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Brother T-8422C Instruction Manual

Instruction manual - english
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T-8421C, 8422C
T-8452C, 8722C
T-8752C
Please read this manual before using the machine.
Please keep this manual within easy reach for quick reference.
TWIN NEEDLE DIRECT DRIVE LOCK STITCHER
INSTRUCTION MANUAL

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  Summary of Contents for Brother T-8422C

  • Page 1 INSTRUCTION MANUAL T-8421C, 8422C T-8452C, 8722C T-8752C Please read this manual before using the machine. Please keep this manual within easy reach for quick reference. TWIN NEEDLE DIRECT DRIVE LOCK STITCHER...
  • Page 2 Thank you very much for buying a BROTHER sewing machine. Before using your new machine, please read the safety instructions below and the explanations given in the instruction manual. With industrial sewing machines, it is normal to carry out work while positioned directly in front of moving parts such as the needle and thread take-up, and consequently there is always a danger of injury that can be caused by these parts.
  • Page 3: Safety Instructions

    SAFETY INSTRUCTIONS [1] Safety indications and their meanings This instruction manual and the indications and symbols that are used on the machine itself are provided in order to ensure safe operation of this machine and to prevent accidents and injury to yourself or other people. Indications DANGER The instructions which follow this term indicate situations where failure to follow the...
  • Page 4 [2] Notes on safety DANGER Wait at least 5 minutes after turning off the power switch and disconnecting the power cord from the wall outlet before opening the cover of the control box. Touching areas where high voltages are present can result in severe injury.
  • Page 5: Maintenance And Inspection

    CAUTION Sewing This sewing machine should only be used by Attach all safety devices before using the sewing operators who have received the necessary training machine. If the machine is used without these in safe use beforehand. devices attached, injury may result. Do not touch any of the moving parts or press any The sewing machine should not be used for any objects against the machine while sewing, as this...
  • Page 6 [3] Warning labels The following warning labels appear on the sewing machine. Please follow the instructions on the labels at all times when using the machine. If the labels have been removed or are difficult to read, please contact your nearest Brother dealer. Touching areas where high voltages are present can Be careful not to get your hands result in severe injury.
  • Page 7 Oil pan Control box Transformer box (100V/400V system only) 2166B 2506B Oil tank T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 8: Table Of Contents

    CONTENTS 1. MACHINE SPECIFICATIONS ....6. USING THE G50 OPERATION PANEL (ADVANCED OPERATIONS)....2. NAMES OF MAJOR PARTS ....6-1. Names and functions ........34 3. INSTALLATION ........6-2. Adjusting the needle up stop position .....35 3-1. Table processing diagram ......5 6-3.
  • Page 9 11. CLEANING ......... 11-1. Daily cleaning procedures ......55 11-2. Lubricating via the oil cover (every 6 months)........... 56 11-3. Applying grease (Semi dry specifications) [When “GrUP” appears ... When using the G50 operation panel]..57 11-4. Applying grease (Semi dry specifications) [When “GrUP”...
  • Page 10: Machine Specifications

    1. MACHINE SPECIFICATIONS 1. MACHINE SPECIFICATIONS 2167B A B C D E F Rotary hook Standard hook Large hook Stitch function Fixed needle bar Split needle bar Thread trimmer ○ Quick reverse ○ ○ Thread wiper ○ Lubrication type Minimum lubrication Semi dry Heavy-weight Light-weight and...
  • Page 11 Knee lifter 13 mm Feed dog height 1 mm Needle (DP×5) #9–#14 #11–#16 Motor AC servo motor (4-pole, 550W) Control circuit Microprocessor T-8422C -403 -433 -405, -407 Max. sewing speed 4,000 sti/min 3,000 sti/min Start backtacking continuous 250–1,800 sti/min backtacking speed...
  • Page 12: Names Of Major Parts

    2. NAMES OF MAJOR PARTS 2. NAMES OF MAJOR PARTS G50 operation panel (advanced function LCD) G10 operation panel (basic function LED) 2168B Bobbin winder Thread wiper (T-8422C, 8452C, 8722C, 8752C) Lifting lever Quick reverse (Actuator switch) Presser foot Control box Knee lifter assembly...
  • Page 13: Installation

