Page 2: ...SERVICE MANUAL MODEL P touch BB4 ...

Page 3: ...ht 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: ...d persons to accurately and quickly provide after sale service for our P touch BB4 To perform appropriate maintenance so that the machine is always in best condition for the customer the service personnel must adequately understand and apply this manual This manual is made up of four chapters and appendix CHAPTER I SPECIFICATIONS CHAPTER II MECHANISMS CHAPTER III ELECTRONICS CHAPTER IV TROUBLESHOO...

Page 5: ...Chapter I SPECIFICATIONS ...

Page 6: ...PECIFICATIONS 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 I 5 ...

Page 7: ...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 4 keys 2 Dial 32 positions 1 1 3 Display 1 Display type Liquid crystal display LCD 2 Number of columns 8 columns x 1 row See Figure 1 1 2 3 Number of indicators 4 See Figure 1 1 2 ...

Page 8: ...ements vertically aligned Size of a heating element 0 136 mm wide by 0 106 mm high 1 1 5 Tape Cassette 1 Cassette Cartridge type 2 Tape type Direct thermal print tape 3 Tape size Width 9 12 mm Length 8 m 4 Tape cassette packed with the machine Character color Black Tape color White Tape width 12 mm or 9 mm EU Tape length 4 m 1 1 6 Tape Cutter 1 Tape cutting Manual cutting with the cutter lever 2 C...

Page 9: ...I 3 Figure 1 1 2 Key Arrangement 1 ...

Page 10: ...I 4 Figure 1 1 2 Key Arrangement 2 ...

Page 11: ... and normal humidity 4 Calendar clock default Yes If the machine remains unused for approx 1 minute with its power on then the LCD shows the calendar clock or goes off depending upon your choice 5 Low voltage indication If the voltage drops below the following level in entry mode or during printing in clock mode Then the machine will approx 5 86V approx 5 35V Display the BATTERY message approx 5 3...

Page 12: ...Chapter II MECHANISMS ...

Page 13: ...I 7 2 Removing the Chassis ASSY II 8 3 Removing the Main PCB II 11 4 Removing Battery Terminals P1 and P2 II 13 5 Removing the Rubber 4 Key Lens Dial Sheet Select Dial Select Dial Claw and Enter Key II 14 2 2 2 Reassembly Procedure II 15 1 Installing the Enter Key Select Dial Claw Select Dial Dial Sheet Lens and Rubber 4 Key II 15 2 Installing Battery Terminals P2 and P1 II 17 3 Installing the Mai...

Page 14: ...wer to the selected ones of those 64 heating elements The selected heating element s generates heat that dissolves the metal deposit layer of the thermal tape so as to reveal the substrate layer producing a dot on the tape The tape is advanced and the next heating cycle is repeated thus forming a character on the tape Character Formation While the drive motor DC motor feeds the tape by 0 106 mm fo...

Page 15: ...s pivots the roller holder ASSY around the shaft provided on the chassis so as to press the roller holder ASSY against the thermal head The platen is pressed perpendicularly against the thermal head with the tape sandwiched inbetween under a uniform load by the platen spring At the same time the platen gear becomes engaged with the drive gear of the gear train on the chassis see Figure 2 1 3 Openi...

Page 16: ...se 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 As the DC motor rotates the rotation is transmitted via the gear train to the platen gear Accordingly the sandwiched tape will be advanced Figure 2 1 3 Tape Feed Mechanism ...

Page 17: ...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 When the cassette cover is opened and no tape cassette is loaded the cutter safety mechanism works to lock the cutter lever as described in Subsection 2 1 5 Figure 2 1 4 Tape Cutter Mechanism ...

Page 18: ...cutter unit for safety as shown below Closing the cassette cover or loading a tape cassette releases the cutter safety lock mechanism If you close the cassette cover the roller holder ASSY pivots towards the thermal head so that the cutter lever stopper does not interfere with the cutter lever When a tape cassette is loaded its outer edge pushes the tab of the roller holder ASSY to pivot the rolle...

Page 19: ...uch as wires PCBs and covers 4 Be careful not to lose screws washers or other parts removed for parts replacement 5 Tighten screws to the torque values listed below Tightening Torque List Location Screw type Q ty Tightening torque Bottom cover Taptite bind B M2 6 x 6 2 0 39 N m 4 kgf cm Chassis ASSY Taptite bind B M2 6 x 4 3 0 196 N m 2 kgf cm Chassis ASSY for DC motor Screw pan M1 7 x 2 5 2 0 10 ...

Page 20: ... 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 For easier removal of the tape cassette first lift up edge B and then pull it out Figure 2 2 2 Removing the Dry Cells Tape Cassette and Cutter Unit ...

Page 21: ...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 Figure 2 2 4 Discharging Capacitor C5 and Disconnecting the Head Flat Cable ...

