Brother LZ2-B855E Service Manual
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Brother LZ2-B855E Service Manual

Brother LZ2-B855E Service Manual

Electronic single needle zigzag lock stitcher electronic single needle zigzag lock stitcher with thread trimmer
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LZ2 - B855E
LZ2 - B856E
Please read this manual before making any adjustments.
ELECTRONIC SINGLE NEEDLE ZIGZAG LOCK STITCHER
ELECTRONIC SINGLE NEEDLE ZIGZAG LOCK STITCHER WITH THREAD TRIMMER
SERVICE MANUAL

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Summary of Contents for Brother LZ2-B855E

  • Page 1 LZ2 - B855E SERVICE MANUAL LZ2 - B856E Please read this manual before making any adjustments. ELECTRONIC SINGLE NEEDLE ZIGZAG LOCK STITCHER ELECTRONIC SINGLE NEEDLE ZIGZAG 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

    Furthermore, do not ex- cessively bend the cords or secure them too Contact your Brother dealer or a qualified electri- firmly with staples, otherwise there is the danger cian for any electrical work that may need to be that fire or electric shocks could occur.

  • Page 4: Maintenance And Inspection

    Ask your Brother dealer or a qualified electrician If using a work table which has casters, the cast- to carry out any maintenance and inspection of ers should be secured in such a way so that they the 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. Hazardous voltage...
  • Page 6 Oil pan 1113S 1114S 1115S 1116S • Automatic presser foot lifter (B856E-90 |, option) 1117S LZ2-B855E,B856E...

  • Page 7: Table Of Contents

    Adjusting the forward/back position of the needle bar ..........6-06 6-9. Adjusting the right/left position of the needle bar ............. 6-07 6-10. Adjusting the needle bar height ....6-08 6-11. Adjusting the needle and rotary hook timing ..............6-09 LZ2-B855E,B856E...

  • Page 8: Machine Specifications

    1. MACHINE SPECIFICATIONS 1. MACHINE SPECIFICATIONS BROTHER INDUSTRIES, LTD. BROTHER INDUSTRIES, LTD. BROTHER INDUSTRIES, LTD. LZ2-B855E-3 LZ2-B855E-0/BT LZ2-B856E-103 MADE IN JAPAN MADE IN JAPAN MADE IN JAPAN <with back tack/condense device *1> B856E Thread trimmer Solenoid Upper thread feeding device...

  • Page 9: Sewing Pattern Table

    1 to 99 stitches. (No. of stitches) Blind stitch (right) Sewing patterns created using the BAS-PC/300 (optional device) can Custom made pattern be sewn. ✻ (The pattern number is set in the columns marked with LZ2-B855E,B856E 2-01...

  • Page 10: Mechanical Descriptions

    3. Timing pulley U 7. Lower shaft gear 1. Pulley 6. Lower shaft 4. Timing belt 13. Rotary hook 10. Bevel gear 5. Timing pulley D 8. Driving gear 9. Driving shaft 12. Rotary hook shaft 1119S 11. Bevel gear 3-01 LZ2-B855E,B856E...

  • Page 11: Zigzag Mechanism

    When pulse motors are used for high-speed drive control, vibration inevitably occurs. This new mechanism uses a spring plate to absorb the inertial reaction force generated during high-speed operation quickly and efficiently. The new electronic zigzag mechanism allows sewing at high speed with no pattern distortion. LZ2-B855E,B856E 3-02...

  • Page 12: Presser Foot Mechanism

    1. Knee lifter 1098S <B856E-90[ ]> 3. Guide bracket 3. Knee lifter complying bar assy 2. Lifter lever 2. Knee lifter shaft 1. Presser foot lifter 1100S 1. Presser bar lifter 4. Presser bar 5. Presser foot 1099S 3-03 LZ2-B855E,B856E...

  • Page 13: Feed Mechanism

    8. Spring 6. Connecting rod 7. Feed regulator 1126S Connecting rod Feed rocker arm Side connecting rod The horizontal feed amount changes when the angle of the feed regulator is changed. Feed regulator 1127S LZ2-B855E,B856E 3-04...
  • Page 14 The angle of the feed regulator when the backtack lever is pressed down can be changed by adjusting the condense dial. When the condense dial is turned to the - (minus) side of the scale, the angle of the feed regulator becomes greater and reverse feeding is carried out. 1105S 3-05 LZ2-B855E,B856E...