    3. INSTALLATION 3. INSTALLATION CAUTION Machine installation should only be carried out by a Secure the table so that it will not move when tilting qualified technician. back the machine head. If the table moves, it may crush your feet or cause other injuries. Contact your Brother dealer or a qualified electrician for any electrical work that may need to be done.
  • Page 14: Table Processing Diagram

    3. INSTALLATION 3-1. Table processing diagram The top of the table should be 40 mm in thickness and should be strong enough to hold the weight and with-stand the vibration of the sewing machine. Drill holes as indicated in the illustration below. Cotton stand hole Cord hole Head rest hole...
  • Page 15: Oil Pan

    3. INSTALLATION 3. Oil pan (1) Head cushions (left) [2 pcs] (2) Head cushions (right) [2 pcs] (3) Oil pan (4) Oiler 2874M 4. Rubber cushions (1) Rubber cushions [2 pcs] (2) Nails [4 pcs] 5. Knee lifter complying bar (3) Knee lifter complying bar 2875M T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 16: Machine Head

    3. INSTALLATION 6. Machine head (1) Hinges [2 pcs] (2) Machine head (3) Head rest NOTE: Tap the head rest (3) securely into the table hole. If the head rest (3) is not pushed in as far as it will go, the machine head will not be sufficiently stable when it is tilted back.
  • Page 17 3. INSTALLATION 9. Knee lifter plate (1) Knee lifter plate (2) Bolt * Loosen the bolt (3) and the bolt (4), and move the knee lifter plate (1) to a position where it is easy to use. 2173B <Knee lifter adjustment> 1.
  • Page 18: Lubrication

    3. INSTALLATION 3-3. Lubrication CAUTION Do not connect the power cord until lubrication has been completed, otherwise the machine may operate if the treadle is depressed by mistake, which could result in injury. Be sure to wear protective goggles and gloves when handling the lubricating oil and grease, so that they do not get into your eyes or onto your skin, otherwise inflammation can result.
  • Page 19 3. INSTALLATION ■ Lubrication Apply 1 - 2 drops of oil to the places indicated by the arrows. <Minimum lubrication type only> * Do not apply oil for semi dry types. <T-8452C, 8752C> 2200B <Semi dry type and minimum lubrication type> Rotary hook race (left and right) 2174B...
  • Page 20: Connecting The Cords

    3. INSTALLATION 3-4. Connecting the cords DANGER Wait at least 5 minutes after turning off the power switch and disconnecting the power cord from the wall outlet before opening the face plate of the control box. Touching areas where high voltages are present can result in severe injury.
  • Page 21 3. INSTALLATION (1) 6-pin head detector unit connector (2) 12-pin operation panel connector (3) 10-pin resolver connector (4) 14-pin machine connector (5) 4-pin motor connector Raise the tab (6). Lower the tab (6). Push in securely until the tabs (6) engage. 4139M Binding the cords 4140M...
  • Page 22: Other Cords

    3. INSTALLATION 3. Ground wire (1) Ground wire (2) Washer (3) Spring washer (4) Screw Oil pan Ground symbol Ground symbol 2176B 4. Other cords 4143M Connect cords that match the voltage specifications. < Europe specifications > (1) Filter box (2) Screws [4 pcs.] (3) Staples [7 pcs.] (4) Power cord...
  • Page 23 3. INSTALLATION <200V system> (1) Power switch (2) Screws [2 pcs] Operator 4145M (3) 3-pin power supply connector 2177B (4) Power cord (5) Staples [5 pcs.] 1. Attach an appropriate plug to the power cord (4). (The green and yellow wire is the ground wire.) 2.
  • Page 24 3. INSTALLATION <100V/400V system> (1) Power switch (2) Screws [2 pcs] Operator 4145M (3) Transformer box 2179B (4) Transformer box plates [2 pcs.] (5) Screw [with washer] (6) 3-pin power supply connector (7) Staples [6 pcs.] (8) Cord clamps [2 pcs.] (9) Power cord 1.
  • Page 25: Test Operation (Operating The Treadle)

