Brother MD-741B Service Manual Download Page 72

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S-7200B

13. TROUBLESHOOTING

Problem Possible

cause

Page

5 Skipped stitches at sewing

start
Thread unravelling at
sewing start

Is the thread take-up spring tension too strong?

Reduce the tension of the thread take-up spring.

Is the thread take-up spring operating range too large?

Lower the position of the thread take-up spring.

Are the trailing lengths of the upper threads too short after thread
trimming?

Adjust the pretension.

Are the threads not being trimmed cleanly?

Sharpen the fixed knives, or replace the fixed and movable
knives if necessary.

Is the needle too wide?

Try using a needle with a count that is one lower than the
current needle.

Is the length of thread trailing out from the bobbin case after thread
trimming too short.

If the bobbin is spinning loosely, replace the anti-spin spring in
the bobbin case.

Is the sewing speed too fast at the sewing start?

Use the slow start feature.

Is the needle up stop position too high?

Adjust the needle up stop position.

Instruction

manual

Instruction

manual

Instruction

manual

34, 35

6 Uneven

seam

Is the presser foot pressure too weak?

Adjust the presser foot pressure.

Is the feed dog too low?

Adjust the feed dog height.

Is the bobbin scratched?

If the bobbin is damaged, smooth it with an oiled grindstone or
replace it.

Instruction

manual

7 Large degree of puckering

(excess tension)

Is the upper thread tension too strong?

Make the upper thread tension as weak as possible.

Is the lower thread tension too strong?

Make the lower thread tension as weak as possible.

Is the needle tip blunt?

Replace the needle if it is blunt.

Is the needle too thick?

Replace with as thin a needle as possible.

Are the thread take-up spring tensions too strong?

Make the thread take-up spring tension as weak as possible.

Is the thread take-up spring operating range too large?

Lower the position of the thread take-up spring to as low a
position as possible.

Is the presser foot pressure too strong?

Adjust the presser foot pressure.

Is the sewing speed too fast?

Use the sewing speed control keys to gradually reduce the
sewing speed.

Is the angle of the feed dog correct?

Tilt the front of the feed dog down slightly.

Instruction

manual

Instruction

manual

Instruction

manual

Instruction

manual

8 Material

slippage

Is the presser foot pressure too strong?

Adjust the presser foot pressure.

Instruction

manual

0749M

0473M

0978M

0750M

Summary of Contents for MD-741B

Page 1: ...S 7200B MD 741B 751B 741C 751C Please read this manual before making any adjustments SINGLE NEEDLE DIRECT DRIVE STRAIGHT LOCK STITCHER WITH THREAD TRIMMER SERVICE MANUAL ...

Page 2: ... SAFETY INSTRUCTIONS and the whole of this manual to understand this product before you start maintenance 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 ...

Page 3: ...h or serious injury CAUTION The instructions which follow this term indicate situations where failure to follow the instructions could cause injury when using the machine or physical damage to equipment and surroundings Symbols This symbol indicates something that you should be careful of The picture inside the triangle indicates the nature of the caution that must be taken For example the symbol ...

Page 4: ...g may cause problems with correct operation Installation Machine installation should only be carried out by a qualified technician Contact your Brother dealer or a qualified electrician for any electrical work that may need to be done The sewing machine weighs more than 44 kg The installation should be carried out by two or more people Do not connent the power cord until installation is complete T...

Page 5: ...ng it back or returning it to its original position If only one hand is used the weight of the machine head may cause your hand to slip and your hand may get caught Be sure to wear protective goggles and gloves when handling the lubricating oil and grease so that they do not get into your eyes or onto your skin otherwise inflammation can result Furthermore do not drink the oil or eat the grease un...

Page 6: ...bels have been removed or are difficult to read please contact your nearest Brother dealer 1 2 3 Be sure to connect the ground If the ground connection is not secure you run a high risk of receiving a serious electric shock and problems with correct operation may also occur Safety devices A Finger guard B Thread take up cover 4 Direction of operation 3629M Control box Oil pan ...

