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Brother S-710A Service Manual

Brother single needle direct drive straight lock stitcher with thread trimmer
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SL-710A
DB2-DD7100A
DB2-DD7100
Please read this manual before making any adjustments.
SINGLE NEEDLE DIRECT DRIVE STRAIGHT LOCK STITCHER
WITH THREAD TRIMMER
SERVICE MANUAL

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  Summary of Contents for Brother S-710A

  • Page 1 SERVICE MANUAL SL-710A DB2-DD7100A DB2-DD7100 Please read this manual before making any adjustments. SINGLE NEEDLE DIRECT DRIVE STRAIGHT LOCK STITCHER WITH THREAD TRIMMER...
  • Page 2: Safety Instructions

    As a result of research and improvements regarding this product, some details of this manual may not be the same as those for the product you purchased. If you have any questions regarding this product, please contact a Brother dealer. SAFETY INSTRUCTIONS...
  • Page 3: Notes On Safety

    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 4: Maintenance And Inspection

    Ask your Brother dealer or a qualified electrician to carry out any maintenance and inspection of the If the power switch needs to be left on when electrical system.
  • Page 5: 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. Thread take-up cover...
  • Page 6: Table Of Contents

    INDEX 1. SPECIFICATIONS........6. ASSEMBLY ............29 6-1. Stitch length dial, reverse stitching lever 2. OPTIONAL PARTS ........and feed regulator mechanism....29 3. NOTES ON HANDLING ......6-2. Rotary hook shaft, thread trimmer cam and gear..........31 4. MECHANICAL DESCRIPTIONS ..... 6-3. Plunger ............31 4-1.
  • Page 7 7. ADJUSTMENTS 17. SPEED SETTING METHODS ..........63 ....100 7-1. Adjusting the thread tension spring .....63 17-1.Types of speed settings......100 7-2. Adjusting arm thread guide R......64 17-2.Setting method.......... 100 7-3. Adjusting the presser foot height....64 17-3.Checking the speed settings..... 101 7-4.
  • Page 8: Specifications

    1. SPECIFICATIONS 1. SPECIFICATIONS Machine head Models Thread trimmer Solenoid DD7100- Thread wiper Solenoid DD7100- Quick reverse Solenoid Automatic presser lifter Solenoid SL-710A- Bobbin thread detector For light-weight and For medium-weight For heavy-weight difficult-to-sew materials materials Sewing speed 220 - 4,000 rpm 220 - 5,000 rpm * 220 - 3,500 rpm Start backtacking and continuous backtacking...
  • Page 9 1. SPECIFICATIONS Operation panel Operation panel Part code B-40 J80627-001 B-100 J80629-001 SL-710A...
  • Page 10: Optional Parts

    2.OPTIONAL PARTS 2. OPTIONAL PARTS Part name Part code DD7100A, 710A S80008-001 Presser foot lifting solenoid set A With knee switch DD7100 183959-001 DD7100A, 710A S80009-001 Presser foot lifting solenoid set B Without knee switch DD7100 183960-001 DD7100A, 710A S80007-001 Lower thread detector set DD7100 183955-001...
  • Page 11: Notes On Handling

    3. NOTES ON HANDLING 3. NOTES ON HANDLING About the machine set-up location • Do not set up this sewing machine near other equipment such as televisions, radios or cordless telephones, otherwise such equipment may be affected by electronic interference from the sewing machine.
  • Page 12: Mechanical Descriptions

    4. MECHANICAL DESCRIPTIONS 4. MECHANICAL DESCRIPTIONS The mechanisms operate in the order of the numbers given in the illustrations. 4-1. Upper shaft and needle bar mechanism Needle take-up lever Upper shaft Thread take-up crank Rotor Pulley Needle bar clamp Slide block Needle bar The needle bar is guided by the needle bar bush U (1) and needle bar bush D (2).
  • Page 13: Feed Mechanism

    4. MECHANICAL DESCRIPTIONS 4-3. Feed mechanism 1628M Vertical movement of feed bar Pulley F-lifting eccentric wheel assy Feed bar Lower shaft Horizontal movement of feed bar Pulley Level feed eccentric wheel Level feed Lower shaft connecting rod Feed bar Feed regulator assy Feed rocker bracket arm Feed 1629M...
  • Page 14: Quick Reverse Mechanism

    4. MECHANICAL DESCRIPTIONS 4-4. Quick reverse mechanism 1630M Quick reverse solenoid Solenoid lever ctuator Shaft Handle shaft arm Connecting rod Stud arm F-regulator connecting rod S Feed regulator assy Feed rocker shaft Joint Feed rocker arm Feed rocker arm link <Reverse feed>...
  • Page 15: Lubrication Mechanism (Thread Take-Up Lever And Rotary Hook)

    4. MECHANICAL DESCRIPTIONS 4-5. Lubrication mechanism (Thread take-up lever and rotary hook) The lubrication mechanism for this sewing machine is a dry head method, with the oil supplied from a tank. The oil level can be checked through the oil gauge window, without needing to tilt back the machine head or operate the sewing machine.
  • Page 16 4. MECHANICAL DESCRIPTIONS DD7100 When adding the lubricating oil for the first time after unpacking the sewing machine, pour 120 ml of lubricating oil in through oil filler hole (1). The oil gauge in the oil gauge window (2) will rise as far as the upper reference line. (Refer to page 59 for details on the lubrication method.) 1637M Upper reference line...
  • Page 17: Thread Trimmer Mechanism

