Page 1 BAS-342G SERVICE MANUAL Please read this manual before making any adjustments. DIRECT DRIVE PROGRAMMABLE ELECTRONIC PATTERN SEWER...
Page 2 This service manual is intended for BAS-342G; be sure to read the BAS-342G instruction manual before this manual. Carefully read the “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.
Page 3: Safety Instructions
･･････ This symbol ( ) indicates something that you must do. The picture inside the circle indicates the nature of the thing that must be done. (For example, the symbol at left means “you must make the ground connection”.) BAS-342G...
Page 4 Furthermore, do not excessively bend the cords or secure them too firmly Contact your Brother dealer or a qualified electrician with staples, otherwise there is the danger that fire or for any electrical work that may need to be done.
Page 5: Maintenance And Inspection
In addition, do not subject the machine head to extra Ask your Brother dealer or a qualified electrician to force while it is tilted back. If this is not observed, the carry out any maintenance and inspection of the machine head may become unbalanced and fall electrical system.
Page 6 The following warning labels appear on the sewing machine. Please follow the instructions on the labels at all times when using the machine. If the labels have been removed or are difficult to read, please contact your nearest Brother dealer. Safety devices:...
Page 7 Tension release solenoid cover Inside cover L Motor cover Middle cover Outside cover Rear cover Fixed cover X motor cover 3957M BAS-342G...
Page 8 6-5-1. Y-feed mechanism........60 from floppy disks ..........34 6-5-2. X-feed mechanism........65 6-6. Feed covers ............70 6-7. Upper shaft mechanism ........72 6-8. Needle bar mechanism ........74 6-9. Intermittent presser foot lifter mechanism (2) ..76 6-10. Lower shaft mechanism........78 6-11. Shuttle hook mechanism........80 BAS-342G...
Page 9 7-19. Adjusting the lower shaft gear backlash..101 7-20. Adjusting the home position......103 7-20-1. Presser foot lift home position .... 103 7-20-2. X-Y feed home position ...... 104 7-21. Adjusting the needle up stop home position..106 7-22. Adjusting the needle up stop position.....107 BAS-342G...
Page 10: Specifications
Single-phase 220 V, Three-phase 220 V/380 V/400 V 500 VA Air pressure 0.5 MPa 1.8 l/min. * The number of data items and stitches that can be stored will vary depending on the number of stitches in each program. BAS-342G...
Page 11: Function Settings
Refer to “7-20. Adjusting the home position”. Error log display function Needle up stop position adjustment mode 4549Q 4544Q Refer to “2-6. Error history checking method”. Refer to “7-22. Adjusting the needle up stop position”. Input checking function 4545Q Refer to “2-7. Input checking method”. BAS-342G...
Page 12: List Of Advanced Functions
Refer to “2-5. Stitch counter checking method”. Refer to the Instruction Manual. Production counter temporary display function CF data read/write mode When SPEED indicator is illuminated 4492Q 4553Q Refer to the Instruction Manual. Refer to “3-4. Data read/write mode”. BAS-342G...
Page 13: Memory Switch Setting Method (Advanced)
RESET key while the number for that memory switch is displayed. • To return the settings for all memory switches to the default settings, keep pressing the RESET key for two or more seconds until the buzzer makes a long beep. BAS-342G...
Page 14: List Of Memory Switch Settings
Continuous split (split menu is disabled before split detection) Continuous split (split menu is always enabled) Independent split The position of the work clamp stopper must be set. (Refer to the Instruction Manual.) The mm display may differ slightly from the actual sewing size. BAS-342G...
Page 15 The operating modes given here are for the integrated-type work clamp. The same settings can also be made for separate-type work clamps, but some parts and air tubes will need to be changed. No devices are compatible with the BAS-342G. BAS-342G...
Page 16 In addition, if raising and lowering of the work clamp is disabled before home position detection is carried out, thread winding cannot be carried out before home position detection, regardless of the setting for memory switch No. 056. BAS-342G...
Page 17 0: Normal needle up position: Needle bar height increases for values in the -15 - 0 negative direction. If the setting value becomes too large in the negative direction, error “E110” may be generated at the first sewing start after the power is turned on. BAS-342G...
Page 18 [Need up reference] Changes the timing at the start of feed so that the needle zigzagging is even. [Feed end reference] Makes the timing uniform at the end of feed. This cannot be set for the BAS-342G. Home position detection operation when the program is changed Disabled Home position detection operation is disabled, but feed moves through the middle of the sewing area.
Page 19 Moving to the sewing start position when user program is changed Moves to the next sewing start position after starting. Moves to the next sewing start position at the same time as switching. Limitations on changing settings for user programs No limit User program contents cannot be changed. BAS-342G...
Page 20 “0” or “1”, the data in the temporary buffer will be cleared.), Changing gear ratio correction method when reading from a 2DD floppy disk. Automatic conversion based on model type (For the BAS-342G, data is read as BAS-342A data and then converted.) BAS-311A data is read.
Page 21 Maximum tension release force is set to maximum (The thread tension discs close at the sewing end. If the thread tension discs are open, they will be closed for approximately 1 minute.) Set memory switch No. 002 to 0. BAS-342G...
