Baby Lock BL-6800 Service Manual
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Baby Lock BL-6800 Service Manual

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6. 2001.

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Summary of Contents for Baby Lock BL-6800

  • Page 1 6. 2001.
  • Page 2 This service manual has been compiled for explaining repair procedures of the MODEL BL6800, BL6300. This was produced based on up-to-date product specifications at the time of issue, but there may have been changes of specifications for the purpose of improvements. Contact manufacturer or local sales company for information concerning such changes.

  • Page 3: Table Of Contents

    1. MECHANICAL CHART ..................2 2. POWER TRANSMISSION CHART ..............3 3. ELECTRONIC PARTS ARRANGEMENT CHART (BL6800 only) ....6 4. CONTROL SYSTEM BLOCK DIAGRAM (BL6800 only)........ 7 5. MOTOR UNIT CONTROL (BL6800 only)............7 6. OTHER ELECTRONIC COMPONENT FUNCTIONS (BL6800 only)....7...

  • Page 4: Mechanical Chart

    MECHANICAL CHART...

  • Page 5: Power Transmission Chart

    POWER TRANSMISSION CHART Generating mechanism of needle bar, thread take-up lever and zigzag movements Thread take- Thread take- Upper shaft Worm gear Timing pulley up lever up crank Needle bar crank rod Pattern cam Needle bar clamp Needle bar Zigzag connecting Needle bar Z finger Selecting cam...
  • Page 6 Mechanism of feed dog and rotary hook movement Feed pattern Horizontal feed cam Feed finger Worm gear Timing pulley pulley Forked Feed dog Feed regulator Driving belt connecting rod Timing belt Rotary hook Horizontal Horizontal Horizontal Feed carriage Motor assembly feed plate feed shaft feed arm...
  • Page 7 Automatic 1-step BH mechanism Feed control BHF finger 2-(B) cam (BH) assembly BH change BH change BHF finger BH stopper BH cam shaft assembly BH Iever 2-(A) BH foot...

  • Page 8: Electronic Parts Arrangement Chart (Bl6800 Only)

    ELECTRONIC PARTS ARRANGEMENT CHART (BL6800 only)

  • Page 9: Control System Block Diagram (Bl6800 Only)

