Brother T-8421C Instruction Manual
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Brother T-8421C Instruction Manual

Twin needle direct drive lock stitcher
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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-8421C

  • 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

    ) indicates something that you must do. The picture inside the circle indicates the · · · · · nature of the thing that must be done. (For example, the symbol at left means “you must make the ground connection”.) T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 4 Contact your Brother dealer or a qualified electrician for any electrical work that may need to Secure the table so that it will not move when tilting be done.

  • Page 5: Maintenance And Inspection

    If the table moves, it may crush your feet or cause other injuries. Ask your Brother dealer or a qualified electrician to carry out any maintenance and inspection of the Use both hands to hold the machine head when electrical system.
  • Page 6 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

    5-4. Sewing fixed stitches ........31 10-4. Adjusting the trailing length after thread 5-5. Sewing pleat presser stitches......32 trimming (models with thread trimmer only) 5-6. Using the lower thread counter ...... 33 ..............53 10-5. Adjusting the thread take-up amount....54 T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 9 13-8. Installing the feed dog ........71 13-9. Feed dog position ......... 72 13-10. Feed dog height.......... 73 13-11. Feed dog angle........... 74 14. TROUBLESHOOTING......14-1. Sewing ............75 14-2. Error code displays........80 15. 7-SEGMENT DISPLAY....... T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 10: Machine Specifications

    Fixed needle bar Split needle bar Thread trimmer ○ Quick reverse ○ ○ Thread wiper ○ Lubrication type Minimum lubrication Semi dry Heavy-weight Light-weight and Heavy-weight materials Foundation medium-weight materials (For extra thick materials thread) T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 11 1,000 sti/min Max. stitch length 7 mm Presser foot Lifting lever 7 mm height Knee lifter 10 mm Feed dog height 1 mm Needle (DP×5) #11–#16 #14–#22 Motor AC servo motor (4-pole, 550W) Control circuit Microprocessor T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 12: Names Of Major Parts

    Power switch Stitch length dial (10) Reverse lever (11) Oil gauge window (12) Machine pulley (13) Operation panel (14) Cotton stand (15) Stop lever (T-8452C, 8752C ) Safety devices (16) Thread take-up cover (17) Finger guard T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 13: Installation

    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. Use both hands to hold the machine head when tilting it back or returning it to its original position.

  • Page 14: Installation

    2170B 3-2. Installation 1. Control box (1) Control box (2) Bolts [3 pcs] (3) Nuts [3 pcs] (4) Spring washers [3 pcs] (5) Washers [3 pcs] 2. Connecting rod (6) Connecting rod (7) Nut 4127M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 15: Oil Pan

    (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

    8. Cotton stand (1) Cotton stand NOTE: Securely tighten the nut (4) so that the two rubber cushions (2) and the washer (3) are securely clamped and so that the cotton stand (1) does not move. 2878M T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 17 (5) is at the desired position within a distance of 13 mm of the needle plate when the knee liter plate (1) is fully pressed. 9. After adjustment is completed, securely tighten the nut (9). Within 13 mm 2882M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 18: Lubrication

    Use only the lubricating oil <NIPPON OIL CORPORATION Sewing Lube 10N; VG10> specified by Brother. * If this type of lubricating oil is difficult to obtain, the recommended oil to use is <Exxon Mobil Essotex SM10; VG10>.
  • Page 19 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 2887M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 20: Connecting The Cords

    Touching areas where high voltages are present can result in severe injury. CAUTION Contact your Brother dealer or a qualified electrician When securing the cords, do not bend the cords for any electrical work that may need to be done.
  • Page 21 (2) using the repeat cable tie (1), otherwise vibration from the sewing machine may cause the cords become disconnected, <Securing> which can cause problems with the operation of the control box. Cords <Closing the cover> 4141M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 22: Other Cords