Page 7: ...e up amount 3 specifications 33 6 13 Adjusting the needle up stop position When using the operation panel 34 6 14 Setting the needle up stop position and needle down stop position If using the control box panel 35 6 15 Adjusting the treadle 37 6 16 Adjusting the presser foot floating amount minute lifting amount 37 7 REPLACING PARTS 38 7 1 Fixed knife 38 7 2 Movable knife 38 7 3 Motor and timing b...

Page 8: ...peed 1 800 rpm Max stitch length 4 2 mm 5 mm Lifting lever 6 mm Presser foot height Knee lifter 16 mm Feed dog height 0 8 mm 1 2 mm Needle DB 1 DP 5 NS 9 11 11 18 19 22 Motor AC servo motor 4 pole 450W Control circuit Microprocessor When sewing at speeds of 4 000 rpm or higher set the stitch length to 4 2 mm or less Rotary hook 33S 43S 303 403 333 433 305 405 45S 453 Lubricated for light materials...

Page 9: ... used Carrying the machine The machine should be carried by the arm by two people as shown in the illustration Hold the motor cover A by hand also so that the pulley does not rotate Tilting back the machine head Hold section B with your foot so that the table does not move and then push the arm with both hands to tilt back the machine head Returning the machine head to the upright position 1 Clear...

Page 10: ...he maximum speed that is set here when the treadle is fully depressed 3 The start backtack sewing speed can be set to a speed from 220 rpm to 3 000 rpm The factory default setting is 1 800 rpm 4 When sewing starts the sewing speed display disappears and returns to the orange display NOTE When the main display is green normal key operations such as the start backtack key and the fixed stitch key ca...

Page 11: ... are present can result in severe injury ON Presser foot is lowered Export specification 1 Presser foot position when the treadle is returned to the neutral position after thread trimming OFF Presser foot is kept raised Japanese specification only See NOTE 1 ON Enabled 2 Presser foot lowering when the treadle is depressed to step 1 See NOTE 2 OFF Disabled ON The lock will not be released even if t...

Page 12: ...the setting range 4 The buzzer will sound for approximately 1 second and then the setting will be accepted The main display will return to the stitch number display orange Press for 2 seconds or more NOTE If you depress the treadle before pressing the ENTER key the main display will return to orange and the setting value will not be changed If you change the function number after changing the sett...

Page 13: ...0 4 Option actuator operation setting 0 Half stitch correction sewing 1 Single stitch correction sewing 2 Single reverse stitch correction sewing reverse feed 3 Thread trimming 4 Single end backtack cycle cancel 5 Solenoid type presser foot lifter is raised Alternating 6 Solenoid type presser foot lifter is raised Momentary 12 0 0 1 Presser foot status when treadle is returned to neutral after thr...

Page 14: ...h number I 26 0 0 1 Speed for moving to end backtack 0 Decelerates to low speed then end backtacking starts 1 Decelerates to end backtacking speed then end backtacking starts Cycle time can be shortened 27 0 0 1 Continuous backtacking operation 0 Stitch number A B C D 1 Stitch number A B x D times 28 0 0 1 Feed direction when stopping immediately after start backtacking 0 Quick reverse solenoid tu...

Page 15: ...oft down mode 0 Automatic mode See NOTE 8 1 Manual mode See NOTE 9 36 180 seconds 3 minutes 0 240 seconds Presser foot lift time 0 No timer function does not drop 1 240 Presser foot drops after set time 37 0 0 1 Automatic presser foot lifter type 0 Solenoid type See NOTE 10 1 Pneumatic type See NOTE 11 38 NOTE 12 40 ms 20 120 ms Delay time for presser foot lifter solenoid to turn on after presser ...

Page 16: ...wered 1 Above operation not used only possible using presser foot lifter pedal 49 0 0 1 Alternate standing operation pedal and treadle operation See NOTE 15 0 Treadle operation is disabled after standing operation pedal is used 1 Treadle operation can also be used after standing operation pedal is used alternate operation is possible 50 4000 rpm 300 5000 rpm Automatic deceleration speed when quick...

