Pfaff 939 U Instruction Manual
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939 U
3704
-2/02
-2/03

Instruction Manual

This instruction manual applies to machines from the
following serial numbers onwards:
# 2660862
296-12-18 603/002
Betriebsanleitung engl. 01.05

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Summary of Contents for Pfaff 939 U

  • Page 1: Instruction Manual

    939 U 3704 -2/02 -2/03 Instruction Manual This instruction manual applies to machines from the following serial numbers onwards: # 2660862 296-12-18 603/002 Betriebsanleitung engl. 01.05...
  • Page 2 This instruction manual applies to all versions and subclasses listed under "Specifications". Reprinting, copying or translation of PFAFF instruction manuals, whether in whole or in part, is not permitted without our prior permission and not without written indication of the source.
  • Page 3: Table Of Contents

    Adjustment lever for the differential feed (only on the PFAFF 3704-2/..) ....... 7 - 6 Adjustment wheel for multi-stitch and zigzag stitch (only on the PFAFF 939 U) ... 7 - 6 Mechanical edge guide (only on the PFAFF 3704-2/02) ..........7 - 7 Knee switch (only on the PFAFF 3704-2/..) ..............
  • Page 4: Contents

    Installation ........................8 - 1 Adjusting the table height ..................... 8 - 1 Fitting the top belt guard (only on the PFAFF 939 U) ............. 8 - 2 Fitting the reel stand ..................... 8 - 2 Fitting the Quick-flange motor (only on the PFAFF 939 U) ..........8 - 3 Fit the belt guard of the Quick flange-motor.
  • Page 5 Differential feed synchronisation (only on the PFAFF 3704-2/..) ........12 - 18 05.17 Position of the stitch length adjustment wheel on the PFAFF 939 U......12 - 19 05.18 Position of the stitch length adjustment wheel on the PFAFF 3704-2/......12 - 20 05.19...
  • Page 6 05.43 Stitch condensation (only on the PFAFF 3704-2/02) ............ 12 - 45 05.44 Switching to reverse feed (only on the PFAFF 3704-2/03) .......... 12 - 46 05.45 Thread puller (only on the PFAFF 3704-2/02) ............... 12 - 47 Adjusting the thread trimmer -900/24 ................. 12 - 48 06.01...
  • Page 7: Safety

    Safety Safety Regulations This machine is constructed in accordance with the European regulations indicated in the conformity and manufacturer's declarations. In addition to this instruction manual, please also observe all generally accepted, statutory and other legal requirements, including those of the user's country, and the applicable pol- lution control regulations! The valid regulations of the regional social insurance society for occupational accidents or other supervisory authorities are to be strictly adhered to!
  • Page 8: Safety Symbols

    ● The user must ensure that none of the safety devices are removed nor put out of work- ing order. ● The user must ensure that only authorized persons operate and work on the machine. For further information please refer to your PFAFF agency. 1 - 2...
  • Page 9: Notes For Operating And Technical Staff

    Safety Notes for operating and technical staff Operating staff .05.01 Operating staff are the persons responsible for setting up, operating and cleaning the machine and for eliminating any malfunctioning in the sewing area. The operating staff is obliged to observe the following points: ●...
  • Page 10: Danger

    Safety Danger A working area of 1 meter is to be kept free both in front of and behind the machine while it is in operation so that it is always easily accessible. Never reach into the sewing area while sewing! Danger of injury by the needle! Never leave objects on the table while adjusting the machine settings! Objects can become trapped or be slung away! Danger of injury! 112-024...
  • Page 11: Proper Use

    Proper use Proper use The PFAFF 939 U is a high-speed zigzag sewing machine with differential bottom feed and mechanical shift from zigzag to 3-stitch zigzag. The machines are used for producing zigzag lockstitch seams in the clothing and linen industry.
  • Page 12: Specifications

    ▲ Specifications Stitch type: ..................304 (zigzag lockstitch) Needle system PFAFF 939 U / PFAFF 3704-2/03: .................. 438 PFAFF 3704-2/02: ..................... 134 EL Needle size in 1/100 mm: Model B: ......................... 80 - 100 Presser foot clearance: ....................7 mm Clearance width: ....................
  • Page 13: Disposal Of Machine

    Disposal of Machine Disposal of Machine ● Proper disposal of the machine is the responsibility of the customer. ● The materials used for the machine are steel, aluminium, brass and various plastic mat- erials. The electrical equipment comprises plastic materials and copper. ●...
  • Page 14: Transportation, Packing And Storage