    Take care when tapping in the staples (3) to make sure that they do not pierce the cords. extension cords, otherwise machine operation <Seen from underneath table> problems may result. Control box Green and yellow wire (ground wire) 4144M T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 23 NOTE: Take care when tapping in the staples (5) to make sure that they do not pierce the cords. extension cords, otherwise machine operation problems may result. Green and yellow wire (ground wire) 2178B T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 24 NOTE: Take care when tapping in the staples (7) to make sure that they do not pierce the cords. extension cords, otherwise machine operation problems may result. Green and yellow wire (ground wire) 2380B T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 25: Test Operation (Operating The Treadle)

    NOTE: If the sewing machine operates when the treadle (3) is depressed while the machine head is tilted back, the safety switch is probably faulty. Contact the place of purchase. 2117M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 26: Adjusting The Treadle Operation

    (6) from the position in figure A to the position in figure B. The treadle stroke will then be increased by approximately 27 %. At this time, the treadle forward and backward depression sensitivity will change, so readjust if necessary. 4260M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 27: Preparation Before Sewing

    3. Insert the needle (2) straight in as far as it will go so that the long groove is facing inward, and then securely tighten the screws (1). Long groove 2461B <T-8452C, 8752C> Long groove 2462B T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 28: Removing The Bobbin

    1. Open the slide plates (1) by moving them to the right and left. 2. Lift up the latch (2) of the rotary hook, and then remove the bobbin case (3). 3. Remove the bobbin. 2464B T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 29: Winding The Lower Thread

    NOTE: More thread The amount of thread wound onto the bobbin should be a maximum of 80 % of the bobbin capacity. Less thread 2123M 2124M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 30: Installing The Bobbin

    There is an anti-spin spring (6) inside the rotary hook. The anti-spin spring (6) prevents the bobbin from racing at times such as during thread trimming. Use bobbins (1) made of light alloy as specified by BROTHER. 2466B T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 31 There is an anti-spin spring (10) inside the rotary hook. The anti-spin spring (10) prevents the bobbin from racing at times such as during thread trimming. Use bobbins (1) made of light alloy as specified by BROTHER. 2468B T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 32: Threading The Upper Thread

    ・ 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. ・ Thread the left-side thread first. T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 33 Pass the thread on the inside of the tab (3). Specifications indicated by the * mark include arm thread guide D (4) and felt (5). When using polyester thread, install these components and thread the thread as shown in the illustration. 2183B T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 34: Adjusting The Stitch Length

    1. Press the thread wiper switch (1) to the side. 2184B 2. Press the thread wiper key (2) on the operation panel so that the indicator illuminates. After thread trimming is carried out, the thread wiper (3) will pull up the thread. 2470B T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 35: Corner Sewing Method (T-8452C, 8752C)

    The number of stitches of the outer needle varies according to the combination of sewing angle and stitch length. [Example] For a sewing angle of 40° and a stitch length of 2.9 mm, the number of stitches becomes 6. T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 36: Using The G50 Operation Panel (Basic Operations)

    4163M Fixed stitch key When this key is pressed so that the indicator illuminates, the number of stitches (0-1999) in the E stitch number display is sewn, and then the sewing machine stops automatically. 4164M T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 37 If you press the thread trimming lock key (13) so that its indicator illuminates while the indicator of the thread wiper key (18) is illuminated, the indicator of the thread wiper key (18) will switch off. T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 38: Sewing Start And End Backtack Stitches

    • If the indicator of the thread trimming lock key is illuminated, the sewing machine will stop in the needle up position without thread trimming being carried out. 2160M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 39: Sewing Continuous Backtack Stitches

    When the AUTO key is pressed to turn on the automatic sewing function, operation will be carried out automatically from continuous backtack sewing through to thread trimming (models with thread trimmer) just by depressing the treadle once, without needing to keep it depressed continuously. T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 40: Sewing Fixed Stitches

    • If changing the number of end backtack stitches in C and D, press the fixed stitch key to temporarily turn off the fixed stitch function before making the change. (The CD display will show the number of stitches and the setting can then be changed.) T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 41: Sewing Pleat Presser Stitches