  • Page 15: Lubrication

    Supply oil 1108S I6. Oil cap screw with hole I5. Felt I4. Oil valve I3. Rotary hook shaft M4. Adjusting screw I M2. Oil lip M5. Bed I7. Supply oil felt M3. Bush F I8. Oil wick felt 1129S LZ2-B855E,B856E 3-06...

  • Page 16: Thread Trimmer Mechanism (B856E)

    5. Driving rod plate 6. Main lever assy 7. Roller 11. Movable knife 1. Thread trimmer solenoid 2. Solenoid joint 10. Driving lever 9. Knife driving rod 3. Solenoid lever 4. Driving rod 1130S Clutch Fixed knife Spring Movable knife 1131S 3-07 LZ2-B855E,B856E...

  • Page 17: Tension Release Mechanism

    Tension release pin 6. Disc presser <Tension release of thread trimming (B856E)> 2. Link 3. Lever 1. Solenoid 5. Tension release connecting rod 4. Lever 7. Tension release stud 6. Tension release plate 8. Tension release pin 1111S LZ2-B855E,B856E 3-08...

  • Page 18: Thread Wiper Mechanism (B856E)

    1. Solenoid 2. Link 4. Base 5. Wire 1112S 3-9. Thread wiper mechanism (B856E) 1. Thread wiper solenoid 6. Spring 2. Thread wiper rod 3. Thread wiper connecting rod 4. Thread wiper crank 1132S 5. Thread wiper 3-09 LZ2-B855E,B856E...
  • Page 19 3. MECHANICAL DESCRIPTIONS LZ2-B855E,B856E 3-10...

  • Page 20: Disassembly

    Use only the proper replacement parts as specified Keep the oil out of the reach of children by Brother. Any problems in machine operation which result If any safety devices have been removed, be ab- from unauthorized modifications to the machine will not be covered by the warranty.

  • Page 21: Presser Mechanism

    2. Presser foot 1125S 4-3. Needle bar mechanism 1. Rubber cap 1066S 5. Needle bar 4. (Loosen) 3. Thread guide 7. Two set screws 8. Thread take-up lever shaft (Loosen) 6. Needle bar clamp 9. Needle bar connecting rod 1068S LZ2-B855E,B856E 4-02...

  • Page 22: Zigzag Mechanism

    9. Wick (Remove from the shaft of the needle bar bracket.) 7. (Loosen) Shaft of needle bar bracket 10. (3 pcs) 11. (Flat) 15. Needle bar bracket 12. Zigzag unit 13. Set screw (Loosen) 14. Pin F Wick 1083S 4-03 LZ2-B855E,B856E...

  • Page 23: Rotary Hook Mechanism

    11. Rotary hook 1069S 4-6. Feed mechanism Set screw collar 5. Felt (Pull) 2. Two set screws (Loosen) 6. Feed base assy 4. Feed rocker shaft (Slide right) 1. (Loosen) 3. Two set screws (Loosen) Feed rocker arm 1070S LZ2-B855E,B856E 4-04...

  • Page 24: Thread Trimmer Mechanism (B856E)

    5. Main lever assy 7. Thread trimmer solenoid Remove Washer 1. Shoulder screw 2. Knife driving rod 1. Shoulder screw 1084S <Knife unit> 1. (4 pcs) 2. Knife holder 3. Movable knife 4. Fixed knife 5. Knife bracket 1085S 4-05 LZ2-B855E,B856E...

  • Page 25: Thread Wiper Mechanism (B856E-40[ ], -90[ ])

    5. Two screws 6. Shoulder screw 8. Wiper bracket 2. Presser foot 1133S 10. Remove six screws 1134S 11. 12 pin connector 1136S No. 6 Black No. 5 White A special tool is needed to pull out the pins. 1135S LZ2-B855E,B856E 4-06...