    4. MECHANICAL DESCRIPTIONS 4-6. Thread trimmer mechanism 4-6-1. Thread trimmer operation The figure below shows the thread trimmer without the high-speed rotary hook. 1) When the thread trimmer signal is received Solenoid plunger Solenoid lever Thread trimmer cam lever shaft Roller (Moves over thread trimmer cam (1)) 1639M...
  • Page 18 4. MECHANICAL DESCRIPTIONS 3) Thread trimming complete stop 1641M Solenoid Thread trimmer lever plunger <1> Thread trimmer lever <2> Forked shaft <3> Roller block Solenoid lever <4> Roller Thread trimmer lever Thread trimmer holder Thread trimmer connecting rod Spring Movable knife 4) Thread trimmer safety device When the movable knife does not return to its original position, the mechanism operates as shown in the illustration below to move the movable knife to a position where it will not touch the needle.
  • Page 19: Upper And Lower Thread Trimming

    4. MECHANICAL DESCRIPTIONS 4-6-2. Upper and lower thread trimming Movable knife 1643M 1644M 1. When the needle rises 1.8mm (2.2mm with heavy- 2.The thread trimmer signal is then relayed, and the weight materials) above the down position the rotary thread trimmer cam drives the movable knife. The hook point catches the loop formed by the needle.
  • Page 20: Tension Release Mechanism

    4. MECHANICAL DESCRIPTIONS 4-7. Tension release mechanism 1649M When a thread trimming signal is input Discs Disc presser Tension release plate Tension Thread trimmer release wire solenoid Solenoid lever Tension release stud Bolt 1650M Seen from underneath Tension release wire 4 Tension Thread trimmer release wire...
  • Page 21: Thread Wiper Mechanism

    4. MECHANICAL DESCRIPTIONS 4-8. Thread wiper mechanism When a thread wiping signal is received after the thread is trimmed Thread wiper solenoid (Spring) Thread wiper rod Thread wiper crank assy Thread wiper 1654M 4-9. Presser foot lifter mechanism (-9[][], Option) (built into machine head) 1655M When knee switch is pressed Knee lifter connecting rod...
  • Page 22: Lower Thread Detector Mechanism

    4. MECHANICAL DESCRIPTIONS 4-10.Lower thread detector mechanism • The lower thread detector mechanism has been designed for materials which do not allow thread jointing or re-sewing to be carried out when the lower thread runs out. • The lower thread is detected after the thread is trimmed, and the amount of lower thread remaining is displayed on the operation panel.
  • Page 23: Disassembly

    5. DISASSEMBLY 5. DISASSEMBLY DANGER Wait at least 10 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 24: Connectors

    5. DISASSEMBLY 5-2. Connectors 1662M [Machine connector] Operating panel connector Synchronizer connector Lower thread detector connector Machine connector 7 Pins Motor connector Solenoid-type presser lifter connector 1663M 5-3. Solenoid-type presser lifter (-9[][], Option) Studs [2 pcs] Presser lifter solenoid assy Bolts [3 pcs] Shoulder screw Presser foot lifting rod...
  • Page 25: Covers And Operation Panel

    5. DISASSEMBLY 5-5. Covers and operation panel 1666M Bobbin winder Screws [4 pcs] tension assy Arm cover Set screw [Loosen] Screws [2 pcs: Loosen] Cords [2 pcs] <DD7100> ear cover Screws [6 pcs] Screw Thread take-up cover Set screws [2 pcs: Loosen] Panel support Face plate brackets [2 pcs]...
  • Page 26: Tension Release Wire, Ground Wire And Thread Trimmer Solenoid

    5. DISASSEMBLY 5-6. Tension release wire, ground wire and thread trimmer solenoid 1668M Screw [2 pcs: Loosen] Screw [Loosen] Set screw [Loosen] Tension release wire Nuts [2 pcs] Screw Ground wire Thread trimmer solenoid [DD7100A,710A only] 5 Screw Thread trimmer cam lever shaft (Pull out) Retaining ring E Washer...
  • Page 27: Wick Holder And Oil Tube (Thread Take-Up Lever)

    5. DISASSEMBLY 5-7. Wick holder and oil tube (Thread take-up lever) Screw [Loosen] Oil tube Wick [Untie the knot] [Remove from underneath machine head] Screws [2 pcs] Wick holder 1672M 1673M 5-8. Oil tank, Bed under cover and sub tank 1674M <DD7100A, 710A>...
  • Page 28: Quick Reverse Solenoid

    5. DISASSEMBLY 1676M <DD7100> Felt Screw [Loosen] Bed under cover Oil gauge guide Oil tubes Oil tank 1675M Screws [2 pcs] -3[][] • -4[][] Lubricating oil Lubricating Screw 1) Place a dish under the lubricating oil outlet, and then remove the screw and drain the lubricating oil.
  • Page 29: Needle, Presser Hoot And Reverse Actuator Assy

    5. DISASSEMBLY 5-10. Needle, presser hoot and reverse actuator assy <Presser foot with integrated finger guard> 1678M Screw Set screw Reverse actuator assy Finger guard eedle Screws [2 pcs] Presser hoot 1679M 5-11. Thread tension mechanism Set screw [Loosen] Pre-tension assy Arm thread guide Screw Thread tension bracket assy...
  • Page 30: Bobbin Case, Rotary Hook And Thread Trimming Mechanism

    5. DISASSEMBLY 5-13. Bobbin case, rotary hook and thread trimming mechanism 1682M Screw Lower thread finger Fixed knife Washer Screw Bobbin case holder position bracket Screw Screw [Loosen] 21 Forked shaft 22 Collar Spring [Remove from stud] Movable knife holder assy Shoulder screw Spring [Remove] Knife holder presser plate...
  • Page 31: Presser Foot Mechanism