Page 17: ...bled 2 Synchronization of main shaft at automatic deceleration speed set by No 50 59 0 degrees 0 355 degrees Do not change this setting 60 150 degrees 0 355 degrees Do not change this setting NOTE 17 Setting is only enabled when DIP switch 2 is set to ON Needle breakage prevention function specifications Use Function No 50 to set the automatic deceleration speed when the quick reverse mechanism ha...

Page 18: ... reverse operation starts during highest needle position stop operation 66 NOTE 18 0 0 1 Presser foot lift timing during highest needle position stop operation 0 Presser foot is raised after needle bar is raised 1 Presser foot is raised before needle bar lift operation starts See NOTE 19 67 NOTE 18 0 degrees 20 20 degrees Highest needle position stop position setting 68 NOTE 20 0 0 1 Seam matching...

Page 19: ...s pressed the sewing speed becomes 1 000 rpm The speed can be changed by setting Function No 122 When the medium speed switch is pressed the sewing speed becomes 3 000 rpm The speed can be changed by setting Function No 121 When the high speed switch is pressed the sewing speed returns to the maximum sewing speed that has been set using the MAX key When set as an option actuator Connect to connect...

Page 20: ...es The time of 10 seconds can be changed by setting Function No 72 Function No 71 can be used to set the number of stitches until the puller is lowered after sewing starts If the puller is raised in synchronization with the automatic presser foot lifter while the sewing machine is stopped after thread trimming this operation occurs When set to needle cooler synchronized output during operation Out...

Page 21: ... chain stitch thread trimming thread wiping After thread trimming the thread wiper signal is output Use Function No 109 and No 110 to set the timer operation When set to pneumatic wiper After thread trimming output is synchronized with the automatic presser foot lifter Use Function No 111 and No 112 to set the timer operation When the presser foot is lowered option output turns off Motor Option Ne...

Page 22: ...en Function No 63 is set to 1 NOTE 24 Setting is enabled when Function No 22 or No 26 is set to 1 NOTE 25 Setting is enabled when Function No 68 is set to 1 The stopping position is the angle after the need up signal turns on NOTE 26 Setting is enabled when Function No 68 is set to 1 The reverse feed mechanism switches at the stopping position When the stopping time has elapsed the sewing machine ...

Page 23: ...t for standing operation variable speed pedal 88 0 0 2 Treadle speed curve 0 Constant 1 Curves downward 2 Curves upward Settings indicated with are enabled when the power is turned off and then back on With the treadle neutral position as the 0 point the values in the forward direction are plus values and those in the backward direction are minus values so that the speeds accelerate or decelerate ...

Page 24: ... 0 3 Lock level for operation panel lock 0 FUNC key 1 FUNC key MAX key 2 FUNC key MAX key Correction key 3 FUNC key MAX key Correction key Stitch number key 102 0 Do not change this setting 103 0 needles 0 99 needles No of pocket sewing stitches J 104 0 needles 0 99 needles No of pocket sewing stitches K 105 0 needles 0 99 needles No of pocket sewing stitches L 106 0 needles 0 99 needles No of poc...

Page 25: ...for option output C7 NOTE 30 Setting is enabled when Function No 70 is set to 2 NOTE 31 Setting is enabled when Function No 70 is set to 4 NOTE 32 Setting is enabled when Function No 70 is set to 5 NOTE 33 Setting is enabled when Function No 70 is set to 2 or 5 NOTE 34 The stitch number control output signal can be set in accordance with the variable input signal Stitch number control output signa...

Page 26: ...F E Pocket sewing 1 3 E F G H I H G F E Pocket sewing 2 4 E F G H I I H G F E 5 E F G H I J I H G F E 6 E F G H I J K L M NOTE 35 Setting is enabled when Function No 37 is set to 0 NOTE 36 Setting is enabled when Function No 37 is set to 1 NOTE 37 When set to 1 stitch number G is set for function No 23 When set to 2 stitch number G is set for function No 23 and stitch number H is set for Function ...