    CONTROL SYSTEM BLOCK DIAGRAM (BL6800 only) Reset circuit Drive circuit Main motor Speed sensor Buzzer Needle position (NP) Foot controller CPU 32 pin Speed volume Start/stop switch Backstitch (BK) switch Bobbin winder switch MOTOR UNIT CONTROL (BL6800 only) The main motor for the sewing machine is required to smoothly change from low speed to high speed without any fluctuation due to load or power supply fluctuations or temperature change.
  • Page 10 1. DISASSEMBLING AND REASSEMBLING THE OUTER PARTS AND MAIN PARTS............9 2. LEAD WIRES ARRANGEMENT ..............29 3. MAIN PC BOARD ASSEMBLY REMOVEAL (BL6800 Only) ....... 30...
  • Page 11 DISASSEMBLING AND REASSEMBLING THE OUTER PARTS AND MAIN PARTS Disassembly procedure Remove the screws holding the face plate, then remove the face plate to the left. Remove the flat bed attachment by sliding it to the left. Remove the six screws holding the front cover (three on the rear, two on the bottom, one of the left), then lift up the front cover from the bottom side, open it forward, and remove it.
  • Page 12 (BL6800) Remove the three screws holding the PC board assembly on the rear of the sewing machine, remove the PC board assembly, and then remove the three wiring harness bands for the lamp cord. (BL6300) Remove the two screws holding the 3-pin socket folder assembly on the rear of the sewing machine, remove the 3-pin socket folder, and then remove the three wiring harness bands for the lamp cord.
  • Page 13 Remove the lock ring, remove the two screws holding the Zigzag dial assembly, and then remove the Zigzag dial assembly. Remove the two screws holding the thread tension assembly, then remove the thread tension assembly. 10. Remove the tension spring, two screws, lock ring, and the spring for forked connecting rod, remove the screws holding the Zigzag connecting rod adjustment nut, and remove the Zigzag connecting rod.
  • Page 14 15. Loosen the setscrew for the needle, then remove the needle. 16. Remove the screws holding the presser holder, then remove the presser holder and the presser foot. 17. Remove the tension spring from the needle bar block assembly. 18. Remove the screws holding the needle bar supporter stud holder assembly, then remove the needle bar supporter stud holder assembly.
  • Page 15 20. Loosen the BH change arm screw, remove the BH change shaft, remove the two screws holding the BH lever installation plate, and then remove the BH lever installation plate assembly. At the same time, remove the torsion spring. 21. Loosen the presser bar clamp screw, take out the presser bar, and then remove the presser bar clamp and presser spring.
  • Page 16 23. Remove the screw holding the thread take-up lever shaft fastening plate, then remove the thread take-up lever shaft. 24. Remove the left thread take-up lever screw, then remove the thread take-up lever. 25. Loosen the thread take-up crank set screw, then remove the needle bar crank and the needle bar crank rod. Disassembly Point 24.
  • Page 17 26. Remove the two needle plate screws, then remove the needle plate assembly and the inner rotary hook. 27. Remove the screw holding the inner rotary hook rotation prevention bracket, then remove the inner rotary hook rotation prevention bracket. 28. Remove the screw holding the inner rotary hook left retainer plate, then remove the inner rotary hook left retainer plate.
  • Page 18 31. Remove the lock ring for the horizontal feed arm shaft, loosen the horizontal feed arm set screw, then remove the horizontal feed arm shaft. 32. Remove the screw, then remove the feed dog slide guide assembly. Remove the screws holding the horizontal feed assembly center right and the horizontal feed assembly center left, remove the horizontal feed assembly center right and the horizontal feed assembly center left, then remove the horizontal feed shaft assembly.
  • Page 19 37. Remove the total of two screws securing the left and right metal pressers and remove the upper shaft assembly. 38. Remove the screw securing the fastening plate, then remove the feed regulator and feed regulator shaft. 39. Remove the two screws securing the BH stopper assembly, then remove the BH stopper assembly and spring.
  • Page 20 Assembly Procedure 46. Install the leg adjustment screws. 47. Install the three bottom leg rubber pads. 48. Pass the thread slack plate C and torsion spring onto the arm press-fit shaft, hang the torsion spring, then install with the CS lock ring. 49.
  • Page 21 54. Pass the upper shaft through the timing belt and install with the two metal pressers and two screws. Assembly Point 54. After installing the upper shaft, rotate the balance wheel by hand and check that it rotates freely. -19-...
  • Page 22 55. Pass the lower shaft section through the timing belt and secure with the eccentric metal presser (left side), the lower shaft metal presser (right side), and install with the two screws. Align the timing of the upper shaft and lower shaft. (See Adjustment Procedure 2.) 56.
  • Page 23 58. Insert the square block onto the forked connecting rod shaft and fit in the feed regulator square block groove. 59. Install the horizontal feed assembly center left with the screw. 60. Put the horizontal feed shaft push spring into the horizontal feed assembly center left and while compressing the spring, install the horizontal feed shaft assembly with the horizontal feed assembly center right and screw, then install the feed dog slide guide assembly with the screw.
  • Page 24 64. Hang the feed base tension spring. 65. Install the camber prevention plate with the two screws. 66. Put the inner rotary hook in place and install the inner rotary hook left retainer plate with the screw. (See Adjustment Procedure 9.) 67.
  • Page 25 69. Put the needle bar crank rod onto the needle bar crank shaft and install on the thread take-up crank with the set screw. Be careful about the flat surface the screw contacts with. 70. Install the thread take-up lever on the needle bar crank with the left screw. 71.
  • Page 26 72. Install the presser lifter shaft on the arm and install the presser lifter. 73. Pass the presser bar over the presser spring and presser bar clamp. Temporarily tighten the presser bar screw. (See Adjustment Procedure 13.) 74. Install the torsion spring on the BH lever installation plate, install the BH lever installation plate with the two screws, then install the BH change shaft, and fasten with the screw.
  • Page 27 75. Insert needle bar block assembly shaft into the arm hole, insert the needle bar holder shaft into the needle bar crank rod, then install the needle bar block assembly. Screw in the setscrew from the rear of the arm, position the needle bar block assembly forward and rear and tighten the lock nut.
  • Page 28 80. Align the feed bracket assembly fear section and install with the two tightening screws. (See Adjustment Procedure 18.) 81. Hang the feed regulator tension spring on the feed bracket assembly and feed regulator. 82. Install reverse sewing lever B on the arm and hang the tension spring on the reverse sewing lever B and feed bracket assembly.
  • Page 29 86. Install the motor (motor holder) with the two screws, and then hang the driving belt. (See Adjustment Procedure 3.) 87. Tighten the cord clamp and install with the screw. 88. (BL6800) Install the PC board assembly with the three screws, then fasten the lamp cord with the three bundling bands.
  • Page 30 89. Lower the presser lifter and install the rear cover and handle with the four screws (two on the front, one on the rear and one on the bottom). 90. Install the front cover with the six screws (three on the rear side, two on the bottom, and one on the left side).
  • Page 31 LEAD WIRES ARRANGEMENT (BL6800) (BL6300) -29-...
  • Page 32 MAIN PC BOARD ASSEMBLY REMOVAL (BL6800 Only) Removing the connector. For all connectors with more than two pins, gather the connector lead wires in a bundle and remove the connector without twisting the lead wires. Bobbin winder (BW) switch CN2 (BK) Backstitch (BK) switch CN3 (BW) CN1 (WB light)
  • Page 33 III. 1. SELECTING UNIT SECTION ADJUSTMENTS..........32 2. UPPER SHAFT AND LOWER SHAFT TIMING..........33 3. DRIVING BELT AND TIMING BELT TENSION..........34 4. NEEDLE DOWN POSITION ADJUSTMENT ..........35 5. NEEDLE FLOW....................36 6. LEFT STRAIGHT LINE SEWING NEEDLE DESCENT AND THE ZIGZAG MAXIMUM LEFT NEEDLE DESCENT ALIGNMENT ........