    5. DISASSEMBLY 5-16. Presser foot mechanism 1686M Adjusting screw Spring guide Spring Washer Thread guide Bolt Presser bar [Pull upward] Guide bracket Screw Wick Set screw [Loosen] Shaft [Slide to the right] Spring Washer Retaining ring E Shaft [Pull toward the outside] Tension release plate Retaining ring E 1688M...
  • Page 32: Needle Bar And Thread Take-Up Mechanism25

    5. DISASSEMBLY 5-18. Needle bar and thread take-up mechanism Rubber cap Rubber cap Set screws [2 pcs: Loosen] Set screw [Loosen] Set screws [3 pcs: Loosen] Thread Needle bar bush U take-up assy Crank Needle bar clamp Screw [Loosen] Needle bar Slide block 1691M 5-19.
  • Page 33: Timing Belt

    5. DISASSEMBLY 5-20. Timing belt Flange [DD7100 only] [DD7100 only] Screws [3 pcs: DD7100 only] Timing belt Timing belt [Remove from timing pulley D] 1696M [Remove from the arm] Note; For the DD7100A and 710A, the fan and flange do not need to be removed. 1695M 5-21.
  • Page 34: Lower Shaft, Lower Shaft Gear And Feed Regulator Set

    5. DISASSEMBLY 5-22. Lower shaft, lower shaft gear and feed regulator set Lower shaft [Pull out] <DD7100> Set screw 2 pcs: Loosen Set screw 4 pcs: Loosen 1699M Lower shaft gear Spacer [2 pcs] Set screw Set screw [2 pcs] 2 pcs: Loosen Set screw 2 pcs: Loosen]...
  • Page 35: Stitch Length Dial

    5. DISASSEMBLY 5-24. Stitch length dial 1701M Spring Stitch length dial [Turn counterclockwise all the way] Positioning pin Lock lever [Unlock: DD7100A, 710A only] Positioning pin [Push with a screwdriver or similar] Stitch length dial Stopper [Turn counterclockwise [Turn the stitch length dial counterclockwise again so that and remove] the stopper goes past the positioning pin] 1703M...
  • Page 36: Assembly

    Keep the oil out of the reach of children. Use only the proper replacement parts as If the power switch needs to be left on when specified by Brother. carrying out some adjustment, be extremely careful to observe all safety precautions.
  • Page 37 6. ASSEMBLY 4. Turn the stitch length dial (6) clockwise all the way. 5. Push the positioning pin (5) with a screwdriver or similar, and then turn the stitch length dial (6) clockwise again so that the stopper (7) passes to the right of the positioning pin (5).
  • Page 38: Rotary Hook Shaft, Thread Trimmer Cam And Gear

    6. ASSEMBLY 6-2. Rotary hook shaft, thread trimmer cam and gear 1. Insert the rotary hook shaft (1) into the arm so that the screw stops are at the right, and then place the thread trimmer cam (2) onto the rotary hook shaft (1) so that it faces as shown in the illustration.
  • Page 39: Lower Shaft, Lower Shaft Gear And Feed Regulator Set

    6. ASSEMBLY 6-4. Lower shaft, lower shaft gear and feed regulator set 1. Hold the lower shaft (1) so that it faces as shown in the illustration, insert it into the arm, and pass it trough the <DD7100> lower shaft gear (2) and the level feed eccentric wheel (3) of the feed regulator assembly inside the gear box.
  • Page 40 6. ASSEMBLY 9. Push back the feed regulator (13) as shown in the 1719M illustration, set so that the lower set screw (14) is facing toward the front, align it with the screw stop of the stud arm (11) and then tighten the set screw (14). (13) * Tighten the set screw (14) so that the stud arm (11) and joint (12) turn smoothly with no play.
  • Page 41: Timing Belt, Motor And Pulley

    6. ASSEMBLY 15. Align the lower set screw (22) and the set screw (7), then align the lower set screw (22) with the screw stop of the lower shaft (1) and tighten the set screw (22). At (23) this time, make sure that the movement of the feed regulator (13) does not become stiffer.
  • Page 42 6. ASSEMBLY 5. Tighten the two motor-side screws (12) of the joint. * At this time, align the screw stop of the rotor (13) Screw stops (13) with the upper set screw (12). (12) 1726M 6. Set the rotor (13) so that the screw stop is facing upward, and then install the pulley (14).
  • Page 43: Knee Lifter Lever Mechanism

    6. ASSEMBLY 6-6. Knee lifter lever mechanism 1. Move the knee lifter connecting rod D (1) as far to the left as possible, and then insert knee lifter lever D (2) into the arm bed. 2. Insert lever shaft D (3) into knee lifter lever D (2) from underneath, and then attach retaining ring E (4).
  • Page 44 6. ASSEMBLY 3. Set the thread take-up crank (5) so that line (A) is at a 1734M right angle to line (B) on the crank (2), and then while pushing the crank (2), tighten the set screw (6). (At this time, align the screw stop of the crank (2) with the set screw (6) when tightening it.) Approx.
  • Page 45 6. ASSEMBLY 8. Insert the needle bar (9) into the arm from above. 9. Tap needle bar bush U (10) into the arm so that the hole (C) is facing toward the pulley. * Tap in needle bar bush U (10) while checking that the needle bar (9) can move up and down (10) smoothly.
  • Page 46: Presser Foot Mechanism

    6. ASSEMBLY 6-8. Presser foot mechanism 1. Insert the shaft (1) into the arm. 2. Place the tension release plate (2) and the washer (3) onto the shaft (1). 3. Place the presser bar lifter lever (4) onto the shaft (1). 1741M 4.
  • Page 47: Feed Rocker Shaft

    6. ASSEMBLY 6-9. Feed rocker shaft 1. Place the washer (2) onto the feed rocker shaft (1), 1744M and then insert the feed rocker shaft (1) into the arm. * Insert the feed rocker shaft (1) so that the screw stop (A) of the feed rocker shaft (1) is facing upward and the oil tube hole (B) is facing downward.
  • Page 48: 6-11.Feed Bar Mechanism