Page 27: ...t change this setting 128 0 0 3 Flicker reduction function when flickering occurs from fluorescent light 0 None 1 Medium flicker reduction 2 Low flicker reduction 3 High flicker reduction 4 Do not use this setting otherwise the motor will overheat 129 0 2 2 Motor acceleration gain Do not change this setting 130 0 2 2 Motor deceleration gain Do not change this setting 131 Do not change this setting...

Page 28: ... 1 While pressing the FUNC key on the operation panel turn on the power switch The main display will change to orange and iniT FunC will be displayed 2 Press the ENTER key Initialization of the function setting data will be carried out and the iniT FunC display will change to green 3 After this the operation panel and the treadle can be operated When an operation is carried out the display will re...

Page 29: ...ult in severe injury 1 Set DIP switch 3 to OFF This will cancel the lock so that the functions can be set 2 While pressing the end backtack key 1 press the power switch 2 to turn on the power 3 1 Press the start backtack key 3 so that r is displayed in the top row of the stitch number display 2 Press the end backtack key 1 to set the value in the bottom row of the stitch number display to 1 4 Disp...

Page 30: ...mal sewing speed for 8 seconds Any type of paper can be used as the lubrication amount check sheet 1 5 Check the amount of oil which has spattered onto the sheet If adjustment is necessary carry out the following operations in Adjusting the lubrication amount NOTE If the lubrication amount does not match the correct amount shown in the illustration at left if the amount of spattered oil is too muc...

Page 31: ...to slip and your hand may get caught Turn off the power switch and disconnect the power cord from the wall outlet at the following times otherwise the machine may operate if the treadle is depressed by mistake which could result in injury When carrying out inspection adjustment and maintenance When replacing consumable parts such as the rotary hook and knife If the power switch needs to be left on...

Page 32: ... the machine head and the table hole is 1 5 mm If the clearance is 3 5 mm or more install the safety switch 1 so that the washer 2 is on the machine head side as shown in Figure B If the position cannot be satisfactorily adjusted in this way add more washers of the same thickness Safety switch operation 3689M 3690M 3691M 3692M Sewing machine Table By changing the position of the safety switch the ...

Page 33: ... table S specifications 0 1 0 24N 3 specifications 0 25 0 35N 5 specifications 0 30 0 5N 1 Push the needle thread with your finger until it is slightly higher than the thread tension bracket 5 and so that the upper thread is not pulled out 2 Pull the upper thread down until the thread take up spring 1 is at the same height as the base of the thread guide 3 and then measure the tension of the threa...

Page 34: ... become less 6 5 Adjusting the presser foot height The standard height of the presser foot 1 is 6 mm when the presser foot 1 is raised by means of the lifting lever 2 1 Loosen the nut 3 of the adjustment screw 4 and then turn the adjustment screw 4 so that there is no pressure applied to the presser foot 2 Raise the lifting lever 2 The presser foot 1 will also rise 3 Remove the oil cap 5 4 Loosen ...

Page 35: ...he feed lifting rock bracket stud 3 within a range of 90 from the reference line 4 to adjust the vertical height of the feed bar 5 Fig A 5 Tighten the screw 2 If you are worried about the angle of the feed dog 1 turn the shaft 6 while carrying out the above adjustment Fig B Refer to 6 7 Adjusting the feed dog angle on the next page for details of this operation 2279M S 3 0 8mm 5 1 2mm Becomes high...

Page 36: ...n Fig C In order to prevent puckering lower the front of the feed dog 1 In order to prevent the material from slipping raise the front of the feed dog 1 5 Securely tighten the two set screws 4 If you would like to tilt the feed dog 1 further turn the feed lifting rock bracket stud 5 while carrying out the above adjustment Fig D Refer to 6 6 Adjusting the feed dog height on the previous page for de...

Page 37: ...he point of the needle should be approximately 1 mm below the needle plate 2 5 The top of the feed dog 1 and the top of the needle plate 2 should be aligned and there should be a clearance of approximately 3 mm between the point of the needle and the needle plate 2 1 Tilt back the machine head 2 Loosen the two set screws 5 and then turn the vertical cam 3 sligtly to adjust the timing Use the mark ...