  • Page 34: Selecting Unit Section Adjustments

    SELECTING UNIT SECTION ADJUSTMENTS Super pattern adjustment (See Adjustment Procedure 19) Left baseline adjustment (See Adjustment Procedure 6) Feed adjustment (See Adjustment Procedure 20) BHF back feed (forward/reverse) (See Adjustment Procedure 22) BHF bar tack feed (See Adjustment Procedure 23) BH needle descent adjustment (See Adjustment Procedure 21) Z finger position &...

  • Page 35: Upper Shaft And Lower Shaft Timing

    UPPER SHAFT AND LOWER SHAFT TIMING Adjustment Standard The alignment mark for the upper shaft horizontal feed cam pulley and the alignment mark for the lower shaft timing pulley should be at the front of the sewing machine. (Turn the balance wheel forward.) Adjustment Procedure Remove the timing belt from the upper shaft horizontal feed cam pulley section and the tension pulley and the lower shaft timing pulley.

  • Page 36: Driving Belt And Timing Belt Tension

    DRIVING BELT AND TIMING BELT TENSION STANDARD There should the 4-6 mm slack in the driving belt when the driving belt upper shaft pulley and motor pulley center are pressed gently with a finger (Reference Figure 2N) with a force of approximately 200 g. There should be 3-4 mm slack in the timing belt when the timing belt upper shaft horizontal feed cam pulley and tension pulley center are pressed slightly strongly with a finger (Reference Figure 3N) with a force of approximately 300 g.