Page 22 Sensor is enabled and needle up stop position errors [E110] are detected. Disabled Home position return when sewing is paused Mechanism moves to home position and then moves to sewing start position. Mechanism steps back to the sewing start position along the sewing path without moving to the home position. BAS-342G...
Page 23 Sewing machine starts when extended option output No. 1 is ON. Program number output Disabled When the last two digits of the program number are 1 to 15, the program number is output in 4 bits to extended option output 4 to 7. BAS-342G...
Page 24: Stitch Counter Checking Method
2. Press the RESET key (7) for two seconds or more. (The cumulative number of stitches “0000” will stop flashing and illuminate, and the setting will be cleared. ) 3. When the TEST key (1) is pressed, the display will return 5058Q to the normal display. BAS-342G...
Page 25: Error History Checking Method
(6) is being pressed, the COUNTER indicator will illuminate and the stitch number counter value at the point where the error occurred will be displayed in the PROGRAM No. display (2) and the menu display (3) in units of 100 stitches. BAS-342G...
Page 26: Input Checking Method
Operate the work clamp motor by hand. Work clamp motor encoder counter value [ 6] [EnP] [-999] [999] Operate the work clamp motor by hand. Upper shaft 180 degree rotation signal [ 7] [Enn] [ 0] [179] Turn the pulley by hand. BAS-342G...
Page 27 [ 24] [in4] [ on]/[oFF] Option input (IN4) [ 25] [in5] [ on]/[oFF] Option input (IN5) [ 26] [rot] [ on]/[oFF] No devices are compatible with the BAS-342G. [ 27] [Fib] [ on]/[oFF] Fiber-type thread breakage detection (option) (IN14) BAS-342G...
Page 28 [ on] / [ oFF] Option input (IN7) [ 33] [in8] [ on] / [ oFF] Option input (IN8) [ 34] [in9] [ on] / [ oFF] Option input (IN9) [ 35] [in10] [ on] / [ oFF] Option input (IN10) BAS-342G...
Page 29: Output Checking Method
[ 53] [PM-F] When the key is pressed, the work clamp is lowered. [ 54] [CAtH] No devices are compatible with the BAS-342G. [ 55] [CL-r] The right clamp valve (clamp valve 1) is turned ON (OUT16) (*1) [ 56] [CL-L]...
Page 30 [ 63] [ WiP] Turns on the thread wiper solenoid. [ 64] [StEP] No devices are compatible with the BAS-342G. [ 65] [ oP1] Turns on option output 1. [ 66] [ oP2] Turns on option output 2.
Page 31: Software Version Checking Method
Main CPU [2.Mt] Motor CPU [3.PL] Panel CPU [4.iP] Main CPU (IPL) [5.PG] Programmer When the TEST key (5) is pressed, the display will return to the normal display and the sewing machine will change to home position standby. BAS-342G...
Page 32: Reading / Writing Data
0 - 99 100 - 999 r9 mode r1 mode 0 − 99 100 − 999 Old model series data range BAS-311G, BAS-326G, BAS-342G data range (BAS***.SEW) ISM***.SEW Sewing machine internal memory When memory switch r1 mode No. 755 = ON...
Page 33: Notes On Handling Cf Cards (Sold Separately)
: Log data The underlined portion of the name of the \BROTHER\ISM\SMDB00 folder for sewing data can be changed by changing the setting for memory switch No. 752 in order to change the folder name. Change the folder name if you would like to store sewing data for different sewing machines on a single CF card.
Page 34: Data Read/Write Mode
Extended option output data is read from the floppy disk. (*2) The sewing data that can be use with this sewing machine is data that has been created for the BAS-311G/BAS-326G /BAS-342G. Only valid when using an optional floppy disk drive.
Page 35: Reading Sewing Data From Cf Cards
If you then press the RESET key, the display will change back to [ ALL]. 4976Q Loading End data read/write mode Press the TEST key. Turn off the power switch, remove the CF card, and then close the cover of the CF slot. TEST indicator switches off BAS-342G...
Page 36: Writing Sewing Data To Cf Cards
STOP switch. If you then press the RESET key, the display will change back to [ ALL]. 4977Q Writing Press the TEST key. End data read/write mode Turn off the power switch, remove the CF card, and then close the cover of the CF slot. TEST indicator switches off BAS-342G...
Page 37: Reading Memory Switch Data From Cf Cards
CF card. 4579Q Writing Press the TEST key. End data read/write mode Turn off the power switch, remove the CF card, and then close the cover of the CF slot. TEST indicator switches off BAS-342G...
Page 38: Reading User Program Data From Cf Cards
CF card. 4579Q Writing Press the TEST key. End data read/write mode Turn off the power switch, remove the CF card, and then close the cover of the CF slot. TEST indicator switches off BAS-342G...
Page 39: Updating The Control Program
Turn on the power switch. The operation panel will switch off and the version updating will be carried out. When the initial screen turns back on, the updating is complete. Turn off the power switch, remove the CF card, and then close the cover of the CF slot. BAS-342G...
Page 40: Writing Error Log Data To Cf Card
Press the key to select the program number to be read. * Program numbers that contain no data will also be displayed at this time. * If [ ALL] is selected, all sewing data will be read at once. 4577Q BAS-342G...