Page 38: ...edle bar bush D 2 as shown in the illustration The needle should rise by 1 8 mm 2 2 mm for 5 specifications and the distance from the needle hole to the tip of the rotary hook should be 0 5 0 7 mm 2 Loosen the three set screws 5 and then align the tip of the rotary hook 3 with the center of the needle 4 The distance between the tip of the rotary hook 3 and the needle 4 should be approximately 0 0 ...

Page 39: ...trimmer cam 2 and the roller shaft 4 is 0 5 mm when the roller shaft 4 returns to the right Fig B Tighten the two set screws 5 to approximately 4 N m Movable knife and fixed knife position adjustment 1 Turn the machine pulley and then push the plunger 1 of the thread trimming solenoid with your finger 2 In this condition turn the machine pulley until the roller shaft 4 of the thread trimmer cam le...

Page 40: ...wrench 3 to loosen the set screws 2 and 3 by approximately two turns 4 Adjust the thread take up amount To increase the thread take up amount Turn the thread take up support shaft 4 clockwise so that the groove 5 is facing straight upward To return the thread take up amount to the standard setting Turn the thread take up support shaft 4 counterclockwise so that the groove 5 is facing straight down...

Page 41: ...ing value will increase up to 20 and the needle up stop position will become lower If you press the key the setting value will decrease down to 10 and the needle up stop position will become higher 4 Press the ENTER key 4 for two seconds or more A long buzzer will sound and the main display 2 will change to stitch number display mode This completes the needle up stop position setting A setting val...

Page 42: ...esponds to an angle of rotation of approximately 8 for the upper shaft Before setting DANGER Wait at least 5 minutes after turning off the power switch and disconnecting the power cord from the wall outlet before opening the face plate of the control box Touching areas where high voltages are present can result in severe injury 1 Set DIP switch 3 to OFF This will cancel the lock so that the functi...

Page 43: ... value 2 Set DIP switch 3 to ON The settings will be locked Needle down stop position 1 Example 3 1 Press the start backtack key 3 so that is displayed in the top row of the stitch number display 2 Press the end backtack key 1 to set the value 2 Set DIP switch 3 to ON The settings will be locked Becomes higher Becomes lower Becomes higher Becomes lower 0704B Becomes lower Becomes higher 3657M 0705...

Page 44: ...position in figure B The treadle stroke will then be increased by approximately 27 At this time the treadle forward and backward depression sensitivity will change so readjust if necessary 6 16 Adjusting the presser foot floating amount minute lifting amount When sewing stretch materials and materials with long pile you can make minute adjustments to the floating amount for the presser foot 1 in a...

Page 45: ...at the grease under any circumstances as they can cause vomiting and diarrhea Keep the oil out of the reach of children 7 1 Fixed knife 1 Tilt back the machine head 2 Remove the screw 1 and then remove the rotary hook stopper 2 3 Remove the screw 3 and then remove the fixed knife 4 Carry out the above steps in reverse to install the fixed knife 4 Sharpening the fixed knife If the cutting performan...

Page 46: ...til the four set screws 8 on the joint 7 are facing toward the front Loosen the two set screws 8 at the left by about five turns each 7 Remove the three screws 9 and then remove the machine pulley 5 8 Remove the three screws 10 and then remove the motor 11 If it is difficult to remove the motor 11 tighten one of the removed screws 10 into the screw hole a at the left or right The motor 11 can then...

Page 47: ... line d and the mark e may move out of alignment when tightening the screws but this is not a problem 6 Adjust the positions of the machine pulley 5 and timing pulley D 6 as follows 1 Tilt back the machine head 2 Turn timing pulley D 6 forward to lower the feed dog 15 until it is at the same height as the needle plate 16 3 Turn the machine pulley 5 forward to adjust so that the tip of the needle i...

Page 48: ...int of the needle and the needle plate 16 If it is not in the correct position carry out the following steps 1 Tilt back the machine head and then loosen the two set screws 18 2 Turn timing pulley D 6 forward to lower the feed dog 15 until it is at the same height as the needle plate 16 3 While holding the vertical cam 19 with one hand so that it will not move turn the machine pulley 5 forward to ...