    3. INSTALLATION 3-5. Test operation (Operating the treadle) CAUTION Do not touch any of the moving parts or press any objects against the machine while sewing, as this may result in personal injury or damage to the machine. <Turning on the power> 2114M Press the ON power switch (1).
  • Page 26: Adjusting The Treadle Operation

    3. INSTALLATION 3-6. Adjusting the treadle operation <Forward depression sensitivity adjustment> 4259M If the machine starts running at low speed when your foot is simply resting on the treadle, or if the treadle pressure is felt to be too weak, adjust the position (a to c) at which the treadle spring (1) is hooked onto the treadle lever (2).
  • Page 27: Preparation Before Sewing

    4. PREPARATION BEFORE SEWING 4. PREPARATION BEFORE SEWING 4-1. Installing the needle CAUTION Turn off the power switch before installing the needle. The machine may operate if the treadle is depressed by mistake, which could result in injury. 1. Turn the machine pulley to move the needle bar to its <T-8421C, 8422C, 8722C>...
  • Page 28: Removing The Bobbin

    4. PREPARATION BEFORE SEWING 4-2. Removing the bobbin CAUTION Turn off the power switch before removing the bobbin. The machine may operate if the treadle is depressed by mistake, which could result in injury. <Latch type> 1. Open the slide plates (1) by moving them to the right and left.
  • Page 29: Winding The Lower Thread

    4. PREPARATION BEFORE SEWING 4-3. Winding the lower thread CAUTION Do not touch any of the moving parts or press any objects against the machine while winding the lower thread, as this may result in personal injury or damage to the machine. 1.
  • Page 30: Installing The Bobbin

    4. PREPARATION BEFORE SEWING 4-4. Installing the bobbin CAUTION Turn off the power switch before installing the bobbin. The machine may operate if the treadle is depressed by mistake, which could result in injury. <Latch type> 2898M 1. Insert the bobbin (1) into the rotary hook (2) so that the winding direction is as shown in the illustration.
  • Page 31 4. PREPARATION BEFORE SEWING <Bobbin case type> <A> 1. Insert the bobbin (1) into the bobbin case (2) so that the winding direction is as shown in the illustration. 2. There are three types of cap (2) (<A>, <B> and <C>). Thread the thread by one of the following methods in accordance with the shape of the bobbin case (2) being used.
  • Page 32: Threading The Upper Thread

    4. PREPARATION BEFORE SEWING 4-5. Threading the upper thread CAUTION Turn off the power switch before threading the upper thread. The machine may operate if the treadle is depressed by mistake, which could result in injury. ・ Turn the machine pulley and raise the thread take-up (1) before threading the upper thread. This will make threading easier and it will prevent the thread from coming out at the sewing start.
  • Page 33 4. PREPARATION BEFORE SEWING <For all models except foundation specifications and T-8452C-405> Do not pass the thread through. <For foundation specifications Center and T-8452C-405> Pass the thread through. (Refer to p.54) If the tension discs are opened as follows, the thread will become easier to thread.
  • Page 34: Adjusting The Stitch Length

    4. PREPARATION BEFORE SEWING 4-6. Adjusting the stitch length 1. Unlock the stitch length dial (2) by turning the dial lock lever (1) to the right until a click is heard. 2. Turn the stitch length dial (2) clockwise or counterclockwise so that the desired stitch length is at the uppermost position on the dial.
  • Page 35: Corner Sewing Method (T-8452C, 8752C)

    4. PREPARATION BEFORE SEWING 4-9. Corner sewing method (T-8452C, 8752C) NOTE: If using this machine in place of a single-needle machine, remove the needle which is not being used. In such cases, do not use the procedures given below to stop the unused needle bar from moving, otherwise damage to the machine may result. 4-9-1.
  • Page 36: Using The G50 Operation Panel (Basic Operations)