Page 41: Writing Sewing Data To Floppy Disks
Select the [w 10] data read/write mode. 5064Q Press the R/W key. • [Fdd-] will change to [ ALL]. Press the key to select the program number to be written. * If [ ALL] is selected, all sewing data will be written at once. 4577Q BAS-342G...
Page 42: Reading Extended Option Output Data From A Cf Card
CF card and copied into the sewing machine's internal memory. 4498Q Loading When [ End] is displayed, the process is complete. Turn off the power switch, remove the CF card, and then close the cover of the CF slot. 4581Q BAS-342G...
Page 43: Writing Extended Option Output Data To Cf Cards
• The buzzer will sound and the extended option output data will be loaded from the floppy disk and copied into the sewing machine's internal memory. 5069Q Loading When [ End] is displayed, the process is complete. Turn off the power and remove the floppy disk. 5070Q BAS-342G...
Page 44: Mechanical Descriptions
4-2. Lower shaft and shuttle race mechanisms 1233B 1. Motor assembly 2. Upper shaft 3. Crank rod assembly 4. Rock gear 5. Lower gear 6. Lower shaft 7. Lower shaft adjusting bush 8. Lower shaft M bush 9. Driver Shuttle hook BAS-342G...
Page 45: Work Clamp Lifter Mechanism
4. Stepping foot driving lever 5. Stepping clamp lifter rod 6. Stepping clamp lifter 7. Stepping clamp lifter link 8. Stepping clamp link 9. Stepping clamp link B 1235B 10. Presser bar clamp 11. Presser bar 12. Intermittent presser foot BAS-342G...
Page 46: Intermittent Presser Foot Stroke Mechanism
4. Stepping clamp connecting rod 5. Stepping clamp arm R 6. Stepping clamp arm F 7. Stepping clamp link A 8. Stepping clamp link A 9. Stepping clamp link B 10. Presser bar clamp 11. Presser bar 12. Intermittent presser foot BAS-342G...
Page 47: Feed Mechanism
3. X gear 4. X-GT belt 5. X base plate 6. Y base plate Y direction 1238B 1. Y-feed motor assembly 2. Y motor gear 3. Y gear 4. Y-GT belt 5. Y-arm 6. X-LM guide bracket 7. Work clamp arm BAS-342G...
Page 48: Thread Trimmer Mechanism
7. Thread trimmer rod V 8. Thread trimmer lever V 9. Thread trimmer lever H 10. Thread trimmer rod H 11. Movable knife lever D 12. Movable knife lever 13. Movable knife connecting plate 14. Movable knife 15. Fixed knife BAS-342G...
Page 49: Tension Release Mechanism
4. Tension release pin 4-9. Thread wiper mechanism 5050Q 1. Thread wiper solenoid assembly 2. Thread wiper rod 3. Thread wiper crank assembly 4. Wiper When the thread wiper solenoid assembly is turned off, the wiper operates in the opposite direction. BAS-342G...
Page 50: Disassembly
Disassembly should only be carried out by a Use only the proper replacement parts as specified qualified technician. by Brother. Turn off the power switch before carrying out If any safety devices have been removed, be disassembly. If the foot switch is depressed by...
Page 51: Thread Wiper Mechanism
5-2. Thread wiper mechanism 5090Q 1. Thread wiper solenoid harness (Pull out) 2. STOP switch harness (Pull out) 3. Bolt 4. Plain washer 5. Removed plain washer (Assemble) 6. Removed bolt (Assemble) 7. Bolts with washers [2 pcs] Thread wiper unit BAS-342G...
Page 52: Work Clamp Arm Mechanism
1241B 1. Set screw 2. Needle 3. Needle bar thread guide 4. Bolts [8 pcs] 5. Bolts with washers [4 pcs] 6. Screws [2 pcs] 7. Work clamp arm assembly 8. Bolts with washers [2 pcs] 9. Feed plate BAS-342G...
Page 53: Intermittent Presser Foot Lifter Mechanism (1)
15. Stepping clamp lifter link shaft (Pull out) 7. Shoulder screw 16. Washer 8. Screw 17. Stepping clamp lifter link (Remove as unit) 9. Plain washers [2 pcs] 18. Presser bar 10. Finger guard 19. Bolt (Loosen) 20. Stepping clamp arm F BAS-342G...
Page 54: Needle Bar Mechanism
6. Rubber caps [2 pcs] 16. Needle bearing 7. Set screws [2 pcs] (Loosen) 17. Thread take-up lever assembly 8. Thread take-up support shaft 18. Washer assembly 19. Bolts [2 pcs] 9. Thread take-up support 20. Slide block guide 10. Screw (Loosen) BAS-342G...
Page 55: Upper Shaft Mechanism
27. Bobbin winder driving wheel 12. Set screws [2 pcs] (Loosen) 28. Stepping clamp cam assembly 13. Set screws [2 pcs] (Loosen) 29. Set screw (Loosen) 14. Set screws [2 pcs] (Loosen) 30. Pulley assembly 15. Set screws [2 pcs] (Loosen) BAS-342G...