Page 22: ... 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 The cutter lever also comes off ...

Page 23: ...he 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 3 Pull up the roller holder ASSY together with its spring 4 Remove the two screws from the chassis ASSY and take off the DC motor ASSY Figure 2 2 6 Disassembling the Chassis ASSY ...

Page 24: ...r 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 Figure 2 2 7 Pushing out the Plus and Minus Terminal ASSYs from the Bottom Cover ...

Page 25: ... 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 Figure 2 2 8 Taking out the Main PCB with the LCD from the Body Cover ...

Page 26: ...ttery 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 ...

Page 27: ...ws 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 The select dial also comes off 4 Remove the select dial claw from the body cover 5 Unlatch the Enter key from the select dial Figure 2 2 12 Removing the Dial Sheet Select Dial Select Dial Claw and Enter key ...

Page 28: ...rientation keys 3 Set the select dial claw to the body cover After setting apply a rice sized pinch of grease Shin Etsu Silicone G501 to the top of the select dial claw as shown below 4 Place the body cover upside down 5 Set the select dial to the body cover while aligning any low section of the inner dial face with the top of the select dial claw 6 While pushing up the select dial put the dial sh...

Page 29: ...II 16 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 ...

Page 30: ...ing 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 ...

Page 31: ...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 Figure 2 2 18 Setting the Plus and Minus Terminal ASSYs ...

Page 32: ...t the chassis ASSY together with the cutter lever back into the bottom cover NOTE Route the head flat cable as illustrated below 4 Secure the chassis ASSY with three screws 5 Solder the motor lead wires to the main PCB as shown below NOTE Check the wire ID colors then solder the black and red wires to the BLACK and RED points respectively Figure 2 2 19 Installing the Chassis ASSY and Soldering the...

Page 33: ... 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 Figure 2 2 21 Securing the Bottom Cover to the Body Cover ...

Page 34: ...ller holder ASSY so that its straight end is fitted into section A on the ASSY then install them to the chassis and secure the ASSY with the retaining ring 3 As shown below turn the bent end of the roller holder spring with a flat screwdriver and fit it into an oval hole provided in the chassis Then secure the thermal head ASSY with a screw Figure 2 2 22 Assembling the Components of the Chassis AS...

Page 35: ...s 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 ...

Page 36: ...ess the Enter key The selected symbol should be established 4 Press the Print key The selected item should be printed out 5 Push the cutter lever The cutter lever should work smoothly and cut off the tape 6 Check that the printout is not faint 7 Open the cassette cover and remove the tape cassette and dry cells The above final operation check should be usually made For your reference the inspectio...

Page 37: ...m To escape from the mode and proceed to any of the INFO DIAL CUT and PRINT1 submodes rotate the select dial to any of Dial positions 1 to 4 respectively and then press the Enter key 1 Check that the LCD shows the calendar clock or its setting screen 2 Set the select dial to Blank position 3 While holding down the Print key press the Function key f The machine enters the inspection mode and shows ...

Page 38: ...termined by solder points 1 through 5 Solder points Destination The LCD shows 1 2 3 4 5 USA Canada US H H H H H France FR L H H H H Germany GE H L H H H Switzerland SZ H H L H H Belgium BE H H H L H Netherlands Holland HO H H H H L England UK H H H H H Ireland UK H H H H H South Africa UK H H H H H Italy IT L H H H H Spain SP H L H H H Denmark DE L H H H H Norway NO H L H H H Sweden SW H H L H H H...

Page 39: ...sors ON DIAL submode Dial position 2 and Enter key In any other submode setting the select dial to Dial position 2 and pressing the Enter key will jump to DIAL submode 1 When LCD check screen 3 is displayed press the Enter key The machine shows the following and enters DIAL submode 2 Make sure that the select dial is placed in Dial position 0 Blank If it is in any other position turn the select di...

Page 40: ... position 31 turn the select dial to the next position Dial position 0 then OK will appear and OK will be printed After printing is complete the screen will automatically change from OK to CUT 6 Press the cutter lever and cut the tape CUT submode Dial position 3 and Enter key In any other submode setting the select dial to Dial position 3 and pressing the Enter key will jump to CUT submode except ...

Page 41: ...al position 4 and Enter key In any other submode setting the select dial to Dial position 4 and pressing the Enter key will jump to PRINT1 submode except during checking in DIAL submode 1 When 3 is displayed press the Enter key The machine shows the following and enters PRINT1 submode 2 Press the Enter key The machine will print out the following print sample 247 dots 25 2 3 mm in length After pri...

Page 42: ...Chapter III ELECTRONICS ...