    5. USING THE G50 OPERATION PANEL (BASIC OPERATIONS) 5. USING THE G50 OPERATION PANEL (BASIC OPERATIONS) 5-1. Names and functions • The operation panel keys cannot be operated while sewing is in progress. Select the keys and set the number of stitches before starting sewing. •...
  • Page 37 5. USING THE G50 OPERATION PANEL (BASIC OPERATIONS) Name label key When this key is pressed so that the indicator illuminates, fixed stitch sewing of the number of stitches (0-1999) in the E and F stitch number displays is carried out repeatedly. 4165M Pleat presser sewing key When this key is pressed so that the indicator illuminates, the number of backtack stitches...
  • Page 38: Sewing Start And End Backtack Stitches

    5. USING THE G50 OPERATION PANEL (BASIC OPERATIONS) 5-2. Sewing start and end backtack stitches 2911M Setting start backtack stitches For example, 3 stitches and 4 stitches 4175M Setting end backtack stitches Example: 4176M Start backtacking is carried out. After it has finished, normal sewing continues for as long as the treadle remains depressed.
  • Page 39: Sewing Continuous Backtack Stitches

    5. USING THE G50 OPERATION PANEL (BASIC OPERATIONS) 5-3. Sewing continuous backtack stitches 2185B Setting continuous backtack stitches Example: 4177M If the treadle is simply depressed continuously, the number of stitches set for A, B, C and D will be sewn in a single cycle, the thread will be trimmed automatically (models with thread trimmer) and then the needle bar will stop in the needle up position.
  • Page 40: Sewing Fixed Stitches

    5. USING THE G50 OPERATION PANEL (BASIC OPERATIONS) 5-4. Sewing fixed stitches 2912M Setting the number of fixed stitches 4178M Example: From 0 to 1999 stitches can be set. After the set number of stitches in E (fixed stitches) have been sewn, the sewing machine stops in the needle position that has been set by the needle up/down key (refer to p.
  • Page 41: Sewing Pleat Presser Stitches

    5. USING THE G50 OPERATION PANEL (BASIC OPERATIONS) 5-5. Sewing pleat presser stitches 2186B 4180M Example: From 0 to 1999 stitches can be set. If the treadle is continuously depressed and then you press the actuator switch while sewing is in progress, the number of backtack stitches set in E is sewn and then normal sewing resumes.
  • Page 42: Using The Lower Thread Counter

    5. USING THE G50 OPERATION PANEL (BASIC OPERATIONS) 5-6. Using the lower thread counter The lower thread counter can be used to let you know approximately how much lower thread is remaining. The value displayed by the lower thread counter display is reduced by 1 from the initial setting value each time the sewing machine sews 10 stitches, and a warning is given when the counter goes below “0”.
  • Page 43: Using The G50 Operation Panel (Advanced Operations)

    6. USING THE G50 OPERATION PANEL (ADVANCED OPERATIONS) 6. USING THE G50 OPERATION PANEL (ADVANCED OPERATIONS) The operations described in this section should only be carried out by a technician. 6-1. Names and functions These are used for making advanced operating settings.
  • Page 44: Adjusting The Needle Up Stop Position

    6. USING THE G50 OPERATION PANEL (ADVANCED OPERATIONS) 6-2. Adjusting the needle up stop position 4189M 2138M (While pressing the key (1), press the power ON switch.) “MorG xxx” will appear in orange in the main display (2). Selecting “UpoS xxx” “xxx”...
  • Page 45: Lock Key

    6. USING THE G50 OPERATION PANEL (ADVANCED OPERATIONS) 6-3. LOCK key When the power switch is turned on, the LOCK key (1) turns ON. (The icon (2) is illuminated.) In this state, the following three key operations are disabled so that the setting values cannot be changed accidentally. FUNC key (3) This key is used to make settings for various functions.
  • Page 46: Resetting All Settings To Their Defaults

    6. USING THE G50 OPERATION PANEL (ADVANCED OPERATIONS) 6-4. Resetting all settings to their defaults If the sewing machine stops operating normally, the cause may be that an incorrect setting may have been made for the memory data by means of memory switches, for instance. In such cases, it may be possible to restore normal operation by following the steps given below to initialize the memory setting data.
  • Page 47: Using The G10 Operation Panel (Basic Operations)