Page 56: Lower Shaft Mechanism
22. Set screw (Loosen) 23. Set screw collar R 24. Set screws [2 pcs] (Loosen) 25. Rock gear shaft (Pull out from the rear of the machine) 26. Set screw collar B 27. Rock gear 28. Crank rod [Lower part] 1247B BAS-342G...
Page 57: Feed Covers
8. Bolts [20 pcs] 9. Cover rail FL assemblies [2 pcs] 10. Cover rail FR assemblies [2 pcs] 11. Outside cover assemblies [2 pcs] 12. Middle cover assemblies [2 pcs] 13. Screws [14 pcs] 14. Fixations [2 pcs] 1249B BAS-342G...
Page 58: Feed Mechanism
24. Pulley fulcrum shaft 11. Fan 25. Pulley A assembly 12. Bolts with washers [4 pcs] 26. Pulley fulcrum shaft collar 13. X motor bracket 27. X pulley bracket 14. Bolts [4 pcs] 28. X-GT belt 1250B 1251B 1252B BAS-342G...
Page 59 48. Set screws [4 pcs] (Loosen) 49. Pulley fulcrum shafts [2 pcs] 50. Pulley fulcrum shaft collars [2 pcs] 51. Pulley A assemblies [2 pcs] 52. Y pulley brackets [2 pcs] 1253B 53. Y-GT belts [2 pcs] 1254B 1255B BAS-342G...
Page 60: Work Clamp Lifter Mechanism
12. Stepping work clamp driving lever 13. Set screw (Loosen) 14. Set screw (Loosen) 15. Screw 16. Plain washer 17. Retaining ring C 18. Work clamp fulcrum shaft 19. Work clamp cam gear 20. Ball bearings [2 pcs] 1256B BAS-342G...
Page 61: Tension Release Mechanism
5111Q 5-12. Intermittent presser foot lifter mechanism (2) 1. Bolts [2 pcs] 2. Stepping clamp lifter rod holder 3. Flat screw 4. Set screw (Loosen) 5. Stepping clamp lifter shaft (Pull out) 1257B 6. Stepping clamp lifter (Pull forward) BAS-342G...
Page 62: Thread Trimmer Mechanism
29. Thread trimmer collar 8. Solenoid lever 20. Guide shaft 30. Screws [2 pcs] 9. Washer 21. Compression spring 31. Flat screws [2 pcs] 10. Solenoid cushion 22. Cushion 32. Needle plate 11. Bolts [2 pcs] 12. Spring washers [2 pcs] BAS-342G...
Page 63: Shuttle Hook Mechanism
68. Thread trimmer rod H 47. Plain washer 48. Nut 49. Shoulder screw B 5-14. Shuttle hook mechanism 1318B 1. Bobbin case assembly 2. Shuttle race base setting claw （Open to right and left） 3. Shuttle race base 4. Shuttle hook BAS-342G...
Page 64: Assembly
Apply grease to the required places when reassembling the parts and once every two years. 6-1. Thread trimmer mechanism (1) Apply the grease <SA8837-001> specified by Brother in the places indicated by When the ball joint assembly of the thread trimmer...
Page 65 32. Set screw 49. Shoulder screw B 33. Thread trimmer solenoid 50. Nut 34. Solenoid bracket 51. Plain washer 35. Plain washers [2 pcs] 52. Spring washer 36. Spring washers [2 pcs] 53. Bolt 37. Bolts [2 pcs] 4615Q BAS-342G...
Page 66: Intermittent Presser Foot Lifter Mechanism (1)
10. Bolt 11. Plain washers [2 pcs] 12. Spring washers [2 pcs] 13. Bolts [2 pcs] 14. Solenoid cover 15. O rings [2 pcs] 16. Shoulder screws [2 pcs] 17. Tension release pin 18. Tension bracket 19. Set screw 5139Q BAS-342G...
Page 67: Work Clamp Lifter Mechanism
6. ASSEMBLY 6-4. Work clamp lifter mechanism Apply the grease <SA8837-001> specified by Brother in the places indicated by Set the work clamp cam gear (2) so that there is no clearance between it and the ball bearing in the shaft...
Page 68 Align the index marks on the work clamp cam gear and the work clamp driving gear, and then install the work clamp motor plate (20) with the two bolts (22) so that there is no backlash. BAS-342G...
Page 69: Feed Mechanism
6. ASSEMBLY 6-5. Feed mechanism 6-5-1. Y-feed mechanism Apply the grease <SA8837-001> specified by Brother in the places indicated by 1. Y-pulley brackets [2 pcs] 2. Y-GT belts [2 pcs] 3. Pulley fulcrum shafts [2 pcs] 4. Pulley fulcrum shaft collars [2 pcs] 5.
Page 70 24. Y motor bracket 25. Bolts [4 pcs] 26. Bolts with washers [4 pcs] (Temporarily tighten) 27. Fan 28. Screws [4 pcs] 29. Fan bracket 30. Bolts [2 pcs] Apply grease to the holes and grooves of the Y motor shaft. 1282B BAS-342G...
Page 71 36. Bolts M6X35 [2 pcs] (Remove) and then pull the Y pulley bracket assembly (c) to adjust the belt tension. * After adjusting the belt tension, measure the tension. (Refer to the next page.) (Continued on the next page.) BAS-342G...