  • Page 26: Panel

    1. Remove six screws 1134S 1137S 5. Cord holder (Remove the panel harness. ) 3. Cord bush (Remove the panel harness. ) 6. Two set screws (Loosen) Panel harness 7. Two panel support bracket 1138S 8. Panel 1139S 4-07 LZ2-B855E,B856E...
  • Page 27 4. DISASSEMBLY LZ2-B855E,B856E 4-08...

  • Page 28: Assembly

    Adjust the length of the knife driving rod so that the roller of the main lever moves smoothly in and out of the straight section A of the groove in the thread trimming cam. After making this assembly, you should also carry out the adjustment in "6-18. Adjusting the timing of the thread trim- ming" (page 6-15). 5-01 LZ2-B855E,B856E...

  • Page 29: Feed Mechanism

    7. Two set screws 8. Two set screws (*Temporarily tighten) Feed rocker arm 1070S * After adjusting the feed dog, tighten the two screws. Refer to "6-5. Adjusting the forward/back, right/left position of the feed dog" (page 6-03). LZ2-B855E,B856E 5-02...

  • Page 30: Zigzag Mechanism

    And carry out the adjustment in "6-8. Adjusting the forward/back position of the needle bar" (page 6-06). **** Adjustment of the home position carry out the adjustment in "6-9. Adjusting the right/left position of the needle bar" (Page 6-07). 15. Knee lifter bar 1082S 5-03 LZ2-B855E,B856E...

  • Page 31: Needle Bar Mechanism

    9. Rubber cap 5. Needle bar 6. *Screw (Temporarily tighten) Face to front 7. Thread guide 1066S 1073S * After adjusting the needle bar height, tighten the screw. Refer to "6-10. Adjusting the needle bar height" (page 6-08). LZ2-B855E,B856E 5-04...

  • Page 32: Rotary Hook Mechanism

    After "6-11. Adjusting the needle and rotary hook timing" (page 6-09), tighten the two set screws. After "6-12. Adjusting the hook stopper position" (page 6-09), tighten the screw. *** After "6-5. Adjusting the forward/back, right/left position of the feed dog" (page 6-03), tighten the two screws. 5-05 LZ2-B855E,B856E...

  • Page 33: Presser Mechanism

    13. (Adjust needle hole) 15. Adjustment screw 16. Adjustment nut 1079S Specification -[ ][ ]1 -[ ][ ]3 31 mm * 31 mm for export models (24.5 mm when using at 4,000 rpm or above) ((Japanese models is 23 mm)) LZ2-B855E,B856E 5-06...

  • Page 34: Panel

    Also 6. Cord bush make sure that it does not touch any moving parts such Install panel as the upper shaft and timing belt. harness. Panel harness 1138S 7. 4 pin connector 8. Tighten six screws 1134S 1137S 5-07 LZ2-B855E,B856E...

  • Page 35: Cover

    6. Flat screws (7 pcs) 12. Thread take-up 4. Face plate packing guard assy 5. Face plate 9. Thread take-up mounting plate 11. Flat screws (3 pcs) 8. Flat screw 13. (2 pcs) 7. Thread guide 10. Rotary thread take-up lever 1088S LZ2-B855E,B856E 5-08...

  • Page 36: Thread Wiper Mechanism (B856E-40[ ], -90[ ])

    7. Presser foot 1133S No. 6 Black No. 5 White 13. 12 pin 12. 12 pin connector connector 1136S 1135S 14. Tighten six screws 1134S 5-09 LZ2-B855E,B856E...
  • Page 37 5. ASSEMBLY LZ2-B855E,B856E 5-10...

  • Page 38: Adjustments

    Ask your Brother dealer or a qualified electrician sult in injury. • to carry out any maintenance and inspection of When carrying out inspection, adjustment and the electrical system.

  • Page 39: Adjusting The Presser Foot Height

    3. Loosen the screw w. 4. Turn the pin e to move the feed bar r up and down in 1.1mm order to adjust the height. 5. Securely tighten the screw w. <B856E> 1003S Highest position Standard Lowest position 0593M LZ2-B855E,B856E 6-02...