    Transportation, packing and storage Transportation, packing and storage Transportation to customer's premises The machines are delivered completely packed. Transportation inside the customer's premises The manufacturer cannot be made liable for transportation inside the customer's premises nor to other operating locations. It must be ensured that the machines are only transported in an upright position.
  • Page 15: Explanation Of Symbols

    Explanation of symbols Explanation of symbols In this instruction manual, work to be carried out or important information is accentuated by symbols. These symbols have the following meanings: Note, information Cleaning, care Lubrication Maintenance, repairs, adjustment, service work (only to be carried out by technical staff) 6 - 1...
  • Page 16: Controls

    Controls Controls Main switch ● The machine is switched on or off by turning the main switch 1. Fig. 7 - 01 Keys on the machine head (only on machines with Quick-flange motor) ● As long as key 1 is pressed during sewing, the machine sews in reverse.
  • Page 17: Pedal On The Pfaff 939 U

    Controls Pedal on the PFAFF 939 U 0 = Resting position +1 = Lower presser foot +2 = Sew -1 = Lift presser-foot (on machines with automatic presser-foot lifter) -2 = Trim thread (on machines with a thread trimmer) 3 + (+2) = Requesting the second feed stroke value.
  • Page 18: Lever For Raising Presser Foot

    ● The presser foot is raised by turning lever 1. Fig. 7 - 05 Knee lever (only on the PFAFF 939 U) ● On machines without an automatic pres- ser foot lift, the knee lever 1 is used to raise the presser foot.
  • Page 19: Adjustment Lever For Zigzag Stitch And Needle Position

    Controls Adjustment lever for zigzag stitch and needle position ● The zigzag stitch adjustment lever 1 is used for adjusting the width of the zigzag stitch. ● To change the position of the adjustment lever, the locking lever 2 must be pressed against the adjustment lever 1.
  • Page 20: Stitch Length Adjustment Wheel

    ● Set the stitch length by turning the stitch length adjustment wheel 1. The stitch length setting can be read on scale 2. Adjustment wheels for the top feed (only on the PFAFF 939 U) ● Adjustment wheel 1 (1st setting) This adjustment wheel is for adjusting the setting with which the machine is to do most of its work.
  • Page 21: Adjustment Lever For The Differential Feed (Only On The Pfaff 3704-2

    112-050 112-005 Fig. 7 - 13 Adjustment wheel for multi-stitch and zigzag stitch (only on the PFAFF 939 U) Before sewing begins, make sure that adjustment wheel 1 is locked in position! Only switch over when the machine is at a...
  • Page 22: Mechanical Edge Guide (Only On The Pfaff 3704-2/02)

    Controls Mechanical edge guide (only on the PFAFF 3704-2/02) Switching on the edge guide: ● Press knob 1 in the direction of the arrow until it locks into place. Switching off the edge guide: ● Press down key 2. Fig. 7 - 15 Knee switch (only on the PFAFF 3704-2/..)
  • Page 23: Control Panel (Only On Machines With Quick-Eco-Drive Motor)

    The control panels switches on all LCD- segments and the horn automatically for a short time during the power-on phase, after which the lettering PFAFF appears on the display, until the higher-ranking control unit sends commands to the control panel.
  • Page 24 Controls Start backtacks ● If this key is pressed, the backtacks at the beginning of the seam (start backtacks) are switched on or off. The number of forward stitches (A) or reverse stitches (B) for the start backtacks can be changed by pressing the +/- key underneath. To convert from double backtack to single backtack set the number of stitches for the corresponding seam section at zero.
  • Page 25: Installation And Commissioning

    Installation and commissioning Installation and commissioning The machine must only be installed and commissioned by qualified personnel! All relevant safety regulations must be strictly adhered to! If the machine is delivered without a table, be sure to use a stand and table top that can hold the weight of the machine with its motor.
  • Page 26: Fitting The Top Belt Guard (Only On The Pfaff 939 U)

    Installation and commissioning Fitting the top belt guard .01.02 (only on the PFAFF 939 U) ● Slide the left and right halves of the V- belt guard into place with the slots behind the heads of screws 1 and 2.
  • Page 27: Fitting The Quick-Flange Motor (Only On The Pfaff 939 U)

    Installation and commissioning Fitting the Quick-flange motor (only on the PFAFF 939 U) Fig. 8 - 04 ● Loosen screws 1 and remove toothed belt wheel 2 from the motor shaft 3. ● Attach bearing plate 4 to the motor 5 with screws 6 as shown in Fig. 8-04.
  • Page 28: Table Top Cutout For The Pfaff 939 U

    Installation and commissioning Table top cutout for the PFAFF 939 U 8 - 4...
  • Page 29: Table Top Assembly For The Pfaff 939 U