Page 72 * The belt tension gauge should be set to measure a unit weight of 0.04 kg/m, a belt width of 50 mm and a span length of 333 mm. * It is recommended that you use the Yunitta U-505 tension gauge. BAS-342G...
Page 73 Y motor so that the index mark on the end of the Y motor shaft is facing directly upward. Center of needle hole Center Y direction 1287B BAS-342G...
Page 74: X-Feed Mechanism
6. ASSEMBLY 6-5-2. X-feed mechanism Apply the grease <SA8837-001> specified by Brother in the place indicated by 1. X pulley bracket 2. X-GT belt 3. Pulley fulcrum shaft 4. Pulley fulcrum shaft collar 5. Pulley A assembly 6. Set screws [2 pcs]...
Page 75 Edge Install the Y base plate tool (21) so that its edges are positioned as shown in the illustration. 1292B Edge Edge * Once installation is complete, remove the Y base plate tool (21). (Continued on the next page.) BAS-342G...
Page 76 Install the X motor assembly Center of (29) so that the projection is needle hole touching against the bed. Center X direction 1294B Index mark Adjust and install so that the backlash is within 0.01 to 0.05. 1295B BAS-342G...
Page 77 Y pulley bracket 37. Bolts with washers [2 pcs] (Fully tighten) assembly (d) to adjust the 38. Bolts M6X30 (Remove) belt tension. * After adjusting the belt tension, measure the tension. (Refer to the next page.) (Continued on the next page.) BAS-342G...
Page 78 * The belt tension gauge should be set to measure a unit weight of 0.04 kg/m, a belt width of 50 mm and a span length of 485 * It is recommended that you use the Yunitta U-505 tension gauge. BAS-342G...
Page 79: Feed Covers
10. Screws 4X8 [3 pcs] 11. Inside cover L assembly 12. Screws 4X8 [3 pcs] 13. Bellow assembly 14. Screws [4 pcs] (Tighten the inside cover R assembly and inside cover L assembly together.) 1300B (Continued on the next page.) BAS-342G...
Page 80 Install the support plate bracket so that the notches are aligned with 1302B the edge of the bed. 15. Auxiliary plate 16. Bolts with washers [14 pcs] Support plate bracket 1303B After installing, check that the height of the needle plate is as shown in the illustration. Needle plate 1304B BAS-342G...
Page 81: Upper Shaft Mechanism
6. ASSEMBLY 6-7. Upper shaft mechanism Before inserting the upper shaft (1), apply the grease <SA8837-001> specified by Brother to the places indicated by Apply adhesive <Threebond 1324> to the outer circumference of the joint assembly bearing. 1305B Install the driving wheel B-winder so...
Page 82 15. Motor assembly thread trimmer cam position". 16. Bolts [4 pcs] 17. Fries wheels [2 pcs] Apply the grease <SA8837-001> specified by Brother to 18. Screws [3 pcs] the groove. 19. Set screws [2 pcs] 20. Set screws [2 pcs] 21.
Page 83: Needle Bar Mechanism
6. ASSEMBLY 6-8. Needle bar mechanism Apply the grease <SA8837-001> specified by Brother in the places indicated by Set so that this hole faces vertically, then push gently while tightening the set screws (14) to install. Inside hole 5142Q Left-hand thread...
Page 84 4647Q BAS-342G...
Page 85: Intermittent Presser Foot Lifter Mechanism (2)
B (or Tighten the set screw on the screw stop b) on the needle bar is while lightly pressing the link shaft. aligned with the lower edge of the needle bar bush A 1428B (Continued on the next page.) 1307B BAS-342G...
Page 86 Turn the work clamp cam gear (1) to move the stepping work clamp driving lever (2) to the dotted line position shown in the illustration. Set the needle bar to the timing position Loosen the nut (10) and turn the bolt (11) to set the height of the intermittent presser foot (7) to 0.5 mm above the needle plate. BAS-342G...
Page 87: Lower Shaft Mechanism
8. Set screw collar B 9. Set screws [2 pcs] 10. Pinch sleeve B 11. Bolt (Temporarily tighten) 12. Set screw collar R 13. Set screw (Temporarily tighten) 14. Set screws [2 pcs] (Temporarily tighten) (Continued on the next page.) BAS-342G...
Page 88 26. Driver 27. Bolt (Temporarily tighten) 28. Crank rod [Lower part] (Insert into upper shaft crank) 29. Needle bearing 30. Crank rod [Upper part] (Align the mating mark) 31. Bolts [2 pcs] 32. Crank cover 33. Screws [3 pcs] 1312B BAS-342G...
Page 89: Shuttle Hook Mechanism
6. Shuttle race base setting claw (Close) 7. Bobbin 8. Bobbin case 6-12. Thread trimmer mechanism (2) Apply the grease <SA8837-001> specified by Brother in the places indicated by 5151Q Movable knife connecting plate 1. Fixed knife 1314B 2. Plain washers [2 pcs] 3.
Page 90: Work Clamp Arm Mechanism
If the needle hole goes outside the frames, adjust the position of the feed plate or readjust the home position. BAS-342G...