  • Page 37: Needle Down Position Adjustment

    NEEDLE DOWN POSITION ADJUSTMENT STANDARD The needle descent for zigzag sewing should be such that the needle descends evenly to the center of the needle hole in the needle plate. ADJUSTMENT Turn the selection dial, set the pattern display to zigzag and turn the Zigzag dial to the maximum. Turn the balance wheel, lower the needle and turn the Zigzag dial to 0.

  • Page 38: Needle Flow

    NEEDLE FLOW STANDARD For zigzag sewing, the distance from the needle plate upper surface to the tip of the needle (#14) when the needle bar starts oscillating movement should be 5.6±0.4 mm. Also, the distance from the needle plate top surface to the needle (#14) tip when the needle bar oscillating movement stops must be 7.8±0.4 mm.

  • Page 39: Left Straight Line Sewing Needle Descent And The Zigzag Maximum Left Needle Descent Alignment

    LEFT STRAIGHT LINE SEWING NEEDLE DESCENT AND THE ZIGZAG MAXIMUM LEFT NEEDLE DESCENT ALIGNMENT STANDARD The left straight line sewing needle descent and zigzag maximum left needle descent should match. ADJUSTMENT Move the feed drop slide to the right to put the feed dog in the down position. Lay paper under the presser foot.

  • Page 40: Timing Of Needle And Rotary Hook Assembly (Clearance Between The Needle And The Rotary Hook Point)

    TIMING OF NEEDLE AND ROTARY HOOK ASSEMBLY (CLEARANCE BETWEEN THE NEEDLE AND THE ROTARY HOOK POINT) STANDARD For left straight line sewing, the rotary hook assembly point and the needle outer edge should match when the needle rises 2.9-3.3 mm from bottom dead center. The clearance between the rotary hook assembly point and the routing surface of the needle (#14) at this time should be no greater than 0.15 mm on both left and right and the rotary hook assembly point should not touch the needle.

  • Page 41: Needle Bar Height

    NEEDLE BAR HEIGHT STANDARD For left straight line sewing, when the needle outer edge and rotary hook assembly point match, the distance from the needle hole top edge to the rotary hook assembly point lower edge should be 1.0-1.4 mm. ADJUSTMENT 1.

  • Page 42: Inner Rotary Hook Retainer Plate L Position

    INNER ROTARY HOOK RETAINER PLATE L POSITION STANDARD The clearance between the inner rotary hook retainer plate L and the rotary hook assembly top surface should be 0.4-0.6 mm. ADJUSTMENT Loosen the screw securing the inner rotary hook retainer plate L. Adjust the vertical position of the inner rotary hook retainer plate L and adjust so that the clearance between the inner rotary hook presser plate L and the rotary hook assembly top surface is 0.4-0.6 mm.

  • Page 43: Inner Rotary Hook Rotation Prevention Bracket Position

    INNER ROTARY HOOK ROTATION PREVENTION BRACKET POSITION STANDARD The hanging distance for the inner rotary hook rotation prevention bracket spring and the inner rotary hook projection section should be 1.6-1.8 mm. ADJUSTMENT Loosen the setscrew for the inner rotary hook rotation prevention bracket. Adjust the forward-back position of the inner rotary hook rotation prevention bracket so that the hanging difference for the inner rotary hook rotation prevention bracket spring and inner rotary hook projection section is 1.6-1.8 mm.

  • Page 44: Feed Dog Front-Rear And Left-Right Position

    FEED DOG FRONT-REAR AND LEFT-RIGHT POSITION STANDARD The left-right position should be such that when the upper shaft is rotated one rotation with the maximum feed distance, the feed dog does not touch the needle plate. (The clearance between the needle plate and the feed dog should be at least 0.1 mm.) The forward-reverse position should be such that there is a clearance of 0.3-0.8 mm between the feed dog and the needle plate at the feed start position (when the feed dog are the most forward) for the maximum feed...