    Installation and commissioning Table top assembly for the PFAFF 939 U 8 - 5...
  • Page 30: Connecting The Plug-In Connections And Earth Cables

    Installation and commissioning Connecting the plug-in connections and earth cables Fig. 8 - 06 ● Connect all plugs as labelled to the control box. ● Screw the earth cable from the sewing head and the main switch 1 to earth point A. ●...
  • Page 31: Commissioning

    Installation and commissioning Commissioning ● Examine the machine, in particular the electric cables and pneumatic connection tubes for any damage. ● Clean the machine thoroughly and then oil it. ● Have qualified personnel check whether the machine can be operated with the available voltage and whether it is connected properly in the terminal box.
  • Page 32: Basic Setting Of The Machine Drive Unit

    Installation and commissioning Basic setting of the machine drive unit (only on machines with Quick-Eco-Drive-Motor) ● Switch on the machine. ● Press TE/Speed key twice to call up the input mode. 101 on ● By pressing the corresponding +/- key call up parameter "798" and select value "II" (service level "C"), see Chapter 12.07.01 Selecting the user level.
  • Page 33 PFAFF 3704-2/03 PFAFF 3704-2/02 ● By pressing the corresponding +/- key enter value "70" for the PFAFF 939 U and PFAFF 3704-2/03, or value "26" for the PFAFF 3704-2/02. ● By pressing the corresponding +/- key call up parameter "703".
  • Page 34: Mounting/Connecting The Start Inhibitor (Only On Machines With Quick-Anbaumotor)

    Installation and commissioning Mounting/connecting the start inhibitor (only on machines with Quick-Anbaumotor) 92-015 Fig. 8 - 09 ● For machines delivered without a table, the plate 1 from the accessories should be mounted under the table top, so that the switch lug 2 is resting on plate 1 when the sewing head is in an upright position.
  • Page 35: Setting Up

    Setting up Setting up All instructions and regulations in this instruction manual must be observed. Special attention must be given to all safety regulations! All setting-up work must only be done by personnel with the necessary training. For all setting-up work the machine must be isolated from its power supply by turning off the on/off switch or removing the machine plug from the electric power socket! Inserting the needle...
  • Page 36: Winding The Bobbin Thread; Adjusting The Primary Thread Tension

    Setting up Winding the bobbin thread; adjusting the primary thread tension Fig. 9 - 02 ● Place an empty bobbin 1 onto bobbin winder spindle 2. ● Thread the bobbin as shown in Fig. 9 - 02 and wind it clockwise around bobbin 1 a few times.
  • Page 37: Removing/Inserting The Bobbin Case

    Setting up Removing/inserting the bobbin case Switch off the machine! Danger of injury if the machine is started accidentally! Removing the bobbin case. ● Lift clip 1 and remove bobbin case 2. Inserting the bobbin case: ● Insert bobbin case 1 until you feel it click into place.
  • Page 38: Threading The Needle Thread / Adjusting The Needle Thread Tension

    Setting up Threading the needle thread / Adjusting the needle thread tension on the PFAFF 939 U and PFAFF 3704-2/03 Fig. 9 - 05 Switch off the machine! Danger of injury if the machine is started accidentally! ● Thread the needle thread as show in the above illustration.
  • Page 39: On The Pfaff 3704-2/02

    Setting up Threading the needle thread / Adjusting the needle thread tension on the PFAFF 3704-2/02 Fig. 9 - 06 Switch off the machine! Danger of injury if the machine is started accidentally! ● Thread the needle thread as show in the above illustration.
  • Page 40: Setting The Zigzag Stitch And The Stitch Position

    Fig. 9 - 07 Adjusting the stitch length PFAFF 3704-2/.. PFAFF 939 U Fig. 9 - 08 Fig. 9 - 09 ● Adjust the stitch length by turning the feed regulator wheel 1. The setting can be read on scale 2.
  • Page 41: Adjusting The Differential Feed On The Pfaff 939 U

    Setting up Adjusting the differential feed on the PFAFF 939 U Fig. 9 - 10 Sewing without fullness .09.01 ● Turn adjustment wheel 1 as far as possible in the "+" direction. ● Turn adjustment wheel 2 until " 0 " is at marking 3.
  • Page 42: Applying Fullness Intermittently

    When the left pedal is operated, the fullness set on adjustment wheel 1 is worked into the bottom ma- terial ply (see Chapter 7.03 Pedal on the PFAFF 939 U. Constantly stretch the top material ply.
  • Page 43: Adjusting The Differential Feed On The Pfaff 3704-2