Page 91: Adjusting The Lift Of The Work Clamp Arm Assembly
3. Tighten the four set screws (13) so that the pressure is uniform at the front and back of the work clamp (6), and then tighten the four nuts (12). (Reference dimension: When the edge of the work clamp (6) is 26 mm above the top of the needle plate) 4. Tighten the four nuts (11). BAS-342G...
Page 92: Thread Wiper Mechanism
2. Bolts with washers [2 pcs] 3. Bolt (Remove) 4. Plain washer (Remove) 5. Removed plain washer 6. Removed bolt 7. STOP switch harness 8. Thread wiper solenoid harness Adjust the thread wiper after installing. (Refer to “7-11. Adjusting the thread wiper”.) BAS-342G...
Page 93: Covers
6. ASSEMBLY 6-15. Covers 1316B 1. Shuttle race cover assembly 2. Face plate 3. Eye guard 4. Rear cover FL 5. Rear cover FR 6. Rear cover 7. X motor cover 8. Motor cover 9. Top cover BAS-342G...
Page 94: Adjustment
In addition, do not subject the machine head to extra Ask your Brother dealer or a qualified electrician to force while it is tilted back. If this is not observed, the carry out any maintenance and inspection of the machine head may become unbalanced and fall electrical system.
Page 95: Standard Thread Tension
0.3 − 0.4 Lower thread tension (N) Thread take-up spring height 7 − 10 (mm) Thread take-up spring 0.6 − 1.2 tension (N) 0.2 − 0.4 Pre-tension (N) Needle DP x 17 #19 7-2-1. Upper and lower thread tension 1378B 1377B BAS-342G...
Page 96: Thread Take-Up Spring
* When sewing heavy material, move arm thread guide R (1) to the left. (The thread take-up amount will become greater.) * When sewing light material, move arm thread guide R (1) to the right. (The thread take-up amount will become less.) Index mark Index mark 4031M BAS-342G...
Page 97: Adjusting The Needle Bar Height
If it crosses the needle more than necessary, it will place a load on the needle, or it may cause poor thread tension. Furthermore, if it does not cross the needle at all, the tip of the rotary hook will interfere with the needle and skipped stitches may occur. BAS-342G...
Page 98: Adjusting The Needle Clearance
If the shuttle race thread guide (1) is in the wrong position, thread breakages, soiled thread or tangling of the thread may occur. The position of the shuttle race thread guide (1) is adjusted at the time of shipment from the factory. It should not be changed if possible. BAS-342G...
Page 99: Adjusting The Rotary Hook Lubrication Amount
Less oil • If the position of the sub-tank (4) is lowered, the lubrication amount will decrease. 5. Return the machine head to its original position. 6. Install the X motor cover (2) with the four screws (1). 4038M BAS-342G...
Page 100: Adjusting The Position Of The Movable Knife
6. Move the movable knife connecting plate (10) back and forth to adjust so that the distance from the ridge on the right side of the needle plate to the ridge on the movable knife (9) is 9.5 to 9.9 mm. 7. After tightening the bolt (8), check the above position once more. BAS-342G...
Page 101 11. Check that there is a gap of about 0 - 1 mm between the outside of the hole in the movable knife (9) and the ridge line on the shuttle race thread guide (13) when there is still play between the parts. BAS-342G...
Page 102: Replacing The Movable And Fixed Knives
7. Apply grease to the pin (12), place it into the movable knife connecting plate (13), and install it to the needle plate (5). 8. Check that the needle is aligned with the center of the needle hole. 9. Install the feed plate (2). (Refer to the next page.) BAS-342G...
Page 103: Installing The Feed Plate
2 mm and the tip of the thread wiper (2) is approximately 3 mm from the center of the needle when the thread wiper (2) passes below the needle during operation. NOTE: Check that the thread wiper (2) does not touch the finger guard (6). BAS-342G...
Page 104: Presser Foot Installation Position
(Refer to the next page.) Installation position Intermittent stroke range 2 − 4.5mm 4.5 − 10mm 0 mm (Presser foot does not move up and down) 5012Q BAS-342G...
Page 105 <If they are touching> Remove the motor cover (4). Loosen the nut (5), and turn the bolt (6) until it is pressing against the intermittent drive lever (7), and then adjust until the two points mentioned above are not touching. BAS-342G...
Page 106: Adjusting The Work Clamp Lift Amount
7-15. Adjusting the air pressure Lift up the handle (2) of the regulator (1) and then turn it to adjust the air pressure to 0.5 MPa. After adjustment is complete, push the handle (2) downward to lock it. 3975M BAS-342G...
Page 107: Adjusting The Thread Trimmer Cam Position
* The belt tension gauge should be set to measure a unit weight of 0.04 kg/m, a belt width of 50 mm and a span length of 485 mm. * It is recommended that you use the Yunitta U-505 tension gauge. BAS-342G...
Page 108 * The belt tension gauge should be set to measure a unit weight of 0.04 kg/m, a belt width of 50 mm and a span length of 333 mm. * It is recommended that you use the Yunitta U-505 tension gauge. BAS-342G...
Page 109: Adjusting The Tension Release Amount
If memory switch No. 552 has been set so that the tension release timing is early, you can increase the trailing length for the upper thread. BAS-342G...