    • If changing the number of end backtack stitches indicated in C and D, press the pleat presser sewing key to turn off the pleat presser sewing function before making the change. (The CD display will show the number of stitches and the setting can then be changed.) T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 42: Using The Lower Thread Counter

    If you press the RESET key (2), the warning icon (1) will disappear and sewing will be possible when the treadle is depressed. 4. If you press and hold the RESET key (2) for 2 seconds or more, the display will return to the initial value. T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 43: Using The G50 Operation Panel (Advanced Operations)

    • When the needle up icon (24) is illuminated, the needle bar stops in the up position. • When the needle down icon (25) is illuminated, the needle bar stops in the down position. 4188M 2207M 2208M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 44: Adjusting The Needle Up Stop Position

    Becomes higher Becomes lower 2188B 2138M 2139M The setting values will be memorized. 4192M Normal sewing machine operation will then be possible. 4193M * For details on other adjustment items, refer to the Service Manual. T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 45: Lock Key

    ENTER key (4) This key is used to accept function settings. MAX key (5) This key is used to change the maximum sewing speed. * Refer to the Service Manual for details on using these keys. 4194M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 46: Resetting All Settings To Their Defaults

    4196M 2138M 2139M Once initialization is complete, the main display will return to green. (Press for 2 seconds or more) 4192M Initialization mode will be exited and normal sewing machine operation will then be possible. 4193M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 47: Using The G10 Operation Panel (Basic Operations)

    “8-4. Thread trimming lock (models with thread trimmer only)”.) ・ If thread trimming lock is set when the indicator of this key is illuminated, the indicator of the thread wiper key (6) will switch off. 4174M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 48: Sewing Start And End Backtack Stitches

    ・ If the treadle is depressed backward before sewing of the set number of start backtack stitches is complete, end backtacking will not be carried out. ・ If thread trimming lock is set, the sewing machine will stop in the needle up position without thread trimming being carried out. 2160M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 49: Sewing Continuous Backtack Stitches

    ・ If thread trimming lock is set, the sewing machine will stop in the needle up position without thread trimming being carried out. 2159M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 50: Using The G10 Operation Panel (Advanced Operations)

    4204M The setting will be stored and the display will (Setting item) return to the setting item. 4205M Setting mode will be exited and normal operation will be possible. 4206M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 51: Slow Start

    4208M 2138M 2139M The setting will be stored and the display will (Setting item) return to the setting item. 4209M Setting mode will be exited and normal operation will be possible. 4206M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 52: Correction Sewing

    4208M 2138M 2139M The setting will be stored and the display will (Setting item) return to the setting item. 4211M Setting mode will be exited and normal operation will be possible. 4206M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 53: Thread Trimming Lock (Models With Thread Trimmer Only)

    4208M 2138M 2139M The setting will be stored and the display will (Setting item) return to the setting item. 4213M Setting mode will be exited and normal operation will be possible. 4206M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 54: Setting The Maximum Sewing Speed

    A and B columns will be disabled. If the MAX key is pressed once more, the indicator of the MAX key will switch off and normal key operations can then be carried out. T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 55: Adjusting The Needle Up Stop Position

    The setting will be stored and the display will return (Setting item) to the setting item. 4220M Normal sewing machine operation will then be possible. 4206M * For details on other adjustment items, refer to the Service Manual. T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 56: Lock Function

    “in.AL” will appear in the display (1). press the power ON switch.) Once initialization is complete, the “in.AL” appearing in the display (1) will disappear and normal sewing machine operation will then be possible. (Press for 2 seconds or more) 4206M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 57: Sewing

    The power indicator (2) will illuminate. 4. Use the operating panel to carry out the programming which is necessary for sewing. (Refer to the chapter on “5./7. Using the operating panel”.) 5. Depress the treadle to start sewing. 2182B T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 58: Backtacking

    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. Select the position (A or B) that is easier to use. 2918M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 59: Sewing Condensed Stitches