    6. ASSEMBLY 6-11. Feed bar mechanism 1. Install the feed dog (1) to the feed bracket assembly (2) with the two screws (3). 1748M 2. Place the feed bracket assembly (2) onto the feed (14) 1749M rocker shaft (4). 3. Insert the wick (5) into the hole in the feed rocker shaft (4), and then insert the oil cap (6).
  • Page 49: 6-12.Sub Tank, Wick Holder And Wick

    6. ASSEMBLY 6-12.Sub tank, wick holder and wick <DD7100A, 710A> <DD7100A, 710A> 1. Install the sub tank (1) to the arm bed with the two screws with washer (2). * Be careful not to bend the oil gauge (3) at this time. 2.
  • Page 50: 6-13.Thread Tension Mechanism

    6. ASSEMBLY 7. Install the wick holder (8) to the arm with the two screws (9). 8. Tie together the wick that is coming out from the wick holder (8) and the wick that is coming out from the thread take-up support shaft (5). 9.
  • Page 51: 6-14.Oil (Feed Rocker Shaft)

    6. ASSEMBLY 6-14. Oil (Feed rocker shaft) 1. Secure the end of the wick in the oil tube (1) using a clip (2) or similar as shown in the illustration. (This is to prevent the wick from being pulled into the oil tube.) 2.
  • Page 52: Adjusting The Needle And Feed Mechanism Timing

    6. ASSEMBLY 8. Place the spring (13) onto the bush (14) so that it faces as shown in the illustration. (14) 9. Place the thread trimmer lever (15) onto the bush (14). (13) (15) * It will be easier to do this if you insert a screwdriver or similar into the gap.
  • Page 53: Installing The Movable Knife And Fixed Knife

    6. ASSEMBLY 1. Install the needle (3) to the needle bar with the screw 1765M 1766M (4). 2. Tilt back the machine head. 3. Loosen the two set screws (5) [four set screws for the DD7100]. Timing pulley D 4. Turn the feed lifting eccentric wheel (6) toward you so that the feed dog (1) moves down from its highest position until it is level with the top of the needle plate (2).
  • Page 54: Adjusting The Thread Trimming Timing

    6. ASSEMBLY 6-15-4. Adjusting the thread trimming timing Remove the fed dog. Needle bar lowest position Raised 5 mm Thread trimmer cam position adjustment 1. Turn the pulley to raise the needle bar 5 mm from its lowest position (reference line (a) position) so that reference line (b) is aligned with the bottom of the Reference line (b) Reference line (a)
  • Page 55: 6-16.Rotary Hook And Bobbin Case Holder Position Bracket

    6. ASSEMBLY 6-16. Rotary hook and bobbin case holder position bracket 1. Remove the feed dog. 2. Tilt back the machine head. 3. Place the high-speed rotary hook (2) onto the rotary hook shaft (1), and provisionally secure it with the three set screws (3).
  • Page 56: 6-17.Ruler Plate And Needle Plate

    6. ASSEMBLY 6-17. Ruler plate and needle plate 1. Remove the needle for safety while working. 2. Install the ruler plate (1) to the bed with the screw (2). 3. Install the feed dog (3) to the feed bar (4) with the two screws (5).
  • Page 57: Adjusting The Presser Foot Height

    6. ASSEMBLY 6-18-1. Adjusting the presser foot height The standard height for the presser foot (1) is 6 mm when the presser foot (1) is raised by the presser bar lifter (2). 1. Raise the presser foot (1) using the presser bar lifter (2).
  • Page 58: 6-19.Tension Release Wire

    6. ASSEMBLY 6-19. Tension release wire 1. Insert the terminal (2) end of the tension release wire 1785M (1) through the top of the arm, and attach it to the tension release plate (3). 2. Pass the other end of the tension release wire (1) through the arm as shown in the illustration.
  • Page 59: 6-20.Quick Reverse Solenoid

    6. ASSEMBLY 6-20. Quick reverse solenoid 1. Pass the cord (2) of the quick reverse solenoid (1) under the bed. 2. Install the quick reverse solenoid (1) to the arm with the three screws (4) so that the plunger pin (3) fits into the groove (A) in the solenoid lever.
  • Page 60: 6-21.Bed Under Cover (Gear Box)

    50 ml.) * Use only the lubricating oil (Nisseki Mitsubishi Sewing Lube 10N; VG10) specified by Brother. * Do not add more than the specified volume of lubricating oil.
  • Page 61: 6-22.Oil Tank

    6. ASSEMBLY 6-22. Oil tank <DD7100A, 710A> 1. Install the oil tank (1) to the bed with the two screws (2). (11) 2. Place the tube clip (4) onto the oil tube (3). (10) 3. Insert the oil tube (3) into the sub tank (5), and clamp it with the tube clip (4).
  • Page 62: 6-23.Tension Release Wire

    6. ASSEMBLY 6-23. Tension release wire 1. With the holder (2) installed to the tension release wire 1795M (1), pass the tension release wire (1) around the wire holder (3) and install it to the solenoid lever (5) with the two nuts (4).
  • Page 63: 6-26.Face Plate And Thread Take-Up Cover

    6. ASSEMBLY 4. Pass the cord (2) of the operation panel (1) under the arm as shown in the illustration. 1799M 6-26. Face plate and thread take-up cover 1. Install the face plate (1) to the arm with the three screws (2).
  • Page 64: 6-27.Safety Switch