Page 110: Adjusting The Lower Shaft Gear Backlash
1. Remove the two screws (1), and then remove the motor cover (2). 2. Remove the sixteen screws (3), and then remove the rear cover (4). 3. Remove the two screws (5), and then remove the Y motor fan (6). 4. Gently tilt back the machine head. BAS-342G...
Page 111 (10). 7. Turn the rock gear shaft (12) to adjust the tip of the driver (13) so that there is 0.05 to 0.15 mm of play, and then tighten the two set screws (7) and the bolt (8). BAS-342G...
Page 112: Adjusting The Home Position
Always be sure to press the RESET key and check that the index marks are aligned with the center line before ending adjustment mode. If you end adjustment mode without checking the home position, error "E303" may be generated. BAS-342G...
Page 113: X-Y Feed Home Position
• Home position detection will be carried out, and the work clamp will stop at the currently-registered home position. * If you press the RESET key for 2 seconds or more at this time, the offset value will be reset to “ 0 ”. (Continued on the next page) BAS-342G...
Page 114 TEST indicator switches off NOTE: Be sure to press the RESET key to check the home position before ending adjustment mode. If adjustment mode is ended without checking the home position, error “E202” will be generated. BAS-342G...
Page 115: Adjusting The Needle Up Stop Home Position
11. Turn the pulley to move the needle bar (4) to the position plate of H and check that the menu display switches from “ Needle DP x 17 DP x 5 on” to “ oFF” Distance H 55.5 mm 50.4 mm Distance h 18.0 mm 12.9 mm 1420B BAS-342G...
Page 116: Adjusting The Needle Up Stop Position
X-Y feed home position detection will be carried out, and then “orG” will stop flashing and illuminate steadily. Start switch 1385B Depress the start switch once more. ・ The upper shaft will operate and the needle bar will stop at the needle up stop position. Start switch BAS-342G...
Page 117: Bas-342G
The upper shaft will operate and stop at the offset value which has been set. Start switch 1385B End adjustment mode Press the TEST key. ・ The changes to the offset value will be memorized and the sewing machine will switch to home position detection standby. TEST indicator switches off BAS-342G...
Page 118: Electrical Mechanism
The fan inside the control box turns while the power is turned on, so be careful not to get anything caught in it. Be careful not to touch metallic objects such as the heat sink and cover when connecting and disconnecting connectors and making measurements. BAS-342G...
Page 119: Inside The Control Box And Operation Panel Structure
Secured to the inside of the operation panel. This P.C. board is used for displaying the sewing machine status and for input operations. Control box Operation panel DC fan motor Panel P.C. board NF P.C. board Power supply motor P.C. board Main P.C. board Conversion PMD P.C. board transformer 1407B 5071Q BAS-342G...
Page 120: Description Of Fuses
Fuse 3AFB DC fan motor does not operate and [E740] is 616167-001 (Glass tube fuse 3A-250V) displayed. Fuse 15AFB Power indicator does not illuminate and nothing SA3794-001 (Glass tube fuse 15A-250V) operates. Power supply motor P.C. board 4590Q BAS-342G...
Page 121: Description Of Connectors
A large number of problems are often caused by connectors that are not inserted correctly or which are contacting poorly. As a result, check that all connectors are inserted correctly and that the pins and wires are crimped properly before carrying out problem diagnosis. 8-4-1. Connector positions Main P.C. board 5072Q BAS-342G...
Page 122 8. ELECTRICAL MECHANISM PMD P.C. board 1260B Power supply motor P.C. board 4593Q BAS-342G...
Page 123 8. ELECTRICAL MECHANISM Panel P.C. board 4594Q BAS-342G...
Page 124: Symptoms When There Are Poor Connections
Trouble symptom Connector No. and position • The work clamp pulse motor operates, but the home position is not detected correctly. • [E300] is displayed. 5242Q • The work clamp pulse motor does not operate. • [E300] is displayed. 4712Q BAS-342G...
Page 125 Connector No. and position • Power indicator does not illuminate and sewing machine does not operate. • Operation is unstable. 5244Q • [E403] is displayed when the power is turned on and the sewing machine does not start. 4717Q BAS-342G...
Page 126 • Operation panel keys do not work. 5246Q • Sewing machine does not start when foot switch is depressed. Work clamp is lowered when work clamp switch (left) is depressed. Home position is detected and sewing machine starts when start switch (right) is depressed. 5247Q BAS-342G...
Page 127 8. ELECTRICAL MECHANISM • After the power is turned on, [E055] is displayed. 5248Q • After the power is turned on, [E452] is displayed. 5249Q BAS-342G...
Page 128: Troubleshooting
Refer to “8-5-3. Remedy” for the item that corresponds to the problem #. Carry out the Remedy inspections for the problems in the order of the numbers in the “Cause” column. NOTE: When replacing the fuses, be sure to use a fuse with the same material and rating. BAS-342G...
Page 129: Diagnosis Flowchart
8. ELECTRICAL MECHANISM 8-5-2. Diagnosis flowchart Description of symbols Setting and status Continued on Switch operation previous/next page Judgment Power switch OFF “Problem” symbol in the “8-5-3. Remedy” lists 1429B BAS-342G...