    Setting up Adjusting the differential feed on the PFAFF 3704-2/.. 112-005 Fig. 9 - 13 Fig. 9 - 12 Standard value: ● Set the value with which the machine will usually operate on lever 1. Fullness: ● Set the required deviating value (e.g. for fullness) on lever 2.
  • Page 44: Adjusting The Multi-Stitch Or The Zigzag Stitch (On The Pfaff 939 U With Quick-Flange Motor)

    Setting up Adjusting the multi-stitch or the zigzag stitch (on the PFAFF 939 U with Quick-flange motor) Changing from zigzag stitch to multi-stitch .11.01 Before sewing begins, make sure that adjustment wheel 1 is locked in position! Only switch over when the machine is at a...
  • Page 45: Entering Start And End Backtacks Or Condensed Stitches

    Darning program or Chapter 10.02 Counted seam. ● By pressing the corresponding +/- key ("A") select the desired value for the number of forward stitches (A) of the start backtack. (only on the PFAFF 939 U and the PFAFF 3704-2/03).
  • Page 46: Sewing (Only On Machines With Quick-Eco-Drive-Motoren)

    When the machine is switched on, the sewing mode is always activated. ● Switch on the machine. PFAFF 939 U; PFAFF 3704-2/03 PFAFF 3704-2/02 ● If necessary switch off the function "darning seam" or "counted seam", see Chapter 10.01 Darning program or Chapter 10.02 Counted seam.
  • Page 47: Darning Program

    Sewing Darning program 15 15 5 1 The corresponding function can be switched on or off directly with the Darning program key. The "counted seam" function is switched off automatically. Several darning programs with different seam sections A and/or B can be selected. The number of required darning programs can be selected by operating the +/- key 1.
  • Page 48: Error Messages

    For an explanation of the error codes see Chapter 12.08 Explanation of the error messages. ERROR ● Correct the error. ● Acknowledge error correction by pressing the TE/Speed key. Example of a seam on the PFAFF 3704-2/02 seam segment seam segment seam segment...
  • Page 49: Care And Maintenance

    Care and maintenance Care and maintenance Cleaning ............daily, several times by continuous operation ▲ Checking the oil level (hook oil tank) ............. once a year Checking the oil tank(zigzag eccentric lubrication) ......daily, before operation Checking/adjusting the air pressure ........daily, before each operation Cleaning the air filter/lubricator ..........
  • Page 50: Lubricating The Hook

    (see arrow in Fig. 11-03). Return the machine to its upright position with both hands. Danger of crushing between machine head and table top! We recommend PFAFF sewing machine oil. Part no. 280-1-120 105. 11 - 2...
  • Page 51: Oiling The Zigzag Drive

    ● Pour in oil until sight glass 2 is full. ● Clean the surface of cover 5, the case and the seal. ● Replace cover 5 and tighten screws 4. We recommend PFAFF sewing machine oil, part no. 280-1-120 146. 11 - 3...
  • Page 52: Cleaning The Air Filter Of The Air-Filter / Lubricator

    Care and maintenance Cleaning the air filter of the air-filter / lubricator Switch the machine off! Disconnect the air hose at the air-filter / lubricator. To drain water bowl 1: ● Water bowl 1 drains itself automatically when the compressed-air hose is disconnected from the air-filter / lubricator.
  • Page 53: Adjustment

    Adjustment Adjustment Notes on adjustment All following adjustments are based on a fully assembled machine and may only be carried out by expert staff trained for this purpose. Machine covers, which have to be removed and replaced to carry out checks and adjustments, are not mentioned in the text.
  • Page 54: Check And Adjustment Aid

    Adjustment Check and adjustment aid By blocking with holes 1 - 5 the required needle bar positions can be fixed exactly. Fig. 12 - 01 ● Turn the balance wheel until the needle bar has approximately reached the required position. ●...
  • Page 55: Adjusting The Basic Machine

    Adjustment Adjusting the basic machine Balancing weight .05.01 Requirement With the needle bar at bdc the largest eccentricity of the balancing weight 1 must be pointing upwards. Fig. 12 - 02 ● Bring the needle bar to b.d.c. ● Adjust the balance weight 1 (screw 2) in accordance with the requirement. 12 - 3...
  • Page 56: Centering The Needle In The Needle Hole (In Sewing Direction)

    Adjustment Centering the needle in the needle hole (in sewing direction) .05.02 Requirement With the zigzag setting at "0" and the needle position set at "middle" the needle must enter the center of the needle hole as viewed in the direction of sewing. Fig.
  • Page 57: Parallel Guiding Of The Needle Bar