    6. ASSEMBLY 6-27. Safety switch 1. Tilt back the machine head. 2. Install the safety switch (1) to the bed with the washer (2) and screw (3). 1802M 6-28. Arm cover, rear cover and bobbin winder tension assembly 1. Install the arm cover (1) to the arm with the four screws (2).
  • Page 65: 6-30.Connectors

    6. ASSEMBLY 6-30. Connectors 1. Insert the pins for the solenoid cords and the safety 1804M switch cord into the sewing machine 14P connector (1). • Match the numbers on the sewing machine 14P connector (1) with the numbers (tube marks) (2) on each pin.
  • Page 66: 6-31.Lubrication

    6. ASSEMBLY 6-31. Lubrication Use only the lubricating oil (Nisseki Mitsubishi Sewing Lube 10N; VG10) specified by Brother. <DD7100A, 710A> 1. Pour 130 ml of lubricating oil from the accessory oil bottle (2) in through the oil filler hole (1).
  • Page 67: 6-32.Bed Cover And Knee Lifter Lever

    6. ASSEMBLY 6-32. Bed cover and knee lifter lever 1. Install the bed cover (1) to the bed. 2. For sub-classes -30[], -31[], -40[] and -41[], push the knee lifter lever (2) onto the knee lifter shaft (3). (DD7100A,710A) (DD7100) 1809M SL-710A...
  • Page 68: 6-33.Test Operation

    6. ASSEMBLY 6-33. Test operation 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. For machines with a lower thread detector, set the lower thread remainder limit before carrying out test operation.
  • Page 69: 6-34.Adjusting The Safety Switch Position

    6. ASSEMBLY 6-34. Adjusting the safety switch position The safety switch (1) is normally installed as shown in 1810M figure (A). However, if the processing method used for the table leaves too much space between the machine head and the table hole, it may adversely affect the operation of the safety switch (1).
  • Page 70: Adjustments

    Ask your Brother dealer or a qualified electrician to result in injury. carry out any maintenance and inspection of the When carrying out inspection, adjustment and electrical system.
  • Page 71: Adjusting Arm Thread Guide R

    7. ADJUSTMENTS 7-2. Adjusting arm thread guide R The standard position of arm thread guide R (1) is the position where the screw (2) is in the center of the adjustable range for arm thread guide R. (1). Becomes greater Becomes less * To adjust the position, loosen the screw (2) and then move arm thread guide R (1).
  • Page 72: Adjusting Of The Feed Dog Height

    7. ADJUSTMENTS 7-4. Adjusting of the feed dog height The standard height of the feed dog (1) when it is at its <-[][]1, -[][]3> maximum height above the top of the needle plate is 0.8 0.8 mm mm for -[][]1/[][]3 models, and 1.2 mm for -[][]5 models. <-[][]5>...
  • Page 73: Adjusting The Feed Dog Angle

    7. ADJUSTMENTS 7-5. Adjusting the feed dog angle The standard angle for the feed dog (1) when it is at its highest position above the needle plate is when the “ ” mark (or V groove) on the shaft (2) is aligned with the feed rocker bracket arm (3) and the feed dog (1) is parallel to the needle plate.
  • Page 74: Adjusting The Needle Bar Height

    7. ADJUSTMENTS 7-6. Adjusting the needle bar height Reference line (a), which is the second line from the 0924M bottom of the needle bar (1)(fourth line from the bottom when using a DA X 1 needle) should be aligned with the lower edge of the needle bar bush D (2) as shown in the illustration when the needle bar (1) is at its lowest position.
  • Page 75: Adjusting The Needle And Rotary Hook Timing

    7. ADJUSTMENTS 7-8. Adjusting the needle and rotary hook timing The tip of the rotary hook (3) should be aligned with the 0928M 0929M center of the needle (4) when the needle bar (1) moves up from its lowest position to the position where reference 0 - 0.5 mm line (b), which is the line at the bottom of the needle bar (1) (third line from the bottom when using a DA X 1...
  • Page 76: Quick Reverse Mechanism

    7. ADJUSTMENTS 7-9. Quick reverse mechanism 1. Turn the stitch length dial to the maximum setting. 2. Remove the rear cover. 3. Tilt back the machine head. 4. Check that the position of the solenoid lever screw (1) can be verified when the machine head is restored to its normal position.
  • Page 77: 7-11.Synchronizer Adjustment

    7. ADJUSTMENTS 7-11. Synchronizer Adjustment The synchronizer uses a single element to detect the 0931M needle up stop position. The needle down single is fixed. Checking method Needle down position 1. Turn on the power switch. 2. Stop the machine with the needle in the needle down position.
  • Page 78: 7-12.Adjusting The Tension Release Wire

    7. ADJUSTMENTS 7-12. Adjusting the tension release wire If the tension discs stay open or if the upper thread pulls 1824M Open out of the needle after thread trimming, carry out the following adjustments. 2 - 3 mm * Lower the presser foot when making these Opening...
  • Page 79: 7-13.Adjusting The Treadle

    7. ADJUSTMENTS 7-13. Adjusting the treadle Adjusting the treadle pressure 0939M 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 80: 7-14.Adjusting The Rotary Hook Lubrication Amount

    7. ADJUSTMENTS 7-14. 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 81 7. ADJUSTMENTS When changing from the normal rotary hook to the rotary hook RP (lubrication-free rotary hook) 1. While referring to the instruction manual, replace the 0937M rotary hook RP and the cap screw. 2. Tighten the lubrication adjustment screw (3) as far as it will go, and then turn it back the other way about three full turns.
  • Page 82: Control System

    8. CONTROL SYSTEM 8. CONTROL SYSTEM 1825M Turn on the power switch (1). A. When the treadle is depressed 1. When the treadle (2) is depressed, a voltage corresponding to the amount of treadle depression is transmitted by the treadle unit (3) to the control box (4). 2.
  • Page 83: Removing And Installing The Control Box