    7. USING THE G10 OPERATION PANEL (BASIC OPERATIONS) 7. USING THE G10 OPERATION PANEL (BASIC OPERATIONS) 7-1. Names and functions ・ The operation panel keys cannot be operated while sewing is in progress. Select the keys and set the number of stitches before starting sewing. ・...
  • Page 48: Sewing Start And End Backtack Stitches

    7. USING THE G10 OPERATION PANEL (BASIC OPERATIONS) 7-2. Sewing start and end backtack stitches 2911M Setting start backtack stitches For example, 3 stitches and 4 stitches 4200M Setting end backtack stitches Example: 4201M Start backtacking is carried out. After it has finished, normal sewing continues for as long as the treadle remains depressed.
  • Page 49: Sewing Continuous Backtack Stitches

    7. USING THE G10 OPERATION PANEL (BASIC OPERATIONS) 7-3. Sewing continuous backtack stitches 2185B Setting continuous backtack stitches Example: 4202M If the treadle is simply depressed continuously, the number of stitches set for A, B, C and D will be sewn in a single cycle, the thread will be trimmed automatically (models with thread trimmer) and then the needle bar will stop in the needle up position.
  • Page 50: Using The G10 Operation Panel (Advanced Operations)

    8. USING THE G10 OPERATION PANEL (ADVANCED OPERATIONS) 8. USING THE G10 OPERATION PANEL (ADVANCED OPERATIONS) The operations described in this section should only be carried out by a technician. 8-1. Changing the needle stop position This sets whether the needle bar stops in the needle up stop position or the needle down stop position when the treadle is returned to the neutral position and sewing stops.
  • Page 51: Slow Start

    8. USING THE G10 OPERATION PANEL (ADVANCED OPERATIONS) 8-2. Slow start When the slow start setting is enabled, the two stitches at the sewing start after thread trimming will be sewn at 700 sti/min. After this, the sewing speed corresponds to the treadle depression amount. This setting cannot be carried out if the lock function is on.
  • Page 52: Correction Sewing

    8. USING THE G10 OPERATION PANEL (ADVANCED OPERATIONS) 8-3. Correction sewing When correction sewing is enabled, sewing will be carried out at slow speed (250 sti/min) while the actuator switch is being pressed when the sewing machine is stopped. This setting cannot be carried out if the lock function is on. (For details on turning the lock function off, refer to “8-7. Lock function”.) Activating setting mode (Setting item)
  • Page 53: Thread Trimming Lock (Models With Thread Trimmer Only)

    8. USING THE G10 OPERATION PANEL (ADVANCED OPERATIONS) 8-4. Thread trimming lock (models with thread trimmer only) Thread trimming not locked Thread trimming locked Thread trimming is carried out. Thread trimming is not carried out. Thread trimming is Thread trimming is carried out.
  • Page 54: Setting The Maximum Sewing Speed

    8. USING THE G10 OPERATION PANEL (ADVANCED OPERATIONS) 8-5. Setting the maximum sewing speed ・ The maximum sewing speed can be set to a speed from 250 sti/min up to the maximum sewing speed which is set for the head detector unit. ・...
  • Page 55: Adjusting The Needle Up Stop Position

    8. USING THE G10 OPERATION PANEL (ADVANCED OPERATIONS) 8-6. Adjusting the needle up stop position 4217M 2138M (While pressing the key (1), press the power ON switch.) “MorG” will appear in the display (2). Selecting “UPoS” (Setting item) (Press once) 2193B Needle up stop position setting Example:...
  • Page 56: Lock Function

    8. USING THE G10 OPERATION PANEL (ADVANCED OPERATIONS) 8-7. Lock function DANGER Wait at least 5 minutes after turning off the power switch and disconnecting the power cord from the wall outlet before opening the cover of the control box. Touching areas where high voltages are present can result in severe injury.
  • Page 57: Sewing

    9. SEWING 9. SEWING CAUTION Attach all safety devices before using the sewing machine. If the machine is used without these devices attached, injury may result. Turn off the power switch at the following times. The machine may operate if the treadle is depressed by mistake, which could result in injury. When threading the needle When replacing the bobbin and needle When not using the machine and when leaving the machine unattended...
  • Page 58: Backtacking