Page 49: ... 4 and the needle After installing the rotary hook RP adjust the needle and rotary hook timing Refer to page 31 6 Install the feed dog 2 7 Install the needle plate 1 Adjust the installation position of the feed dog 2 so that it is in the middle of the needle plate 1 groove 8 Install the presser foot Adjusting the adjusting screw Tighten the adjusting screw 5 as far as it will go and then turn it b...

Page 50: ...he holes of each part as shown in the arrow until a small amount of grease overflows 2 Tighten the screws to force the grease in 3 Wipe away any excess grease from around the screws 4 Apply grease to the meshing areas areas of each part 5 Install each part to the sewing machine Feed bar shaft unit Grease Grease 2317M Grease Grease 0742B Grease Grease Be particularly sure to apply grease to the gro...

Page 51: ... If you do not apply grease when the GrEASEUP notification appears the notification will continue to appear and the power indicator 3 will flash each time the power is turned on until you reset the notification by carrying out the procedure on the following page If you continue to use the sewing machine after the GrEASEUP notification appears without applying grease or without carrying out the res...

Page 52: ...in the main display 1 and the buzzer will sound 2 Press the RESET key 2 The main display 1 will change to stitch number display mode 3 Press and hold the LOCK key 4 for 2 seconds or more The lock icon 5 will switch off and the lock will be released 4 Press the FUNC Function key 6 n 134 Pxxx will appear in green in the main display 1 Pxxx indicates the grease consumption amount For example P100 mea...

Page 53: ... GU in the stitch number display 1 will stop flashing and disappear and sewing will be possible when the treadle is depressed The power indicator 2 will flash NOTE GU will appear each time the power is turned on until you apply grease and reset the notification by carrying out the reset procedure on the following page If you continue to use the sewing machine after the GU notification appears with...

Page 54: ...ng procedure to reset the grease consumption amount 1 Set DIP switch 3 inside the control box to OFF This will cancel the lock so that the functions can be set 2 While pressing the end backtack key 4 press the power switch to turn on the power 3 Press the start backtack key 3 so that G is displayed in the top row of the stitch number display 4 Press the end backtack key 4 to set the value in the b...

Page 55: ... the control box 4 and the electrical brake is then applied to slow the DD motor 5 2 The encoder circuit board that is installed to the DD motor 5 sends a signal to the control box 4 so that the electrical brake is applied in order to stop the sewing machine at the stopping position needle up or needle down set by the pulley 6 that is attached to the DD motor 5 C When the treadle is depressed back...

Page 56: ...emove the cable tie 1 and the shielded wire clips 2 and 3 in that order and then disconnect all of the connectors 4 to 7 from the sewing machine Be careful not to break the pawls of connectors 5 6 and 7 2 Disconnect the power supply connector 8 and the motor connector 9 3 Disconnect the ground wire 10 4 Loosen the nuts 11 and 12 without removing them 5 Remove the bolt 13 and nut 14 6 Pivot the con...

Page 57: ...plate Model MD 7410 Single phase MD 7510 Three phase Serial No 1 4 4 5 2 1 Japan 2 Asia Middle East 3 USA Mexico 4 Canada 5 Oceania C TICK 7 Turkey North Africa 9 China Destination L Europe Greece CE 1 100V 2 110V 3 200V 5 220 240V Power supply voltage 8 380 415V 4 1 forward 1 backward step type Treadle unit 6 2 forward 2 backward step type Operation panel 4 External Sewing machine 1 S 7200A Phase...

Page 58: ...S 7200B 10 CONTROL BOX AND MOTOR 51 Motor Serial No 2326M 2327M ...

Page 59: ...CN8 Coupler connector Connect to power supply circuit board connectors CN1 Control power supply connector Connect to transformer connectors CN2 Treadle connector Connect to treadle unit connector CN3 Standing operation connector Connect to plug sold separately for standing operation CN15 Puller connector Connect to solenoid for puller or other device CN11 Option connector 1 Connect to sewing speed...