    9. REMOVING AND INSTALLING THE CONTROL BOX 9. REMOVING AND INSTALLING THE CONTROL BOX DANGER Wait at least 10 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 84: Control Box And Motor Rating Plate

    10. CONTROL BOX AND MOTOR RATING PLATE 10. CONTROL BOX AND MOTOR RATING PLATE Control box • Check the phase, voltage and type for the control box. • Some specifications are identical for both single- and three-phase. Model MD-721:DD7100/Single-phase MD-722: DD7100A/Single-phase MD-7220:SL-710A/Single-phase MD-731:DD7100/Three-phase MD-732: DD7100A/Three-phase...
  • Page 85 Serial No. NO. G 0 1 A 11111 Design revision symbol (A, B, C...) Year of manufacture (last two digits of year) Month of manufacture (A - M) DD7100A DD7100 brother brother MD720A MD710A NO. G01A11111 NO. G97D11111 SL-710A brother M-72A NO.
  • Page 86: Control Circuit Board

    11. CONTROL CIRCUIT BOARD 11. CONTROL CIRCUIT BOARD DANGER Wait at least 10 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 87 11. CONTROL CIRCUIT BOARD Name Function Connectors Operation panel connector Connect to sewing machine connectors. Synchronizer connector (10) Lower thread detector connector (11) Sewing machine connector (12) Solenoid-type presser lifter connector Coupler connector Connect to power supply circuit board connectors. Relay connector Treadle connector Connect to treadle unit connector.
  • Page 88: Function Setting Methods

    12. FUNCTION SETTING METHODS 12. FUNCTION SETTING METHODS 12-1. DIP switch functions DANGER Wait at least 10 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 89: 12-2.Parameter Setting Flowchart

    12. FUNCTION SETTING METHODS 12-2. Parameter setting flowchart Start • Set memory switch 01 to ON. *1 • Turn off all LEDs. For the B-100 operation panel, select pattern 1. • Leave the machine stopped after thread trimming. • Press the thread trimming and AUTO keys.
  • Page 90: 12-3.Parameters

    12. FUNCTION SETTING METHODS 12-3. Parameters The parameter numbers appear on the panel. Parameter No.10 - 33 Parameter No. Default value Data value setting range Function Time delay from the time the machine starts to operate 15 (150 ms) 00 - 25 [X10] (0 - 250 ms) with the automatic presser foot raised to the time the moter operates.
  • Page 91 12. FUNCTION SETTING METHODS Parameter No.P0 - S5 Parameter Default value Data value setting range Function 00 (0 mm) -07 - 07 [X0.25] Thread trimmer operating point of depression stroke (-1.75 - 1.75 mm) -01 (-0.25 mm) -05 - 05 [X0.25] Back automatic presser lifter operating point of (-1.25 - 1.25 mm) depression stroke...
  • Page 92 12. FUNCTION SETTING METHODS <Parameter time setting> “T** ” in the diagram (where “**” is a two-digit number) corresponds to the various parameter numbers. Depressed forward Depressed backward Needle down signal Needle up signal Thread trimming (with no lower thread) Thread wiping Lower thread detector...
  • Page 93: 12-4.Memory Switch Setting Flowchart

    12. FUNCTION SETTING METHODS 12-4. Memory switch setting flowchart Start • Leave the machine stopped after thread trimming • Turn off all LEDs (except for the LED of the needle up/down stop key). (For the B-100 operation panel, select pattern 1.) •...
  • Page 94: 12-5.Memory Switches

    12. FUNCTION SETTING METHODS 12-5. Memory switches Memory switches 01 - 08 Parameter setting can be changed. Parameter setting Parameter setting change is prohibited. Forward step is possible during backward step (for thread trimming). Interlocking along with forward step Forward step is impossible during backward step (for thread trimming).
  • Page 95 12. FUNCTION SETTING METHODS Memory switches 21 - 28 Start backtacking is performed in the order of lengths A, B, A, then B. Double start backtacking Start backtacking is performed in the order of lengths A and B. End backtacking is performed in the order of lengths C, D, C, and D (B, A, B, and A on the B-20 operation panel).
  • Page 96 12. FUNCTION SETTING METHODS Memory switches 41 - 48 Foot pedal can be used after lower thread alarm. Mode after lower thread alarm After lower thread alarm, the foot pedal operation is deactivated until the cancel key is pressed. Rotary hook used with the lower 1.7-time rotary hook thread detector Standard rotary hook...
  • Page 97: Treadle Unit Assembly

    13. TREADLE UNIT ASSEMBLY 13. TREADLE UNIT ASSEMBLY 13-1.Types • Two different types are available: a type that controls the automatic presser lifter, and a type does not control the automatic presser lifter. • The two specifications are changed over by (A) changing the attachment position of the spring (1) inside the treadle unit, and (B) resetting the depression stroke signal.
  • Page 98: 13-2.Standard Setting Values

    13. TREADLE UNIT ASSEMBLY 13-2.Standard setting values Parameter Symbol Specification Treadle unit G Treadle unit H (diagram Operation Does not control automatic Controls automatic presser lifter below) presser lifter Spring position setting forward/back step Forward/back 1st step modulation modulation (Figure (Figure [b] on previous page) previous page) Function...
  • Page 99: 13-3.Setting Method For Standard Depression Strokes