  • Page 45: Feed Dog Height

    FEED DOG HEIGHT STANDARD The feed dog standard height is such that when the feed dog are top dead center, the feed dog center section extends 0.9-1.1 mm from the needle plate upper surface. ADJUSTMENT Turn the balance wheel to move the feed dog to top dead center. Loosen the screw securing the vertical feed finger.

  • Page 46: Presser Bar Height

    PRESSER BAR HEIGHT STANDARD The height of the presser bar should be such that when the presser lifter is raised (1st-stage lift state), the distance from the top surface of the needle plate to the bottom surface of the presser foot should be 6.0-6.5 mm. ADJUSTMENT Raise the presser lifter.

  • Page 47: Thread Tension Dial Tension

    THREAD TENSION DIAL TENSION STANDARD With the presser foot down and the thread tension dial set to position 4, when polyester thread (#60, green) is pulled slowly down with the tension gauge, the reading should be 0.33-0.38 N (33-38 gf). ADJUSTMENT 1.

  • Page 48: Selection Dial Outer Edge Play

    SELECTION DIAL OUTER EDGE PLAY STANDARD The selection dial outer edge play should be 0.5-2 mm. ADJUSTMENT Loosen the screw securing the presser plate. Rotate the selection dial bearing to adjust the play. Tighten the screw securing the presser plate. Adjustment Points Turning the selection dial bearing so that the alignment mark is up reduces play;...

  • Page 49: Pattern Display Selection Positioning

    PATTERN DISPLAY SELECTION POSITIONING STANDARD When the selection dial is selected, the appropriate pattern display should appear in the center of the pattern display window. ADJUSTMENT Turn the selection dial to zigzag sewing. Loosen the two screws securing the indication gear. Align the center of the square groove on the indication gear and the center of the unit base F hole.

  • Page 50: Z Finger Positioning

    Z FINGER POSITIONING STANDARD The Z finger should come to the center of the corresponding pattern cams. ADJUSTMENT Turn the selection dial and check the position of the Z finger relative to the cam. Turn the selection dial to zigzag sewing and loosen the two screws securing the indication gear. Move the selection cam left and right and align the Z finger and the pattern cam center.

  • Page 51: Feed Bracket Installation Position

    FEED BRACKET INSTALLATION POSITION STANDARD When the feed dial is set to 0, the feed dial gear and idle gear and feed cam alignment marks should match. ADJUSTMENT Turn the feed dial to the 0 position. Check that the feed dial gear alignment mark and idle gear alignment mark match. Check that the idle gear alignment mark and feed cam alignment mark match.

  • Page 52: Super Pattern (Triple Sewing)

    SUPER PATTERN (TRIPLE SEWING) STANDARD Be particularly careful, the pattern will break down unless the super pattern stitch length forward and reverse lengths are correctly adjusted. ADJUSTMENT Turn the selection dial to zigzag sewing, turn the Zigzag dial to the maximum, and set the feed dial to SS position.

  • Page 53: Feed Adjustment

    FEED ADJUSTMENT STANDARD When the feed dial is 2, the feed distance for left straight line sewing should be 1.8-2.2 mm for 10 pitch. ADJUSTMENT Turn the selection dial to straight line sewing, turn the Zigzag dial to maximum, and set the feed dial to 2. Loosen the adjustment screw nut.

  • Page 54: Bh Left Needle Descent And Zigzag Maximum Left Needle Descent Alignment

    BH LEFT NEEDLE DESCENT AND ZIGZAG MAXIMUM LEFT NEEDLE DESCENT ALIGNMENT STANDARD The difference between the BH left needle descent and the Zigzag maximum left needle descent must be 0.7 - 0.9 mm. ADJUSTMENT Move the feed drop slide to the right to put the feed dog in the down position. Lay paper under the presser foot.

