Brother PT-1050 User manual

SERVICE MANUAL
MODEL: PT-1000/1050/GL100

PREFACE
This publication is a service manual covering the specifications, theory of operation,
disassembly/reassembly procedure,and troubleshootingofthe BrotherPT-1000/1050.
It is intended forservice personnel and other concerned persons to accurately and
quickly provide after-sale service for our PT-1000/1050.
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 appendixes.
CHAPTER ISPECIFICATIONS
CHAPTER II THEORY OF OPERATION
CHAPTER III DISASSEMBLY & REASSEMBLY
CHAPTER IV TROUBLESHOOTING
Appendix A Main PCB Circuit Diagram
Appendix B Key PCB Circuit Diagram
© Copyright Brother 2004
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.

CONTENTS
CHAPTER I SPECIFICATIONS
1.1 Mechanical Specifications..............................................................................................I- 1
1.1.1 External Appearance................................................................................................I- 1
1.1.2 Keyboard..................................................................................................................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- 6
1.2.1 Character Generator.................................................................................................I- 6
1.2.2 Power Supply ...........................................................................................................I- 6
1.3 Key Commands for Special Functions ...........................................................................I- 7
1.3.1 Initializing..................................................................................................................I- 7
CHAPTER II THEORY OF OPERATION
2.1 Outline of Mechanisms..................................................................................................II - 1
2.1.1 Print Mechanism......................................................................................................II - 1
2.1.2 Roller Holder ASSY Setting & Retracting Mechanism..............................................II - 2
2.1.3 Tape & Ribbon Feed Mechanism.............................................................................II - 4
2.1.4 Tape Cutter Mechanism ..........................................................................................II - 6
2.1.5 Cutter Safety Lock Mechanism................................................................................II - 7
2.1.6 Cutter Jam Prevention Mechanism..........................................................................II - 8
2.2 Outline of Control Electronics........................................................................................II - 9
2.2.1 Configuration...........................................................................................................II - 9
2.2.2 Main PCB ..............................................................................................................II - 11
[ 1 ] Block Diagram .....................................................................................................II - 11
[ 2 ] Solder Points .......................................................................................................II - 12
[ 3 ] Identification of Tape Cassette Type....................................................................II - 13
CHAPTER III DISASSEMBLY & REASSEMBLY
3.1 Disassembly/Reassembly............................................................................................III - 2
[ 1 ] Removing the Cassette Cover, Tape Cassette, and Dry Cells..............................III - 2
[ 2 ] Removing the Cutter Case ASSY and Cutter Board and
Separating the Bottom Cover from the Upper Cover.............................................III - 3
[ 3 ] Removing the Frame ASSY and Cutter Lever.......................................................III - 6
[ 4 ] Removing the Terminal Press Cover and Releasing the - Terminal ASSY ...........III - 9

[ 5 ] Removing the Battery Terminals B and Releasing the + Terminal ASSY............III - 10
[ 6 ] Removing the Battery Terminals A .....................................................................III - 11
[ 7 ] Removing the Switch ASSY, Cutter Sensor ASSY and Main PCB ASSY ...........III - 12
[ 8 ] Removing the Rubber 49 Key.............................................................................III - 13
3.2 Final Check and Inspection Mode..............................................................................III - 14
CHAPTER IV TROUBLESHOOTING
4.1 Precautions................................................................................................................. IV - 1
4.2 After Repairing............................................................................................................ IV - 1
4.3 Troubleshooting Flows................................................................................................ IV - 2
[ 1 ] Tape feeding failure............................................................................................. IV - 2
[ 2 ] Printing failure...................................................................................................... IV - 4
[ 3 ] Powering failure (Nothing appears on the LCD.).................................................. IV - 6
[ 4 ] No key entry possible........................................................................................... IV - 7
[ 5 ] Tape cassette type not identified ......................................................................... IV - 8
Appendix A Main PCB Circuit Diagram
Appendix B Key PCB Circuit Diagram

I- 1
CHAPTER I SPECIFICATIONS
1.1 Mechanical Specifications
1.1.1 External Appearance
Figure 1.1-1 External Appearance
(1) Dimensions (W x D x H) 108 x 196 x 55 mm (4.3 x 7.7 x 2.2 inches)
(excl. keys, cutter lever and bottom feet)
(2) Weight
Machine proper Approx. 335 g
1.1.2 Keyboard
(1) Entry system 49-rubber keypad
(2) Key arrangement See Figure 1.1-2.
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 guidance indicators 11 (See Figure 1.1-2.)