    (1) or reverse lever (2) is being pressed.) * To stop sewing condense stitches and return to using the backtack function, lower the stopper (6) so that it does not touch the reverse stitching lever plate (7). 2921M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 60: Thread Tension

    After the lower thread tension has been adjusted, adjust the upper thread tension so that a good, even stitch is obtained. 1. Lower the presser foot. 2. Adjust by turning the tension nut (2). Becomes stronger Becomes weaker Becomes weaker Becomes stronger 2924M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 61: Adjusting The Presser Foot Pressure

    2. Turn the presser adjusting screw (2) to adjust the presser foot pressure. 3. Tighten the adjusting nut (1). Reference values Adjusting screw height For foundation Approx. 34mm For light-weight and medium- weight Approx. 34mm materials For heavy-weight Approx. 29mm materials 2925M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 62: Adjusting The Presser Foot Floating Amount (Minute Lifting Amount)

    Longer Shorter reduced; if the tension is reduced, the lengths will be increased. Adjust by turning the pretension (1). Trailing thread 2926M 2258B T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 63: Adjusting The Thread Take-Up Amount

    Start of movement The thread take-up amount required will vary depending on the type of thread, the thickness of the material and the stitch length, so adjust the thread take-up amount to suit the sewing conditions. 3019M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 64: Cleaning

    <Filling the oil tank> Use only the lubricating oil <NIPPON OIL CORPORATION Sewing Lube 10N; VG10> specified by Brother. * If this type of lubricating oil is difficult to obtain, the recommended oil to use is <Exxon Mobil Essotex SM10; VG10>.

  • Page 65: Lubricating Via The Oil Cover (Every 6 Months)

    Use only the lubricating oil <NIPPON OIL CORPORATION 2190M Sewing Lube 10N; VG10> specified by Brother. * If this type of lubricating oil is difficult to obtain, the recommended oil to use is <Exxon Mobil Essotex SM10; VG10>.

  • Page 66: Applying Grease (Semi Dry Specifications) [When "Grup" Appears

    If this happens, apply grease and carry out the reset procedure. * If you continue to use the sewing machine after carrying out the reset procedure but without applying grease, problems with the sewing machine may result. T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 67 ・ When using the grease again, remove any old grease from inside the nozzle first. (Store the tube away carefully once the tube has been opened, otherwise the grease remaining inside the tube may deteriorate, and this may affect its lubricating performance.) 2937M T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 68 4. The display (3) will change to “GuCt 0”. 5. Press the FUNC key (5). The display (3) will change to stitch number display mode and treadle operation will be possible. (This completes the reset procedure.) T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 69: Applying Grease (Semi Dry Specifications) [When "Grup" Appears

    If this happens, apply grease and carry out the reset procedure. * If you continue to use the sewing machine after carrying out the reset procedure but without applying grease, problems with the sewing machine may result. T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 70 ・ When using the grease again, remove any old grease from inside the nozzle first. (Store the tube away carefully once the tube has been opened, otherwise the grease remaining inside the tube may deteriorate, and this may affect its lubricating performance.) 2937M T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 71 6. The display (1) will change to “ 0”. 7. Press the thread wiper key (6). The display (3) will change to stitch number display mode and treadle operation will be possible. (This completes the reset procedure.) 2261B 2138M 2139M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 72: Adjusting The Rotary Hook Lubrication Amount

    * Turn the adjusting screw (1) and check the lubrication amount repeatedly until the lubrication amount is correct. 4. Check the lubrication amount again after the sewing machine has been used for approximately two hours. 2476B T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 73: Standard Adjustment

    Ask your Brother dealer or a qualified electrician to head may cause your hand to slip, and your hand carry out any maintenance and inspection of the may get caught.