  • Page 55: Button Hole Stitch Left Reverse Stitch And Right Forward Stitch Length

    BUTTON HOLE STITCH LEFT REVERSE STITCH AND RIGHT FORWARD STITCH LENGTH STANDARD When the feed dial is in the F position, the left reverse stitch and right forward stitch length must be the same. ADJUSTMENT Set the feed dial to F position. Check the difference between the left reverse stitch and right forward stitch length.

  • Page 56: Button Hole Stitch Bar Tack Feed Adjustment

    BUTTON HOLE STITCH BAR TACK FEED ADJUSTMENT STANDARD The button hole stitch bar tack feed distance should be no greater than 1 mm for 10 pitch. ADJUSTMENT Turn the selection dial to BH sewing and execute bar tack sewing. Loosen the bar tack adjustment screw nut. Adjust by turning the bar tack adjustment screw.

  • Page 57: Button Hole Stitch Button Hole Length

    BUTTON HOLE STITCH BUTTON HOLE LENGTH STANDARD When a button hole is sewn using a 20 mm button, the button hole length should be sewn 21-23 mm. The BH operation should be 0.5-1.1 N (50-110 gf) on the return side. ADJUSTMENT Loosen the BH change arm set screw.

  • Page 58: Thread Winding Adjustment

    THREAD WINDING ADJUSTMENT STANDARD The thread should be wound parallel to the bobbin and 75-85 percent of the outer diameter of the bobbin. ADJUSTMENT Wind the thread and check the status of the thread wound onto the bobbin. Slightly loosen the screw securing the lower thread winding thread guide. Move the lower thread winding thread guide up and down to adjust the bobbin winding.

  • Page 59: Forward And Reverse Stitch Length (Straight Line Stitch Length)

    FORWARD AND REVERSE STITCH LENGTH (STRAIGHT LINE STITCH LENGTH) STANDARD When the feed dial is to set to 2, there should be no difference between the stitch length for forward and reverse. ADJUSTMENT Turn the selection dial and the Zigzag dial to medium straight line sewing. Set the feed dial to 2.

  • Page 60: Needle Stop Positioning (Np) (Bl6800 Only)

    NEEDLE STOP POSITIONING (NP) (BL6800 Only) Standard When the sewing machine is stopped, the distance from the top of the needle (#14) to the top surface of the needle plate must be 11.9 - 14.7 mm. Adjustment Run the sewing machine, stop it with the SS button, then check the needle stop position (the distance from the top of the needle (#14) to the top surface of the needle plate).

  • Page 61: Backstitch (Bk) Switch Adjustment (Bl6800 Only)

    BACKSTITCH (BK) SWITCH ADJUSTMENT (BL6800 Only) STANDARD The backstitch switch must come ON for reverse sewing lever operation with a feed of F or more. When the feed is 3, the backstitch switch must not come ON in the reverse sewing lever play range (range in which the feed adjuster is not pressed).

  • Page 62: Needle Threader

    NEEDLE THREADER USING THE NEEDLE THREADER There are a wide variety of different needles and sewing machine threads available. The right ones should be selected in accordance with the sewing conditions. The accessory needle threader is designed to make threading of needles easier, but it cannot handle every single usage circumstance (combination of needle and thread that might occur.

  • Page 63: (Checking The Hook Position In The Horizontal Direction)

    NEEDLE THREADER (CHECKING THE HOOK POSITION IN THE HORIZONTAL DIRECTION) STANDARD Needle threading should be possible when the needle holder bottom surface and hook holder bottom surface height have been aligned. * Left-right direction relative to the needle hole The hook left-right direction reference position should be at the needle hole center. (The clearance between the hook and the left and right of the needle hole should be the same.) * Up-down direction relative to the needle hole The clearance between the hook and top end of the needle hole should be 0-0.1 mm.