  • Page 40: Adjusting The Feed Dog Angle

    If adjustment is not possible, carry out the following ad- justment. <Adjusting the front and back clearances Y and the left and right clearances X> Loosen the two screws r of the level feed arm e and adjust. 1005S 6-03 LZ2-B855E,B856E...

  • Page 41: Adjusting The Stitch Length

    6. Loosen the set screw t and turn the eccentric pin y to adjust the feed amount. * After adjusting, carry out the "<Backtacking and condensed stitches>" adjustment in the next section also. LZ2-B855E,B856E 6-04...

  • Page 42: Adjusting The Needle And Feed Mechanism Timing

    * If the needle and feed timing has been adjusted, you should also adjust “6-11. Adjusting the needle and ro- tary hook timing”. (Refer to page 6-09.) For the B856E, “6-18. Adjusting the timing of the thread trimming” should also be adjusted. (Refer to page 6- 15.) 0600M 6-05 LZ2-B855E,B856E...

  • Page 43: Adjusting The Forward/Back Position Of The Needle Bar

    * After making this adjustment, you should also carry out the adjustment in "6-9. Adjusting the right/left position of the needle bar" (Page 6-07). LZ2-B855E,B856E 6-06...

  • Page 44: Adjusting The Right/Left Position Of The Needle Bar

    Repeat this step until the needle home position is aligned with the center of the needle plate hole. 8. Press the TEST key t on the operation panel. The TEST indicator y will switch off and the sewing machine will return to normal sewing mode. Then press the power switch to turn off the power. 6-07 LZ2-B855E,B856E...

  • Page 45: Adjusting The Needle Bar Height

    (Refer to page 6-09.) * When remove the feed dog. be sure to adjust “6-5. Adjusting the forward/back, right/left position of the feed dog”. (Refer to page 6-03.) 0602M Accessory timing gauge Index mark Max.zigzag width 08mm 10mm 05mm LZ2-B855E,B856E 6-08...

  • Page 46: Adjusting The Needle And Rotary Hook Timing

    * The end of the rotary hook holder q must never ex- tend to the right of end A of the inner rotary hook w. 1. Loosen the screw e and adjust the position of the ro- tary hook holder q. 0-0.5mm 2. Securely tighten the screw e. 0608M 6-09 LZ2-B855E,B856E...

  • Page 47: Adjusting The Synchronizer

    When mounting the pulley be sure to leave a 0.5 mm gap between the pulley edge and synchronizer. Furthermore, tighten the two machine pulley set screws so that the rear set screw is at the screw stop on the upper shaft when seen from the machine pulley turning direction. LZ2-B855E,B856E 6-10...

  • Page 48: Adjusting The Rotary Hook Lubrication Amount

    * Turn the lubrication adjustment screw e and check the lubrication amount repeatedly until the lubrica- tion amount is correct. 4. Check the lubrication amount again after the sewing machine has been used for approximately two hours. Less oil More oil 0612M 6-11 LZ2-B855E,B856E...

  • Page 49: Adjusting The Lubrication Amount Of The Needle Bar

    • In contrast, if they do not touch at all, needle zigzagging will become more and more sluggish as the sewing machine continues running, and motor skipping and seizure will result. LZ2-B855E,B856E 6-12...

  • Page 50: Adjusting The Tension Release Of Thread Trimming (B856E)

    3. After adjusting, tighten the two set screws t while pushing the thread feeding lever u gently backward. 4. To check the timing for the start of tension release, push the plunger w of the thread feeding solenoid q by hand until it reaches the position shown in the illustration. 6-13 LZ2-B855E,B856E...

  • Page 51: Adjusting The Thread Trailing Length After Thread Trimming (B856E)

    0.5mm tension as possible while still allowing the rotary disc u to rotate smoothly. 1033S The thread tension will change at this time, so be sure to re-adjust the upper thread tension. (Refer to instruction manual page 123.) LZ2-B855E,B856E 6-14...

  • Page 52: Adjusting The Triming Of The Thread Trimming (B856E)

    T mark on the face plate. Check that the knife begins to move at this point, and that it re- turns when the reference line is aligned with the U mark. 1038S 6-15 LZ2-B855E,B856E...