    9. SEWING 9-2. Backtacking When the actuator switch (1) or the reverse lever (2) is 2916M pressed during sewing, the feed direction will be reversed. When it is released, the feed direction will return to normal. 2917M < Actuator switch rotation function > The actuator switch can be rotated 90 degrees as shown in the illustration.
  • Page 59: Sewing Condensed Stitches

    9. SEWING 9-3. Sewing condensed stitches If you press the actuator switch (1) or the reverse lever (2) while sewing is in progress, you can sew stitches (forward direction) with small stitch lengths. Before carrying out sewing, set the stitch length for condensed stitches as follows.
  • Page 60: Thread Tension

    10. THREAD TENSION 10. THREAD TENSION 10-1. Adjusting the thread tension Good even stitches Upper thread Lower thread 0572M Upper thread tension too weak or Increase the upper thread tension. lower thread tension too strong Decrease the lower thread tension. 0573M Upper thread tension too strong Decrease the upper thread tension.
  • Page 61: Adjusting The Presser Foot Pressure

    10. THREAD TENSION 10-2. Adjusting the presser foot pressure Correct stitches Upper thread 0894M Skipped stitches occur 0895M Increase the pressure. Uneven stitch length 0896M Stitches are puckered Decrease the pressure. 0897M The presser foot pressure should be as weak as possible, but strong enough so that the material does not slip.
  • Page 62: Adjusting The Presser Foot Floating Amount (Minute Lifting Amount)

    10. THREAD TENSION 10-3. Adjusting the presser foot floating amount (minute lifting amount) 3096M • When sewing stretch materials and materials with long pile, you can make minute adjustments to the floating amount for the presser foot (1) in accordance with the material.
  • Page 63: Adjusting The Thread Take-Up Amount

    10. THREAD TENSION 10-5. Adjusting the thread take-up amount The thread take-up amount is adjusted by how the thread is <For all models except foundation 2928M passed through the thread amount adjuster (1). specifications and T-8452C-405> <Using standard thread amount adjuster (1)>...
  • Page 64: Cleaning

    11. CLEANING 11. CLEANING CAUTION Turn off the power switch before carrying out cleaning. The machine may operate if the treadle is depressed by mistake, which could result in injury. Be sure to wear protective goggles and gloves when handling the lubricating oil and grease, so that they do not get into your eyes or onto your skin, otherwise inflammation can result.
  • Page 65: Lubricating Via The Oil Cover (Every 6 Months)

    11. CLEANING <Checking> 1. Replace the needle if it is bent or if the tip is broken. 2. Check that the upper threads have been threaded correctly. (Refer to page 24.) 3. Carry out a test sewing. 2196B <Draining lubricating oil> 1.
  • Page 66: Applying Grease (Semi Dry Specifications) [When "Grup" Appears

    11. CLEANING 11-3. Applying grease (Semi dry specifications) [When “GrUP” appears ... When using the G50 operation panel] If “GrUP” flashes in the display (1) and the buzzer sounds when the power ON switch is pressed, it means that it is time to add grease.
  • Page 67 11. CLEANING <Applying grease> Use Brother-specified “Grease unit (SA8837-001)”. 1. Using the tube 4087M 2. Applying grease Follow the procedure below to apply grease to the places indicated by arrows on the next page. Grease Insert the tip of the nozzle Apply grease without...
  • Page 68 11. CLEANING 2201B Turn the machine pulley until the screw (1) can be seen. Use the tip of a screwdriver or similar to apply 5-10 mm beads of grease to the slide block slider (2). 4 places at top, bottom, left and right of the slide block (3) * Pour oil into the oil cover at the same time.
  • Page 69: Applying Grease (Semi Dry Specifications) [When "Grup" Appears