I- 2
1.1.4 Printing Mechanism
(1) Print system Thermal transfer onto plastic and fabric tapes
(Fixed thermal print head and tape feed
mechanism)
(2) Print speed 10 mm/second
(3) Print head
Type Thermal print head
Heat generator Consists of 64 heating elements vertically
aligned in 180 dpi
Size of a heating element 0.195 mm wide by 0.141 mm high
(4) Character size Size Width High
1
2
3
4
5
28 dots
56 dots
28 dots
56 dots
112 dots
28 dots
28 dots
56 dots
56 dots
56 dots
1.1.5 Tape Cassette
(1) Cassette Cartridge type (TZ cassette)
(2) Types of tape cassettes - Laminate tape cassette
- Non-laminate tape cassette
- Fabric tape cassette
(3) Tape size
Types of tape Width
Laminate tape 6, 9, 12 mm
Non-laminate tape 6, 9, 12 mm
Fabric tape 12 mm
1.1.6 Tape Cutter
(1) Tape cutting Manual cutting with the cutter lever
(2) Cutter unit User-replaceable

I- 3
USA version
Figure 1.1-2 (1) Display and Key Arrangement

I- 4
EUROPE version
Figure 1.1-2 (2) Display and Key Arrangement

I- 5
UK version (GL-100)
Figure 1.1-2 (3) Display and Key Arrangement

I- 6
1.2 Electronics Specifications
1.2.1 Character Generator
(1) Internal characters 240
(2) Internal fonts HELSINKI and OKLAHOMA
(3) Text buffer Max. 55 characters
(4) File memory Max. 300 characters
(5) Memory backup
No dedicated backup battery is provided. However, the memory is backed up for 5
minutes even after:
1) you remove the dry cells (e.g., at the replacement time of dry cells) without
connection of the optional AC adapter.
2) you unplug the optional AC adapter (being plugged in the AC jack of the
machine) from the wall socket without dry cells loaded.
If the machine is loaded with dry cells when you unplug the AC adapter (being
plugged in the AC jack of the machine) from the wall socket, the memory will be
backed up by those dry cells.
1.2.2 Power Supply
(1) Power supply Driven by 6 dry cells
Optional AC adapter available
- AD-30 (U.S.A.)
- Model G1 (Europe)
(2) Battery type Alkaline dry cells (LR03) that come with the
machine.
(3) Service life of batteries Will last through one 12-mm wide tape
cassette, and then some (at room temperature
and normal humidity).
(4) Automatic powering-off Yes (If the machine remains unused for approx.
5 minutes, it automatically turns itself off.)
(5) Low battery detection and indication
When the machine is driven by dry cells:
- If the voltage level exceeds 10.81 V or drops below 6.84 V when the machine is
on standby, the machine automatically turns itself off.
- If the voltage level drops below 5.12 V, 4.85 V, or 4.31 V during printing, the
machine displays the "BATTERY" message to warn the user of the low battery
after completion of printing, stops printing, or shuts down the power immediately,
respectively.
When the machine is driven via the AC adapter:
If the input voltage is out of the specified level range, the machine immediately
shuts down the power.

I- 7
1.3 Key Commands for Special Functions
1.3.1 Initializing
When the machine power is off, pressing the key with both the Function and Rkeys
held down initializes the machine. When releasing those keys, be sure to first release the
key and then release the Function and Rkeys.

II - 1
CHAPTER II THEORY OF OPERATION
2.1 Outline of Mechanisms
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 in 180 dpi as shown in
Figure 2.1-1. Each heating element is 0.195 mm wide by 0.141 mm high.
Figure 2.1-1 Heat Generator of Thermal Head
nPrinting Process
When the cylindrical rubber platen is pressed against the thermal print head with the tape
and ink ribbon sandwiched inbetween, the CPU applies current to the selected ones out of
the 64 heating elements.
If the selected heating element(s) generates heat, the ink on the sandwiched ribbon will
be melted and transferred to the tape, producing a dot(s) on the tape. The ink ribbon and
the tape are advanced and then the next heating cycle is repeated, thus forming a graphic
pattern on the tape.
nGraphic Pattern Formation
While the drive motor (DC motor) feeds the tape and ink ribbon by 0.141 mm for 14.1 ms,
the thermal head generates heat once. The feed amount of 0.141 mm is smaller than the
width (0.195 mm) of the heating elements so that the heat generated at one heating cycle
will overlap with the next heating cycle. This forms a graphic pattern having no gap
between adjacent printed dots.