  • Page 53: Adjusting The Tension Of The Lower Thread Presser Spring (B856E)

    6 to 8 mm, and that the thread wiper w catches the thread firmly. Loosen the screw 7 and move the thread wiper w up or down to adjust. <Seen from the front> 6-8mm Align 1043S 1044S LZ2-B855E,B856E 6-16...

  • Page 54: Adjusting The Reverse Feed Assembly

    Set the condense stitch adjustment dial t to the maximum reverse setting when adjusting. Loosen the two screws r and move the backtack solenoid w up and down to adjust. 6-17 LZ2-B855E,B856E...
  • Page 55 6. ADJUSTMENTS LZ2-B855E,B856E 6-18...

  • Page 56: Troubleshooting

    • 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 5 minutes after turning off the power switch and disconnecting the power cord from the wall outlet before opening the face plate of the control box.
  • Page 57 Use the correct needle or the correct thread. • Is the rotary hook, bobbin case, thread take-up lever or some other part in the thread path damaged? Repair the damage, or replace the part with a new one. 0626M LZ2-B855E,B856E 7-02...

  • Page 58: Possible Cause Page

    • Is the bobbin turning smoothly? thread 0628M If the bobbin is not turning smoothly, replace the bobbin. • Is a bobbin other than the light-alloy bobbins specified by Brother Sprinning of bobbin during being used? (B856E) thread trimming (B856E) Use only bobbins which are specified by Brother.

  • Page 59: Adjust The Upper Thread Feeding Device

    Page 15. Operation panel keys do • Is appearing in the LED display? not operate. If this display appears, key operation has been locked because Instruction manual of a DIP switch setting, so the keys cannot be operated. LZ2-B855E,B856E 7-04...

  • Page 60: Electric Components

    ; a low voltage transformer is equipped with 100 V and 110 V specifications. Conversion transformer DC fan motor 2 (Cooling fan 2) Power supply transformer Power supply circuit board DC fan motor 1 (Cooling fan 1) Control circuit board Rear view 1143S 8-01 LZ2-B855E,B856E...
  • Page 61 Home position sensor Power supply circuit board DC fan motor 1 (Cooling fan 1) Operation panel Power supply transformer Synchronizer DC fan motor 2 (Cooling fan 2) Power supply circuit board 1146S Power supply transformer Zigzag pulse motor Solenoid etc. LZ2-B855E,B856E 8-02...
  • Page 62 Machine head Oil pan Machine motor connector of 1148S power supply circuit board Power supply circuit board 1143S < DIP switches, ROM and fuses positions > DIP SW1 P-ROM DIP SW2 Fuse (F2) 8A Fuse (F1) 8A 1146S 8-03 LZ2-B855E,B856E...

  • Page 63: Fuse Explanation

    If the resistances are no good, replace the power supply circuit board. < If fuse F3 or fuse F4 is blown > Replace the power supply circuit board. (There is a possibility that the component on the power supply circuit board is damaged.) LZ2-B855E,B856E 8-04...
  • Page 64 CODE–S47680000) If the resistances are no good, replace the control circuit board. < If fuse F2 is blown > Replace the control circuit board. (There is a possibility that the component on the control circuit board is damaged.) 8-05 LZ2-B855E,B856E...