Page 60: ...achine shaft sync signal 45 pulses stitch 8 STBY Operation signal output H level Operation in progress 9 S0V 0V GND 10 ENC A A phase signal output Encoder A phase 180 pulses stitch 11 ENC B B phase signal output Encoder B phase 180 pulses stitch Open collector output Connector CN9 Signal name Remarks 1 5V DC 5V 2 UNTH_LED Stitch counter LED signal output Stitch counter warning LED 3 UNTH_SW Stitch...

Page 61: ...g an ohmmeter in the x 1 range If the value is as shown in the table below the connector is normal Between 2 3 Between 3 4 Between 4 2 Approx 1 6Ω Power switch 1 Disconnect the power supply connector 6P 2 from the control box 2 Turn on the power switch 3 Measure the voltage at the power supply connector 2 using the AC voltage range of a multimeter and check that the voltage is within the allowable...

Page 62: ... Quick reverse solenoid Approx 4 8Ω When actuator is pressed 0Ω Between 6 13 When actuator is released Ω When machine head is upright switch ON 0 Ω Between 7 14 When machine head is tilted back switch OFF Ω Solenoid type presser lifter connector 1 Disconnect the solenoid type presser lifter connector 6P 2 from the control circuit board 2 Measure the resistance of the solenoid type presser lifter c...

Page 63: ...andard depression strokes on page 58 Set the neutral position maximum forward position and maximum backward position The first modulation position for the treadle depression force is set automatically D Depression force When depressed forward and depressed backward The depression force hardly changes at all from the start of depression until full depression When depressed forward and depressed bac...

Page 64: ...mum speed reaching point S5 1 S5 1 S5 Maximum forward depression point 14 5 12 14 5 32 81 S6 Back automatic presser lifter operating point 2 NOTE 2 14 80 S7 Thread trimmer operating point 5 22 5 35 S8 Maximum back depression point 8 28 8 43 NOTE 1 Setting is enabled when DIP switch 1 is set to ON and Function No 13 is set to 1 NOTE 2 Setting is enabled when Function No 12 is set to 0 When the conn...

Page 65: ...t the operating positions for the depression stroke For sewing machines with operation panel make the settings using the operation panel Refer to A For the operation panel For sewing machines without operation panel make the settings using the control box panel Refer to B For the control box panel A For the operation panel 1 Signal setting entry 1 Turn off the power switch 1 2 Set DIP switch No 4 ...

Page 66: ...d position With the treadle depressed backward to the maximum backward position press the thread trimming key 2 Pd x xxx will appear in the main display 3 5 Completion of setting 1 Press the ENTER key 4 The buzzer will sound and the main display 3 will switch off NOTE If you do not press the ENTER key 4 the settings will not be memorized 2 Turn off the power switch 1 3 Set DIP switch No 4 to OFF 2...

Page 67: ... No 4 to ON 3 While pressing the end backtack key 2 turn on the power switch 1 PF will appear in the stitch number display 3 2 Memorizing the maximum forward position With the treadle depressed forward to the maximum forward position press the start backtack key 4 Pn will appear in the stitch number display 3 3193M 0652B 3195M 3196M ...

Page 68: ...ey 4 Pr will appear in the stitch number display 3 4 Memorizing the maximum backward position With the treadle depressed backward to the maximum backward position press the start backtack key 4 The stitch number display 3 will switch off 5 Completion of setting 1 Turn off the power switch 1 2 Set DIP switch No 4 to OFF 3197M 3198M 0653B ...

Page 69: ...he 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 1 Connect the foot plug 1 to connector CN3 on the control circuit board 2 Connect the standing pedal connector 2 to the foot plug 1 3 Secure the cord 3 of the standing pedal with the shielded wire clip 5 an...

Page 70: ...nnector 1 DC 8 V 2 High speed switch 3 Thread trimmer switch 4 SOV 5 Spare 6 Low speed switch 7 Presser foot switch 8 Variable speed input 9 Ground NOTE Connector types Manufacturer Connector No Connector terminal MOLEX 1292 P 1380 TL 0702B 1868M 1867M High speed Thread trimming Low speed Presser foot High speed Thread trimming Low speed Presser foot ...