Page 130 8. ELECTRICAL MECHANISM 1424B BAS-342G...
Page 131 8. ELECTRICAL MECHANISM 1425B BAS-342G...
Page 132 8. ELECTRICAL MECHANISM 1426B BAS-342G...
Page 133: Remedy
2） OK if there is continuity between pins 1-2, 3-4 and 5-6 of the 6-pin connector coming out from the transformer. [Fig. B] 3） OK if there is continuity between pins 3-4 and 6-7 of the 7-pin connector coming out from the transformer. 1319B [Fig. C] 1266B 1426B BAS-342G...
Page 134 After measuring, turn off the power. 5085Q 7. Malfunction of panel P.C. board Check that connector P1 (PANEL) is inserted into Panel P.C. board the main P.C. board, and that connector CN2 Panel harness (MAIN) is inserted into the panel P.C. board. BAS-342G...
Page 135 (for X motor or Y motor) 2） Check that connector P10 (SENSOR2) is the X motor. inserted into the main P.C. board. If [E742] is displayed, there is a malfunction of the cooling fan for the Y motor. BAS-342G...
Page 136 Start clamp 1201B Problem #6 Home position is incorrect. Replacement if a Cause Inspection/Remedy/Adjustment malfunction Incorrect home position adjustment Switch to adjustment mode and adjust the X and Y feed home positions. (Refer to “7-20. Adjusting the home position”.) BAS-342G...
Page 137 2） Check the Y home position sensor input while referring to “2-7. Input checking method”. 3） If a metallic object is brought close to the Y home position sensor and the LED inside the sensor does not illuminate, there is a malfunction of the sensor. BAS-342G...
Page 138 1-2 of the cord-side connector. OK if approx. +16 V After measuring, turn off the power, wait 5 minutes or more and then insert P2. 5） Check that connector P1 (MAIN) is inserted into the PMD P.C. board. 1267B BAS-342G...
Page 139 Cause Inspection/Remedy/Adjustment malfunction 1. Insufficient air pressure Set to an appropriate pressure while referring to “7-15. Adjusting the air pressure”. 2. Incorrect mechanism adjustment Move the air valve manually and check that the work clamp does not move stiffly. BAS-342G...
Page 140 30 minutes. operates when the sewing machine 2） Turn the power back on; OK if operation is is operated at short cycle. normal. Avoid repeated sewing of sewing data that is less than 15 stitches. BAS-342G...
Page 141 “6-13-1. Adjusting the lift of the work clamp arm assembly.” 3） If there is play in the feed mechanism, adjust the feed mechanism. BAS-342G...
Page 142 2） With connector P7 (SOL2) connected to the PMD P.C. board, turn on the power and carry out sewing, and measure the voltage between pins 1-2 of connector P7 (SOL2). OK if voltage is output momentarily at the sewing end. 4891Q BAS-342G...
Page 143 Power supply motor P.C. P.C. board PMD P.C. board, measure the voltage at the cord. board OK if approximately 30 V DC between pins 3-4 4892Q 5. Malfunction of main P.C. board Main P.C. board 6. Malfunction of motor Motor BAS-342G...
Page 144: Table Of Error Codes
E120 Turn off the power, and then check the synchronizer connection. Thread trimming was not completed. E121 Turn off the power, and then check if the cutting edges of the fixed knife and movable knife are damaged or worn. BAS-342G...
Page 145 Intermittent presser foot raised or lowered position cannot be detected. E301 Turn off the power, and then check if there are any problems in the intermittent presser foot vertical direction. Problem with work clamp motor home position adjustment data. E303 Re-adjust the home position. BAS-342G...
Page 146 Machine head memory is not connected. E452 Turn off the power, and then check that connector P3 on the power supply motor P.C. board is properly connected. Internal memory is full and copying is not possible. E474 Clear the sewing data. BAS-342G...
Page 147 Check that connector P10 on the main P.C. board is properly connected. If an error code that is not listed above appears or if carrying out the specified remedy does not solve the problem, contact the place of purchase. BAS-342G...
Page 148: Troubleshooting
Refer to "Skipped stitches occur". P. 140 needle. start. Instruction Upper thread trailing length is uneven. Adjust the sub-tension. manual Position of shuttle race thread guide is Adjust the position of the shuttle race P. 89 incorrect thread guide. BAS-342G...
Page 149 Needle and rotary hook timing is Adjust the needle bar lift amount. P. 88 incorrect. Shuttle race thread guide is not Adjust the position of the shuttle race P. 89 separating the threads. thread guide. BAS-342G...
Page 150 Adjust the position of the safety Instruction Safety switch does not work. depressed. switch. manual If the safety switch is malfunctioning, replace it with a new one. BAS-342G...
Page 151: Segment Display
11. 7-SEGMENT DISPLAY ０１２３４５６７８９ＡＢＣＤＥＦＧＨＩＪＫＬＭＮＯＰＱＲＳＴＵＶＷＸＹＺ BAS-342G...
Page 152 SERVICE MANUAL http://www.brother.com/ 15-1, Naeshiro-cho, Mizuho-ku, Nagoya 467-8561, Japan. Phone: 81-52-824-2177 Printed in Japan BAS-342G I7070928B 2007.09. B (1)

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