II - 2
2.1.2 Roller Holder ASSY Setting & Retracting Mechanism
This mechanism consists of the roller holder ASSY and the holder cam (provided on the
cassette cover ASSY).
The cassette cover has a holder cam on the inside. Closing the cassette cover causes its
holder cam to press section A of the roller holder ASSY as shown below. This pivots the
roller holder ASSY around the shaft provided on the frame ASSY so as to press the roller
holder ASSY against the thermal head side.
Figure 2.1-2 Holder Cam on the Cassette Cover
Figure 2.1-3 Holder Cam and Roller Holder ASSY

II - 3
The roller holder ASSY supports the platen roller and tape feed sub roller so that they can
move perpendicularly to the thermal head and tape feed roller built in a tape cassette,
respectively, as well as rotating freely.
Closing the cassette cover presses the platen roller perpendicularly against the thermal
head with the tape and ink ribbon sandwiched inbetween under a uniform load by the
upper and lower roller holder springs. At the same time, the platen gear becomes
engaged with the platen idle gear.
The tape feed sub roller is pressed perpendicularly against the tape feed roller built in the
tape cassette with the tape (and adhesive base paper when using laminate tape
cassettes) sandwiched inbetween under a uniform load by the upper and lower roller
holder springs. At the same time, the sub roller gear becomes engaged with the tape idle
gear.
Opening the cassette cover pulls out its holder cam so that the roller holder release spring
retracts the roller holder ASSY from the thermal head, providing you with enough space to
replace the tape cassette.
Figure 2.1-4 Roller Holder ASSY Setting & Retracting Mechanism

II - 4
2.1.3 Tape & Ribbon Feed Mechanism
This mechanism consists of a drive motor (DC motor), gear train, and roller holder ASSY.
nTape Feeding
As the drive motor rotates, the rotation is transmitted via the gear train to the platen idle
gear (which rotates the platen gear) and tape idle gear (which rotate the tape feed roller
and its sub roller at the same rotation speed).
Accordingly, the sandwiched tape and ink ribbon will be advanced at the constant speed.
(When a laminate tape cassette is mounted, the sandwiched laminate tape, ink ribbon and
adhesive base tape will be advanced together).
Figure 2.1-5 Tape Feeding Mechanism

II - 5
nAdhesive Base Tape Feeding (only for laminate tape cassettes)
A laminate tape cassette contains both a transparent laminate tape roll and a separate
adhesive base tape roll.
When a transparent laminate tape and adhesive base tape pass through the contact point
(between the tape feed roller and tape feed sub roller), they are then bonded together into
a single, printed tape. The ink printed on the laminate tape is, therefore, sealed up with
the adhesive base tape.
nInk Ribbon Feeding
As the drive motor rotates, the ribbon drive cam located at the middle of the gear train
rotates counterclockwise. When fitted on the ribbon drive cam, the ribbon take-up roll in
the tape cassette also rotates to take up the ink ribbon.
To apply proper tension to the ink ribbon between the platen and the ribbon drive cam, the
feed amount of the ribbon drive cam is slightly greater than that of the tape feed gear. The
difference between the feed speeds at the platen roller and at the ribbon drive cam is
absorbed by the clutch spring which is integrated in the ribbon drive cam and allows the
cam to slip.
This way, the ink ribbon is kept tense, which enables the ribbon to clearly separate from
the tape at the stabilized angle after printing.
Figure 2.1-6 Ribbon Feeding Mechanism

II - 6
2.1.4 Tape Cutter Mechanism
The tape cutter ASSY consists of a cutter case ASSY and cutter board.
Pressing the cutter lever pushes out the cutter blade against the cutter board, cutting the
printed tape coming through the cutter case ASSY and cutter board.
Figure 2.1-7 Tape Cutter Mechanism

II - 7
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 release spring (as described in
Section 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 blade from getting driven for safety,
as shown below.
Closing the cassette cover 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.
Figure 2.1-8 Cutter Safety Lock Mechanism
Figure 2.1-9 Releasing the Cutter Safety Lock Mechanism

II - 8
2.1.6 Cutter Jam Prevention Mechanism
When the machine is printing or feeding tape, pressing the cutter lever turns on the cutter
sensor switch via the cutter sensor arm and immediately stops the DC motor. This
prevents the cutter blade from interrupting the tape being fed and causing a tape jam.
Figure 2.1-10 Cutter Jam Prevention Mechanism

II - 9
2.2 Outline of Control Electronics
2.2.1 Configuration
Figure 2.2-1 shows a block diagram of the control electronics of this machine. The control
electronics consists of two PCBs (main PCB and key PCB), an LCD, motor, thermal print
head, tape cassette sensor (switch ASSY) and cutter sensor.
nMain PCB
This PCB manages all the components including an LCD, motor and thermal print head.
For electronic devices on the main PCB, refer to Section 2.2.2.
nKey PCB
This PCB holds an AC jack.
nLCD
The LCD is 8 characters wide by one row high and it has 11 guidance indicators.
nMotor
The DC motor is a power source to advance tape and ink ribbon.
nThermal print head
This is a thick-film thermal print head which integrates a heat generator (consisting of 64
heating elements vertically aligned in 180 dpi) and driver circuitry.
nTape cassette sensor (switch ASSY)
According to the states of the three sensor switches on this sensor, the CPU can identify
the tape width and type of the tape cassette loaded.
nCutter sensor
Pressing the cutter lever turns on this sensor, signaling that the cutter is driven. If this
sensor is turned on during printing or tape feeding, the CPU immediately stops the motor
to prevent tape jamming.