Page 43: ...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 III 6 3 2 6 Thermal Head Drive Circuit III 8 3 2 7 Oscillation Circuit III 9 3 2 8 Voltage Detection Circuit III 9 3 2 9 Power Supply Circuit III 10 3 2 10 Motor Drive Circuit III 10 3 2 11 Dial Position Detection Circuit III 12 ...

Page 44: ...nd 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 Motor The DC motor is a power source to advance tape Thermal Print Head This is a thick film thermal print head which integrates a heat generator consisting of 64 heating elements vertically aligned and driver circuitry ...

Page 45: ...m 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 6 Oscillation circuit 7 Voltage detection circuit 8 Power supply circuit 9 Motor drive circuit 10 Dial position detection circuit ...

Page 46: ...ure 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 R16 is an oscillation register that issues display timing signals V1 to V5 of the LCD driver divide Vcc by RA3 R15 to produce multi level power sources required for driving the LCD To display data the CPU writes data onto RS RW E and DB4 throu...

Page 47: ...hing element If a particular key is pressed the conductive paint of the key short circuits the paired electrodes carbon printed on the main PCB Figure 3 2 3 Detailed Diagram of Keypad Key scanning Figure 3 2 4 shows the key scan circuit and solder points The CPU scans four keys including the ON OFF key Ports P50 through P53 on the CPU issue a group of key scanning pulses Port P20 acts as an input ...

Page 48: ...der point status once in the powering in sequence to recognize the customization Solder points 1 through 5 customize the machine for the destination shipping country Solder points A through C are reserved for the future use for the thermal head ranking According to the soldered status the CPU determines the ON time length of the thermal print head 05 Belgium H H H 04 Switzerland H H L 03 France L ...

Page 49: ... mode or LCD OFF mode Figure 3 2 6 ON OFF Sequence Switching between calendar clock mode and LCD OFF mode Port P11 on the CPU switches Vcc that is connected to the photo interrupter and thermal print head Port 13 switches LVcc that is connected to the LCD driver and its divider resistor If the CPU sets P11 in high impedance to turn Vcc to 0V then pressing the ON OFF key switches to the calendar cl...

Page 50: ...or 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: ...a Figure 3 2 8 Thermal Head Drive Circuit Figure 3 2 9 shows a timing chart for thermal head drive Figure 3 2 9 Timing Chart for Thermal Head Drive Upon receipt of LATCH signal issued through P01 the thermal head drive circuit latches the serial data sent through SBO0 and supplies the power to the thermal head ASSY according to the STROBE signal issued through P03 The CPU controls the ON time leng...

Page 52: ...his circuit which is composed of divider resistors R8 and R9 steps down the power source VBT fed from dry cells and feeds the output to analog input port AN1 on the CPU According to the drive source voltage the CPU determines the optimum head driver power If the voltage drops below the following level in entry mode or during printing in clock mode Then the machine will approx 5 86V approx 5 35V Di...

Page 53: ...re 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 Through P10 the CPU produces a start stop control signal to the motor drive circuit Figure 3 2 14 shows waveforms of control signal and motor drive current Electronic governor IC U4 BA6220 controls this circuit to keep the rotation speed of the DC motor constant even if ...

Page 54: ...III 11 Figure 3 2 14 Waveforms of Control Signal and Motor Drive Current ...

Page 55: ...nning timing The CPU turns ports LED0 LED1 LED2 LED3 and LED4 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 the corresponding port The CPU scans those LEDs every 50 ms If the CPU reads the same pattern on input ports five successive times then it interprets it as the current dial position Figure 3 2 16...

Page 56: ...III 13 Figure 3 2 16 Waveforms of Dial Scanning Pulse Outputs ...

Page 57: ...Chapter IV TROUBLESHOOTING ...

Page 58: ...ING 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: ...ble is Whenever more than one trouble source is found plan the most reasonable repairing procedure after reviewing the relationship between them 2 When supplying power to this machine having problems make sure that its output voltage level is 8 to 10V under no load 3 When starting disassembly jobs first remove dry cells and discharge electrolytic capacitor C5 4 To repair an error which occurred in...

Page 60: ...IV 2 4 1 3 Troubleshooting Flows 1 Tape feeding failure ...

Page 61: ...IV 3 2 Printing failure ...

Page 62: ...IV 4 3 Powering failure Nothing appears on the LCD ...

Page 63: ...IV 5 4 Abnormal LCD indication 5 No key entry possible ...

Page 64: ...APPENDIX Circuit Diagram Main PCB ...

Page 65: ...IRCUIT DIAGRAM BB4 LA6235000 D2 short circuit pattern P22 RA2 short circuit R2 short circuit pattern DA1 short circuit pattern R10 short circuit pattern C8 normal pattern Electronic devices enclosed by a dotted line are not mounted ...

Page 66: ...Aug 2001 8V2018BE0 Printed in Japan ...

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