  • Page 64: Needle Threader (Exchange)

    NEEDLE THREADER (EXCHANGE) HOW TO REPLACE NEEDLE THREADER Removes the two screws securing the hook. Install the new hook, then tighten the two screws securing the hook. If the threader hook does not enter the needle hole correctly, adjust the threader. (29. NEEDLE THREADER) Screws securing hook -62-...
  • Page 65 1. Machine skips stitches................. 64 2. Fabric does not feed..................64 3. Fabric does not feed straight ..............64 4. Upper thread breaks at start................ 64 5. Upper thread breaks during sewing ............64 6. Upper thread breaks during reverse sewing..........64 7.

  • Page 66: Machine Skips Stitches

    PROBLEM CAUSE CORRECTION Machine skips 1. Improper setting of the needle. 1. Set the needle correctly. stitches. 2. Bent or blunt needle. 2. Change the needle. 3. Improper threading. 3. Reset threading correctly. 4. Improper combination of needle/ thread/fabric. 4. Select correct combination of needle/ thread/fabric.

  • Page 67: Needle Breaks

    PROBLEM CAUSE CORRECTION 8. Needle breaks. 1. Touch pattern dial while needle is in the fabric. 1. Operate machine correctly. 2. Needle hits inner rotary hook. 2. Adjust the position of inner rotary hook stopper. * Refer to P.41. 3. Needle hits needle plate. 3.

  • Page 68: The Stitch Shown In The Pattern Indication Window Is Different From The One Being Sewn

    PROBLEM CAUSE CORRECTION 16.The stitch 1. Release volume is too small. 1. Adjust the release volume. shown in the * Refer to P.37. pattern 2. The indicate gear and pattern indicator plate are not 2. Adjust the pattern indicator. indication aligned correctly.
  • Page 69 Connector ...................... 68 Main PC board....................69 SS-VR board ....................70 HOW TO ADJUST ELECTRON ELEMENTS 1. When power is turned on, the lamp does not light up ......71 2. Main motor does not operate ..............71 3. Operation of main motor is not stable or maximum speed operation is not possible....................

  • Page 70: Connector

    Connector Bobbin winder (BW) switch CN2 (BK) Backstitch (BK) switch CN3 (BW) CN1 (WB light) CN4 (FC) Main PC board Motor Controller (FC) jack board WB light Sensor Power supply switch board Inlet Speed VR board Motor -68-...

  • Page 71: Main Pc Board

    Main PC board (BL6800 only) CN9 Motor CN8 Inlet (Power supply input) CN7 Power supply switch CN1 Lamp Reverse sewing switch CN6 SS-VR board Bobbin winder switch Foot controller jack Sensor board LJ1 FG Line -69-...

  • Page 72: Ss-Vr Board

    SS-VR board (BL6800 only) Speed volume Start/Stop switch 1 pin -70-...

  • Page 73: How To Adjust Electron Elements 1. When Power Is Turned On, The Lamp Does Not Light Up

    ∗ You must turn off the power and remove connectors from printed circuit boards before measuring resistance. PROBLEM CAUSE CORRECTION When power is 1. Plug in the AC cord. Is there 120 VAC across the 1. Replace the cord reel or turned on, the source connector? replace the main PC board...

  • Page 74: The Motor Starts, Then Stops Immediately

    The motor 1. Is the sensor PC board assembly installation normal? 1. Correct the installation. starts, then Is it floating loose or tilted? stops 2. Others 2. Replace the main PC board immediately. assembly. 5. Speed cannot 1. Is the transistor output normal? Is the voltage 1.

  • Page 75: During Thread Winding, The Motor Starts, But Stops Immediately

    PROBLEM CAUSE CORRECTION 8. During thread 1. When the motor stops about one second after 1. Replace the bobbin winder winding, the starting during thread winding switch assembly. motor starts, Is the bobbin winder switch normal? but stops Is the resistance between 1-2 on connector CN3 immediately.
  • Page 76 BL-6800 BL-6300 H1060208...

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Bl-6300

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