  • Page 65: Connectors

    < Standing pedal (option) > Harness of the solenoid Harness of the type presser foot lifter standing pedal 1152S 1151S Relay harness < Reflection pattern switch (option) > 1153S Harness of the reflection pattern switch P23 EXPAND2 P22 EXPAND1 LZ2-B855E,B856E 8-06...
  • Page 66 P13 FAN1 P23 EXPAND2 P22 EXPAND1 P4 PANEL P14 AC18V P21 L-THREAD P3 SYNC P2 VR P1 FAN2 P15 DC300V 1146S P20 AC17V/AC30V P18 SOL P16 NPM P19 OPSOL P17 POWER(OP) Power supply circuit board CN4 CN2 1147S 8-07 LZ2-B855E,B856E...
  • Page 67 Signal name Probable symptoms due to poor contact +40V The presser foot does not operate automatically. 0V(P0V) The knee switch does not have any effect. The presser foot operating is not correct. Presser foot lifter SOL Knee switch input LZ2-B855E,B856E 8-08...
  • Page 68 Key scan input 2 Panel control output (OC) Panel output (A) Panel output (B) Panel output (C) Panel output (D) Panel output (E) Panel output (F) Panel output (G) Panel control output (PLED) Sensor input Buzzer output P5 [SW(OP)] (not attached) 8-09 LZ2-B855E,B856E...
  • Page 69 P10 [HEAD] (not attached) P11 [ORG] (JAPAN SOLDERLESS TERMINAL XHP-12) Pin No. Signal name Probable symptoms due to poor contact +24V Home position can not be found. Error code Ec1 appears. Home position sensor P12 [OPVR] (not attached) LZ2-B855E,B856E 8-10...
  • Page 70 AC18V(E) AC20V(F) AC20V(F) P15 [DC300V](MOLEX 3191-02R1) Pin No. Signal name Probable symptoms due to poor contact +300V Home position can not be found. 0V(DC300) The machine does not zigzag. The zigzagging is not correct. Error code Ec1 appears. 8-11 LZ2-B855E,B856E...
  • Page 71 TR40V (Thread wiper SOL) +40V (Upper thread feeding SOL) P19 [OPSOL] (not attached) P20 [AC17V/AC30V] (JAPAN SOLDERLESS TERMINAL VHR-5N) Pin No. Signal name Probable symptoms due to poor contact Error code EE5 appears. AC30V AC30V AC17V AC17V P21 [L-THREAD] (not attached) LZ2-B855E,B856E 8-12...
  • Page 72 Probable symptoms due to poor contact The lamp of reflection pattern switch does not light or one is flickering. +24V +24V +24V +24V TOUT1 TOUT2 TOUT3 TOUT4 * Only pins 1 and 17 are used by the lamp mirror switch. 8-13 LZ2-B855E,B856E...
  • Page 73 Probable symptoms due to poor contact The reflection pattern switch does not operate. OPSEN1 OPSEN2 OPSEN3 OPSEN4 OPSEN5 OPSEN6 OPSEN7 OPSEN8 OPSEN9 OPSEN10 OPSEN11 OPSEN12 +24V +24V +24V +24V * Only pins 1 and 17 are used by the lamp mirror switch. LZ2-B855E,B856E 8-14...
  • Page 74 Home position can not be found. 0V(DC300) The machine does not zigzag. The zigzagging is not correct. Error code Ec1 appears. CN6 (MOLEX 5197-2) Pin No. Signal name Probable symptoms due to poor contact Error code EE2, or EF2 appears. Resistor Resistor 8-15 LZ2-B855E,B856E...
  • Page 75 Power does not come on. AC input R phase Home position can not be found. The machine does not zigzag. AC input S phase AC input T phase The zigzagging is not correct. Error code Ec1, or EE3 appears. LZ2-B855E,B856E 8-16...

  • Page 76: Summary Of Dip Switches

    Left stop setting No setting Right stop setting DIPSW2-3 : OFF Left end Left end Right end DIPSW2-3 : ON Left end Right end Right end Note 2 : When the DIP SW2-6 was switched, be sure to reset all. 8-17 LZ2-B855E,B856E...

  • Page 77: Memory Switches

    Before end backtack is sewn, speed does not change from high speed to low speed. (When OFF, speed increases to backtack speed after deceleration.) (Set to OFF) (Set to OFF) Sewing can be stopped during start backtack sewing. (Set to OFF) LZ2-B855E,B856E 8-18...
  • Page 78 (Set to OFF) (Note 3) (Set to OFF) (Note 3) (Set to OFF) (Note 3) (Set to OFF) (Note 3) (Set to OFF) (Note 3) (Set to OFF) (Note 3) (Set to OFF) (Note 3) (Set to OFF) (Note 3) 8-19 LZ2-B855E,B856E...
  • Page 79 If the part code of the main PCB ends with -001, No. 81-98 are not displayed. Note 4 : If the P-ROM label is MN-B-D and the part code of the main PCB ends with -001 and -101 this function is not available. LZ2-B855E,B856E 8-20...