    11. CLEANING 11-4. Applying grease (Semi dry specifications) [When “GrUP” appears ... When using the G10 operation panel] If “GrUP” flashes in the display (1) and the buzzer sounds when the power ON switch is pressed, it means that it is time to add grease.
  • Page 70 11. CLEANING <Applying grease> Use Brother-specified “Grease unit (SA8837-001)”. 1. Using the tube 4087M 2. Applying grease Follow the procedure below to apply grease to the places indicated by arrows on the next page. Grease Insert the tip of the nozzle Apply grease without...
  • Page 71 11. CLEANING 2201B Turn the machine pulley until the screw (1) can be seen. Use the tip of a screwdriver or similar to apply 5-10 mm beads of grease to the slide block slider (2). 4 places at top, bottom, left and right of the slide block (3) * Pour oil into the oil cover at the same time.
  • Page 72: Adjusting The Rotary Hook Lubrication Amount

    12. ADJUSTING THE ROTARY HOOK LUBRICATION AMOUNT 12. ADJUSTING THE ROTARY HOOK LUBRICATION AMOUNT CAUTION Be careful not to touch your fingers or the lubrication amount check sheet against moving parts such as the rotary hook or the feed mechanism when checking the amount of oil supplied to the rotary hook, otherwise injury may result.
  • Page 73: Standard Adjustment

    13. STANDARD ADJUSTMENT 13. STANDARD ADJUSTMENT CAUTION Use both hands to hold the machine head when Maintenance and inspection of the sewing machine tilting it back or returning it to its original position. If should only be carried out by a qualified technician. only one hand is used, the weight of the machine Ask your Brother dealer or a qualified electrician to head may cause your hand to slip, and your hand...
  • Page 74: Thread Take-Up Amount For Thread Take-Up Spring

    13. STANDARD ADJUSTMENT 13-2. Thread take-up amount for thread take-up spring The standard thread take-up length for thread take-up 3014M < Measurement method > springs R (1) and L (2) is 7 mm. You can adjust the thread take-up amounts by changing the heights of the stopper [right] (3) and the stopper [left] (4).
  • Page 75: Thread Take-Up Spring Tension

    13. STANDARD ADJUSTMENT 13-3. Thread take-up spring tension The standard tensions for the thread take-up spring R (1) and < Measurement method > thread take-up spring L (2) are as follows depending on sewing machine specifications. Do not pass thread through For foundation (-T[]F) 0.25N thread take-up...
  • Page 76: Clearance Between Rotary Hook And Needle Plate

    (2) is adjusted as follows at the time of shipment from the factory. Model Distance (A) Without thread trimming 0.9 – 1.2 mm T-8421C With thread trimming T-8422C T-8722C 1.4 – 1.7 mm T-8452C T-8752C 3054M • Check clearance (A) each time parts such as the rotary 3055M hook (1) and the needle plate (2) that affect clearance (A) are replaced.
  • Page 77: Clearance Between Rotary Hook And Opener

    13. STANDARD ADJUSTMENT 13-5. Clearance between rotary hook and opener 1. Loosen the set screw (3) and move the opener (1) to the left or right to adjust so that the clearance between the rotary hook (2) and the opener (1) is 0.1–0.3 mm when the opener (1) is pulled as far as it will go in the direction of the arrow.
  • Page 78: Needle And Rotary Hook Timing

    13. STANDARD ADJUSTMENT 13-7. Needle and rotary hook timing 1. Set the stitch length dial to the actual length of the stitches to be sewn. Standard stitch length Specifications Stitch length dial -T[]F -[][]3 -405, -407 2. Remove the rubber cap (1). 3.
  • Page 79 12. Remove the tape that is securing the machine pulley. 3042M <For T-8421C, T-8422C and T-8722C> 13. Use an oil-based marker pen to color in the hollow of the needle. 14. With the needle raised, turn the machine pulley forward...
  • Page 80: Installing The Feed Dog

    13. STANDARD ADJUSTMENT <For T-8452C and T-8752C> 13. Use an oil-based marker pen to color in the hollow of the needle. 14. With the needle raised, turn the machine pulley forward Color in while pushing the needle against the rotary hook tip (15) with your finger to make a mark from the rotary hook tip (15) in the hollow of the needle.
  • Page 81: Feed Dog Position