    13. TREADLE UNIT ASSEMBLY 13-3. Setting method for standard depression strokes CAUTION If the power switch needs to be left on when carrying out some adjustment, be extremely careful to observe all safety precautions. When the specifications of the treadle unit are changed or if the treadle unit or control circuit board are replaced, it will be necessary to make new settings according to the procedure described below.
  • Page 100 13. TREADLE UNIT ASSEMBLY 2) Memorizing the maximum forward position • Carry out the following procedure while pressing the treadle forward as far as it will go. 0844M 1. Turn the PVR so that “45” appears in columns A and B (4) of the display window.
  • Page 101 13. TREADLE UNIT ASSEMBLY 4) Memorizing the maximum backward position • Carry out the following procedure while pressing the treadle backward as far as it will go. 1850M 1. Check that “rr” is flashing in columns A and B (4) of the display window.
  • Page 102 13. TREADLE UNIT ASSEMBLY 6) Memorizing the modulation position when pressing the treadle backward Press gently • Press the treadle backward until the depression force suddenly becomes heavier, and hold the pedal in that position while carrying out the following procedure. (For treadle unit H) •...
  • Page 103: Standing Operation Pedal

    14. STANDING OPERATION PEDAL 14. STANDING OPERATION PEDAL Some sub-classes are not equipped with <With foot plug set> <Without foot plug set> a foot plug set. In such cases, install the foot plug set (J02953-001) by the following procedure. Foot plug 1861M 1862M 14-1.
  • Page 104: 14-2.Connectors

    14. STANDING OPERATION PEDAL 14-2. Connectors At control box Standing operation pedal 9P connector DC+8 V High-speed switch Thread trimmer switch Spare Low-speed switch Presser foot switch Variable speed input Ground 1866M At pedal <Note> Connector types Manufacturer Connector No. Connector terminal MOLEX 1292 P...
  • Page 105: Puller

    15. Puller (commercially available) 15. Puller (commercially available) DANGER Wait at least 10 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 106: Auto Bobbin Changer

    16. AUTO BOBBIN CHANGER 16. AUTO BOBBIN CHANGER DANGER Wait at least 10 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 107: Speed Setting Methods

    17. SPEED SETTING METHODS 17. SPEED SETTING METHODS 17-1. Types of speed settings Type of speed Minimum setting Speed setting range Initial setting Signal Speed unit Low speed 150 - 300 Thread trimming speed 150 - Low speed Slow speed Low speed - 1000 Start backtacking limit LI (*1)
  • Page 108: 17-3.Checking The Speed Settings

    17. SPEED SETTING METHODS 6. Press the sewing speed key (5). 7. The "t" (Thread trimming speed) symbol will appear in LED display AB (4). 1879M 8. In this way, the symbol and the corresponding speed LED display will appear in the order given in the "Types of speed settings"...
  • Page 109: Clearing The Memory Data

    18. CLEARING THE MEMORY DATA 18. CLEARING THE MEMORY DATA Types of data that are cleared Clearing the memory data returns all of the following data items to the factory default settings. • Panel settings • Memory switch settings • Parameter settings •...
  • Page 110: Checking The Motor And Power Supply

    19. CHECKING THE MOTOR AND POWER SUPPLY 19. CHECKING THE MOTOR AND POWER SUPPLY CAUTION Turn off the power and disconnect the power plug from the wall outlet before carrying out these operations, otherwise the sewing machine may operate if the treadle is pressed by mistake, and injury may result. If the power switch needs to be left on when carrying out some adjustment, be extremely careful to observe all safety precautions.
  • Page 111: Checking The Solenoids

    20. CHECKING THE SOLENOIDS 20. CHECKING THE SOLENOIDS DANGER Wait at least 10 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 112: Wiring Diagrams

    21. WIRING DIAGRAMS 1889M 21. WIRING DIAGRAMS 21-1. Control circuit board assembly (1/6) SL-710A...
  • Page 113 21. WIRING DIAGRAMS 1934M Control circuit board assembly (2/6) SL-710A...
  • Page 114 21. WIRING DIAGRAMS 1890M Control circuit board assembly (3/6) SL-710A...
  • Page 115 21. WIRING DIAGRAMS 1891M Control circuit board assembly (4/6) SL-710A...
  • Page 116 21. WIRING DIAGRAMS 1892M Control circuit board assembly (5/6) SL-710A...
  • Page 117 21. WIRING DIAGRAMS 1893M Control circuit board assembly (6/6) SL-710A...
  • Page 118: 21-2.Power Supply Circuit Board Assembly (Dd7100A, 710A)

    21. WIRING DIAGRAMS 1894M 21-2. Power supply circuit board assembly (DD7100A, 710A) Power supply circuit board assembly (DD7100A, 710A) D-ADD1-110V (1/3) SL-710A...
  • Page 119 21. WIRING DIAGRAMS 1895M Power supply circuit board assembly (DD7100A, 710A) D-ADD1-110V (2/3) SL-710A...
  • Page 120 21. WIRING DIAGRAMS 1896M Power supply circuit board assembly (DD7100A, 710A) D-ADD1-110V (3/3) SL-710A...
  • Page 121 21. WIRING DIAGRAMS 1897M Power supply circuit board assembly (DD7100A, 710A) D-ADD1-240V (1/3) SL-710A...
  • Page 122 21. WIRING DIAGRAMS 1898M Power supply circuit board assembly (DD7100A, 710A) D-ADD1-240V (2/3) SL-710A...
  • Page 123 21. WIRING DIAGRAMS 1899M Power supply circuit board assembly (DD7100A, 710A) D-ADD1-240V (3/3) SL-710A...
  • Page 124 21. WIRING DIAGRAMS 1900M Power supply circuit board assembly (DD7100A, 710A) D-ADD3-220V (1/3) SL-710A...
  • Page 125 21. WIRING DIAGRAMS 1901M Power supply circuit board assembly (DD7100A, 710A) D-ADD3-220V (2/3) SL-710A...
  • Page 126 21. WIRING DIAGRAMS 1902M Power supply circuit board assembly (DD7100A, 710A) D-ADD3-220V (3/3) SL-710A...
  • Page 127: 21-3.Power Supply Circuit Board Assembly (Dd7100)