Page 71: ...the upper thread tension too strong Adjust the lower thread tension or upper thread tension Instruction manual 3 Loops appear in seam Is the thread path not smooth enough Use a file with a fine grain or sandpaper to polish smooth the thread path Is the bobbin not turning smoothly Pull out the lower thread to check that there is no slackness in the thread tension or replace the bobbin or bobbin cas...

Page 72: ... too weak Adjust the presser foot pressure Is the feed dog too low Adjust the feed dog height Is the bobbin scratched If the bobbin is damaged smooth it with an oiled grindstone or replace it Instruction manual 28 7 Large degree of puckering excess tension Is the upper thread tension too strong Make the upper thread tension as weak as possible Is the lower thread tension too strong Make the lower ...

Page 73: ...ad the thread correctly Is the rotary hook sufficiently lubricated 0 3 specifications If the oil gauge is down to the lower reference line in the oil gauge window add more oil Is the upper or lower thread tension too weak or too strong Adjust the upper thread or lower thread tension Is the upper thread may be loose because the thread take up spring operating range is too small Adjust the position ...

Page 74: ...with product liability regulations Instruction manual 30 31 30 14 Oil gauge 1 is not visible in oil gauge window Is the oil tank empty 0 3 specifications Fill the oil tank with oil Instruction manual 15 Machine does not operate when power is turned on and treadle is pressed Is the power supply connector disconnected from the control box Insert the connector securely Instruction manual 16 Machine d...

Page 75: ...the control box Insert the connector securely Is the operation panel connector inside the control box disconnected Insert the connector securely Instruction manual Instruction manual 19 GrEASEUP or GU flashes in the panel display when the power switch is turned on This display is to notify you that it is time to apply grease Apply grease 44 46 2196M 3154M ...

Page 76: ...tage Is the power supply voltage abnormally high Check Problem with control box Replace the control box 50 50 49 Err 2 Overcurrent Is the electrical equipment connector inside the control box disconnected Insert the connector securely 52 Err 3 Encoder error Is the encoder connector inside the control box disconnected Insert the connector securely 52 Err 4 Motor lock Is the motor connector disconne...

Page 77: ...tion panel or control box Replace the operation panel or control box 52 49 Err 8 Over time This appears on the display when the sewing machine has been operating continuously for 3 minutes or more Turn the power switch off and then back on again and then operate the sewing machine normally Err 9 Motor overheating abnormally This is displayed when the motor becomes abnormally hot and the temperatur...

Page 78: ...ce the control box 39 49 Err 16 Thread trimming solenoid timeout This is displayed if the sewing machine motor locks during thread trimming Remove any thread scraps that may be blocking the motor Check that there are no problems with the thread trimming mechanism Err 18 EEROM error This is displayed if data could not be correctly read from or written to the memory element on the control P C board ...

Page 79: ... be used for a certain period after the GrEASEUP notification appears without the grease being applied without the reset procedure being carried out Apply grease and then carry out the reset procedure 44 Err 101 diP SW4 Is DIP switch No 4 inside the control box set to ON Set DIP switch No 4 to OFF 4 If an error code that is not listed above appears or if carrying out the specified remedy does not ...

Page 80: ... switch No 4 inside the control box set to ON Set DIP switch No 4 to OFF 4 1 Overvoltage 2 Overcurrent 3 Encoder error 4 Motor lock 5 Safety switch operated 6 Voltage drop 7 Panel communication error 8 Over time 9 Motor overheating abnormally 10 Solenoid overcurrent 11 Problem with motor overheating sensor 12 Solenoid power supply error 13 Treadle unit error 14 Head detector unit error 15 Problem ...

Page 81: ...S 7200B 14 SEGMENT DISPLAY DEFINITION TABLE 74 14 SEGMENT DISPLAY DEFINITION TABLE LCD display character list 1203B ...

Page 82: ...S 7200B MEMO 75 ...

Page 83: ...S 7200B MEMO 76 ...

Page 84: ...SERVICE MANUAL S 7200B I6100914B 2007 03 B 1 Printed in Japan ...

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