    13. STANDARD ADJUSTMENT 13-9. Feed dog position < Forward-back position adjustment > 3061M Carry out this adjustment if the needle and the needle hole in the feed dog are not positioned correctly even though the clearance between the needle bar and the presser bar (13.3–13.7 mm) is correct.
  • Page 82: Feed Dog Height

    13. STANDARD ADJUSTMENT 13-10. Feed dog height Turn the machine pulley forward until the feed dog (1) is at its highest position, and then adjust so that the feed dog (1)protrudes 0.9–1.1 mm from the top of the needle plate (2). 3064M 1.
  • Page 83: Feed Dog Angle

    13. STANDARD ADJUSTMENT 13-11. Feed dog angle The standard angle for the feed dog is when the mark (2) on the feed bar shaft (1) is aligned with the reference line (4) on the feed rocker base arm (3). 1. Tilt back the machine head. 2.
  • Page 84: Troubleshooting

    14. TROUBLESHOOTING 14. TROUBLESHOOTING Please check the following points before calling for repairs or service. If the following remedies do not fix the problem, turn off the power switch and consult a qualified technician or the place of purchase. DANGER Wait at least 5 minutes after turning off the power switch and disconnecting the power cord from the wall outlet before opening the face plate of the control box.
  • Page 85 14. TROUBLESHOOTING Problem Possible cause Page Skipped stitches occur Is the needle tip bent? Is the needle tip blunt? while sewing If the needle tip is bent or broken, replace the needle. Is the needle properly installed? If it is incorrect, install the needle correctly. Is the machine properly threaded? If it is incorrect, thread the thread correctly.
  • Page 86 14. TROUBLESHOOTING Problem Possible cause Page Uneven seam Is the presser foot pressure too weak? Adjust the presser foot pressure. Is the feed dog too low? Adjust the feed dog height. Is the bobbin scratched? If the bobbin is damaged, smooth it with an oiled grindstone or replace it.
  • Page 87 14. TROUBLESHOOTING Problem Possible cause Page Upper and lower threads Is the needle bent or is the needle tip broken? are breaking. Replace the needle if it is bent or broken. Is the needle properly installed? If it is incorrect, install the needle correctly. Is the machine properly threaded? If it is incorrect, thread the thread correctly.
  • Page 88 14. TROUBLESHOOTING Problem Possible cause Page Machine does not operate Is the sewing speed setting or backtack speed setting incorrect? at high speed. Use the sewing speed control keys to set the high speed. Machine stops during Is the fixed stitch key turned on? sewing.
  • Page 89: Error Code Displays

    14. TROUBLESHOOTING 14-2. Error code displays If an error code appears on the operation panel display 1. Make a note of the error code and then turn off the power. 2. After the operation panel display has turned off, eliminate the cause of the error and then turn the power back on.
  • Page 90 14. TROUBLESHOOTING Error code Possible cause Page E090 ・ Is the 4-pin treadle connector inside the control box disconnected? Press the power OFF switch, and then check that the 4-pin treadle connector is Treadle connected to connector P14 on the main PCB. connector is not If there is a broken wire in the cord of the treadle connector, replace the treadle connected.
  • Page 91 14. TROUBLESHOOTING Error code Possible cause Page E150 ・ This is displayed when the motor becomes abnormally hot and the temperature protection has activated. Motor is After the temperature has dropped, press the power ON switch and operate the overheating. sewing machine as normal.
  • Page 92 14. TROUBLESHOOTING Error code Possible cause Page E701 ・ Does the power supply voltage match the control box voltage specifications? Check that the voltage matches. Abnormally high ・ Is the power supply voltage abnormally high? power supply Check the power supply voltage. voltage.
  • Page 93: Segment Display

    15. 7-SEGMENT DISPLAY 15. 7-SEGMENT DISPLAY 4268M T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 94: Instruction Manual

    INSTRUCTION MANUAL © 2010 Brother Industries, Ltd. All Rights Reserved. T-8421C, 8422C, 8452C, 8722C, 8752C SB1410-001 E This is the original instructions. 2010.05. B (1)

This manual is also suitable for:

T-8722cT-8752cT-8421cT-8452c