    21. WIRING DIAGRAMS 1903M 21-3. Power supply circuit board assembly (DD7100) Power supply circuit board assembly (DD7100) D-NDD1-120V (1/3) SL-710A...
  • Page 128 21. WIRING DIAGRAMS 1904M Power supply circuit board assembly (DD7100) D-NDD1-120V (2/3) SL-710A...
  • Page 129 21. WIRING DIAGRAMS 1905M Power supply circuit board assembly (DD7100) D-NDD1-120V (3/3) SL-710A...
  • Page 130 21. WIRING DIAGRAMS 1906M Power supply circuit board assembly (DD7100) D-NDD1-230V (1/3) SL-710A...
  • Page 131 21. WIRING DIAGRAMS 1907M Power supply circuit board assembly (DD7100) D-NDD1-230V (2/3) SL-710A...
  • Page 132 21. WIRING DIAGRAMS 1908M Power supply circuit board assembly (DD7100) D-NDD1-230V (3/3) SL-710A...
  • Page 133 21. WIRING DIAGRAMS 1909M Power supply circuit board assembly (DD7100) D-NDD3-240V (1/3) SL-710A...
  • Page 134 21. WIRING DIAGRAMS 1910M Power supply circuit board assembly (DD7100) D-NDD3-240V (2/3) SL-710A...
  • Page 135 21. WIRING DIAGRAMS 1911M Power supply circuit board assembly (DD7100) D-NDD3-240V (3/3) SL-710A...
  • Page 136: 21-4.Transformer

    21. WIRING DIAGRAMS 1912M 21-4. Transformer SL-710A...
  • Page 137: 21-5.Operation Panel B-40

    21. WIRING DIAGRAMS 1913M 21-5. Operation panel B-40 Operation panel B-40 (1/3) SL-710A...
  • Page 138 21. WIRING DIAGRAMS 1914M Operation panel B-40 (2/3) SL-710A...
  • Page 139 21. WIRING DIAGRAMS 1915M Operation panel B-40 (3/3) SL-710A...
  • Page 140: 21-6.Operation Panel B-100

    21. WIRING DIAGRAMS 1916M 21-6. Operation panel B-100 Operation panel B-100 (1/3) SL-710A...
  • Page 141 21. WIRING DIAGRAMS 1917M Operation panel B-100 (2/3) SL-710A...
  • Page 142 21. WIRING DIAGRAMS 1918M Operation panel B-100 (3/3) SL-710A...
  • Page 143: Troubleshooting

    • Please check the following points before calling for repairs or service. • If the following suggestions do not solve the problem, turn off the machine power supply and contact your nearest Brother service center. DANGER Wait at least 10 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 144 22. TROUBLESHOOTING Problem Possible cause Page • Are the thread tension spring tensions too strong? 5. Skipped stitches at sewing start Reduce the tension of the thread tension springs. • Is the thread tension spring operating range too large? Thread unravelling at sewing start Lower the position of the thread tension spring.
  • Page 145 • Is the bobbin turning smoothly? thread If the bobbin is not turning smoothly, replace the bobbin. • Is a bobbin other than the light-alloy bobbins specified by Brother being 0751M used? Use only bobbins which are specified by Brother.
  • Page 146 22. TROUBLESHOOTING Problem Possible cause Page • Is the resistance between terminals 3 - 4 of the sewing machine 13. Movable knife does not operate. connector normal? Measure the resistance between terminals 3 - 4 of the sewing machine connector with an ohmmeter. If the measured value is not normal, replace the thread trimmer solenoid.
  • Page 147 22. TROUBLESHOOTING Problem Possible cause Page • Is the power supply connector 18.Machine does operate when power is disconnected from the control turned on and treadle box? is pressed. Insert the connector securely. Instruction manual 1) Operating panel power indicator does 1002M illuminate.
  • Page 148 22. TROUBLESHOOTING Problem Possible cause Page • Is DIP switch 2 inside the control 22. Sewing machine starts operating before box set to OFF? presser foot is lowered Set DIP switch 2 to ON. (solenoid-type presser lifter specifications). 1921M • Is the solenoid-type presser lifter 23.
  • Page 149 22. TROUBLESHOOTING Problem Possible cause Page • Is memory switch No. 11 set to ON? The thread trimmer and thread wiper solenoids Set memory switch No. 11 to OFF. do not operate. • Are the solenoid resistances normal? If the resistances are not normal, replace the solenoids. •...
  • Page 150: 22-2.Error Code Displays

    22. TROUBLESHOOTING 22-2. Error code displays If an error code is flashing on the operation panel display Error code Possible cause Page • Is the bobbin changer power switch turned on? Turn on the bobbin changer power switch. 0996M • Is a standby signal still being input from the bobbin changer? Check the bobbin changer.
  • Page 151 22. TROUBLESHOOTING Error code Possible cause Page • Is the machine connector inside the control box disconnected? Instruction manual Insert the connector securely. • Is the machine head tilted back? Return the machine head to its normal position. 62, 104 Check the operation of the safety switch.
  • Page 152 22. TROUBLESHOOTING Error code Possible cause Page • Is the synchronizer connector inside the control box disconnected? Insert the connector securely. • Problem with synchronizer. Replace the motor. 0982M 1929M • Is detector pin (1) of the bobbin thread detector not retracted correctly? Retract the detector pin (1).
  • Page 153 SERVICE MANUAL 15-1, Naeshiro-cho, Mizuho-ku, Nagoya 467-8561, Japan. Phone: 81-52-824-2177 Printed in Japan 117-S11 I2010820H 2002.09. H (1)

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