  • Page 74: Thread Take-Up Amount For Thread Take-Up Spring

    Trailing thread 3016M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 75: Thread Take-Up Spring Tension

    Thread take-up spring L (2) [for left thread] 1. Loosen the tension nut (5). 2. Use a small screwdriver to turn the tension stud (6) to Stronger adjust the tension. 3. Tighten the tension nut (5). 3017M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 76: Clearance Between Rotary Hook And Needle Plate

    • The right upper thread may be cut too short (models with thread trimmer). * These problems may occur particularly if the stitch length is large or when carrying out thread trimming during chaining-off. 3056M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 77: Clearance Between Rotary Hook And Opener

    Do not turn the presser bar (8) at this time. 5. Tighten the screw (7). 6. Turn the presser adjusting screw (4) to adjust the presser foot pressure, and then tighten the nut (3). Approx. 7mm 3059M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 78: Needle And Rotary Hook Timing

    If the needle bar lift amount is too small Lower feed Needle feed • Skipped stitches and thread breakages will occur. • The upper thread trailing length will be too short (models 3040M with thread trimmer). T-8421C, 8422C, 8452C, 8722C, 8752C...
  • 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

    (4) touches the bottom of the feed dog (1). 3. Tighten the nut (5) to secure the set screw (4). Touch * The set screw (4) is not used for installing the feed dog at an angle. 3060M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 81: Feed Dog Position

    (5) and (6). If the needle plate and the feed dog are touching, loosen the screw (1) and move the feed rocker base arm (3) sideways Should not be to adjust. touching at any points 3063M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 82: Feed Dog Height

    • The feed dog may touch the movable knife (models with thread trimmer). • Large variations in stitch length may occur at slow and fast sewing speeds. Lower Higher 3066M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 83: Feed Dog Angle

    * In addition, when the angle of the feed dog is adjusted, the height of the feed dog will also change, so readjust the height of the feed dog. 3067M T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 84: Troubleshooting

    Pull out the lower thread to check that there is no slackness in the thread tension, or replace the bobbin or bobbin case. Is the thread take-up amount too large? Adjust the thread take-up amount. 0977M T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 85 If sewing light or medium-weight materials, is a presser foot with slots on the underside or grooved feed dog being used? Use a presser foot without slots. Use a feed dog without grooves. Grooves Slot 2944M 2946M T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 86 Attach the anti-spin spring. • Is the bobbin turning smoothly? If the bobbin is not turning smoothly, replace the bobbin. Is a bobbin other that the light-alloy bobbins specified by Brother being used? Use only bobbins which are specified by Brother. •...
  • Page 87 0469M Machine does not operate Is the power supply connector when power is turned on disconnected from the control and treadle is pressed. box? Insert connector securely. • 2197B T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 88 P7 inside the control box disconnected? Insert connector securely. 4264M “GrEASEUP” flashes on This display is to notify you that it is time to apply grease. the operation panel when Apply grease. the power is turned on. T-8421C, 8422C, 8452C, 8722C, 8752C...

  • Page 89: Error Code Displays

    ・ Was the actuator switch being pressed when the power ON switch was pressed? Press the power OFF switch and check that the actuator switch is not being pressed ・ There is a problem with the actuator switch. Replace the actuator switch. T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 90 Replace the motor or the control box. E132 ・ Problem with motor. Replace the motor. Problem with ・ Problem with drive PCB. motor operation. Replace the control box. E140 ・ Motor reverse operation was detected. Replace the motor. Motor reverse operation. T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 91 ・ Is the 6-pin head detector unit connector inside the control box disconnected? Press the power OFF switch, and then check that the 6-pin head detector unit Head detector unit connector is connected to connector P8 on the main PCB. connection error. T-8421C, 8422C, 8452C, 8722C, 8752C...
  • Page 92 Press the power OFF switch and set DIP switch No. 4 to OFF. If an error code that is not listed above appears or if carrying out the specified remedy does not solve the problem, contact the place of purchase. T-8421C, 8422C, 8452C, 8722C, 8752C...

  • 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 SB1461-001 E This is the original instructions. 2010.05. B (1)

This manual is also suitable for:

T-8422cT-8752cT-8452cT-8722c

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