  • Page 80: Parameters

    Operation time of the presser foot signal being ON again (x 10 msec) (Soft down operation) 00 - 47 Switching timing from start backtack to normal zigzag sewing (See Remarks.) 00 - 47 Switching timing from normal zigzag sewing to end backtack (See Remarks) 8-21 LZ2-B855E,B856E...
  • Page 81 Limit value of frequency command feedback amount when speed is increasing. (** Low voltage spec. : 20, Medium & high voltage spec. : 46) 10 - 90 (Note 3) 10 - 99 (Note 3) 05 - 70 (Note 3) LZ2-B855E,B856E 8-22...
  • Page 82 Note 2 Control circuit boards which have -001 or -101 as the final three digits of their part number do not support this function. Note 3 This is related to motor control. It should not normally be changed. 8-23 LZ2-B855E,B856E...

  • Page 83: Speed Parameter

    If you do not do so, the buzzer will intermittently sound until you press any of the keys or sewing starts. (If you exit the setting mode without doing the operation above, the buzzer will stop sounding if you enter the setting mode once again and have AU displayed.) LZ2-B855E,B856E 8-24...

  • Page 84: Initialization

    Needle zigzag data problem Malfunction of P-ROM or poor connection Malfunction of control circuit board Problem with custom data Communication problem between CPUs Malfunction of control circuit board Noise affecting transmission Mismatch between control circuit board and PROM versions 8-25 LZ2-B855E,B856E...
  • Page 85 5Et will appear on the LED display. When this happens, normal operation after turning on the power will return when the SET key is pressed. EF1 : When set to ON memory switch No. 16, EF1 (overtime error) not occurs. LZ2-B855E,B856E 8-26...

  • Page 86: Troubleshooting

    Indication appear lamp on panel lit? (page 8-30) on the display Turn the machine pulley to move the needle bar to the needle up stop position. Does the needle bar #2-1 move before Ec1 is indicated on panel. #2-2 8-27 LZ2-B855E,B856E...
  • Page 87 8. ELECTRIC COMPONENTS Press SET key LED Indication flash on the display Press SET key Depress treadle a little LZ2-B855E,B856E 8-28...
  • Page 88 Needle zigzagging Depress treadle deep Machine starts running at a high speed Treadle is back to the neutral position Machine stops Depress treadle backward Machine runs and stops at the needle up stop position. Normal 8-29 LZ2-B855E,B856E...
  • Page 89 Change the power supply circuit board. Check the fuse F4 on power Change the power supply circuit board. supply circuit board Check the fuse F1,F2 on power supply circuit board Change the power supply circuit board. Check the power supply circuit board. LZ2-B855E,B856E 8-30...

  • Page 90: Problem Solution And Measures

    Malfunction of control circuit board 2. Broken fuse F2 on the control When fuse F2 has blown, other parts have blown on Control circuit board circuit board control circuit board too. 8-31 LZ2-B855E,B856E...
  • Page 91 3. Malfunction of connection Check 4P connector from transformer is securely plugged in on the power supply circuit board. ( See below) For 100V,200V === CN2(200V) For 110V,220V,240V,380V,400V,415V === CN3(220V) For 230V === CN4(230V/240V) LZ2-B855E,B856E 8-32...
  • Page 92 Check P3 (SYNC) connector is securely plugged in on Synchronizer The UP| the control circuit board. display 2. Malfunction of synchronizer Synchronizer remains without changing even when the machine pulley is turned to the needle up stop position. 8-33 LZ2-B855E,B856E...

  • Page 93: Control Circuit Block Diagram

    Presser foot lifter SOL White Knee SW EARTH Power swich Black 1619P 1261R 1619R 1261P Black White White White 1619P 1619R 1619R 1619P 1619P Black Black DC fan White Green/Yellow Green/Yellow Presser foot lifter Treadle unit Knee SW Machine motor Power LZ2-B855E,B856E 8-34...
  • Page 94 SERVICE MANUAL BROTHER INDUSTRIES, LTD. 15-1, Naeshiro-cho, Mizuho-ku, Nagoya 467-8561, Japan. Phone: 81-52-824-2177 Printed in Japan 118-855,856 I1040806F 2001.04 (1)

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