    Adjustment Parallel guiding of the needle bar .05.03 Requirement Guide bar 5 must be parallel to the needle bar. Fig. 12 - 04 ● Bring the needle bar to tdc (hole 2). ● Loosen screws 1,2 and nut 3. ● The largest eccentricity of pin 4 must be facing downwards. ●...
  • Page 58: Locking Lever

    Adjustment Locking lever .05.04 Requirement The zigzag stitch adjustment lever 3 must be able to be locked in any position. Fig. 12 - 05 ● Loosen screw 2. ● Press locking lever 1 against the zigzag stitch adjustment lever 3. ●...
  • Page 59: Zero Stitch And Zigzag Stitch Scale

    Adjustment Zero stitch and zigzag stitch scale .05.05 Requirement With the zigzag stitch set at "0": 1. the needle bar must not move laterally when the balancewheel is turned and 2. the marking "0" on scale 1 must be at marking 2. Fig.
  • Page 60: Centering The Needle In The Needle Hole (Crosswise To Sewing Direction)

    Adjustment Centering the needle in the needle hole (crosswise to sewing direction) .05.06 Requirement With the zigzag stitch set at "0" and the needle position setting at "middle" the needle must enter the center of the needle hole as seen across the direction of sewing. Fig.
  • Page 61: Zigzag Stitch Width

    Adjustment Zigzag stitch width .05.07 Requirement At the largest zigzag stitch setting, marking 1 must be at the largest zigzag value on scale 2. Fig. 12 - 08 ● Turn the zigzag stitch adjustment lever 3 in accordance with the requirement. ●...
  • Page 62: Multi-Stitch Movement (Only On The Pfaff 939 U)

    Adjustment Multi-stitch movement .05.08 (only on the PFAFF 939 U) Requirement 1. When the needle, at its b.d.c., penetrates on the right-hand side, the recess 5 on the control cam 3 should be positioned horizontally towards the rear. 2. The lateral movement of the needle bar should have been completed when the needle penetrates the workpiece (carry out a check with the largest zigzag setting).
  • Page 63: Zigzag Stitch Movement (Only On The Pfaff 3704-2

    Adjustment Zigzag stitch movement .05.09 (only on the PFAFF 3704-2/..) Requirement When the needle bar, on the right of its throw, is positioned at t.d.c. (adjustment hole "2"), the needle bar should not move laterally when the zigzag stitch adjustment lever is moved to and fro.
  • Page 64: Needle Penetration Symmetry (Only On The Pfaff 3704-2

    Adjustment Needle penetration symmetry .05.10 (only on the PFAFF 3704-2/..) Requirement When the zigzag stitch is set at "0", the needle should penetrate in the centre of the needle hole. With the maximum zigzag stitch set, the needle should penetrate on the left and right at the same distance from the centre hole.
  • Page 65: Zigzag Movement (Only On The Pfaff 939 U)

    Adjustment Zigzag movement .05.11 (only on the PFAFF 939 U) Requirement When the needle bar, moving from its right b.d.c., reaches its t.d.c. (hole 2), it should not carry out any lateral motion when the zigzag stitch width lever 4 is moved to and fro.
  • Page 66: Target Positioning Sensor (Only On The Pfaff 939 U)

    Adjustment Target positioning sensor .05.12 (only on the PFAFF 939 U) Requirement There should be a clearance of 0.2 – 0.3 mm between sensor 1 and control cam 3. Fig. 12 - 13 ● Adjust sensor 1 (screws 2) in accordance with the requirement.
  • Page 67: Needle Position Adjustment Lever

    Adjustment Needle position adjustment lever .05.13 Requirement The left and right throws of the needle must be the same size at the largest zigzag stitch setting and at the left or right needle position. Fig. 12 - 14 ● Loosen screws 1 and 2. ●...
  • Page 68: Adjustment Wheels For Differential Feed (Only On The Pfaff 939 U)

    Adjustment Adjustment wheels for differential feed .05.14 (only on the PFAFF 939 U) Requirement With guide pin 3 in the middle of the connecting link and the ends of the toothed racks 4 flush with each other, the zero markings on the adjustment wheels 5 must be at marking 6.
  • Page 69: Zeroing The Differentiatio (Only On The Pfaff 939 U)

    Adjustment Zeroing the differentiatio .05.15 (only on the PFAFF 939 U) Requirement With the largest stitch length set, the reverse feed control key 12 should be set at its highest position. In addition the stop lug 11 of clamp crank 8 should be touching the top regulating shaft.
  • Page 70: Differential Feed Synchronisation (Only On The Pfaff 3704-2

    Adjustment Differential feed synchronisation (only on the PFAFF 3704-2/..) .05.16 Requirement When the stitch length is set at "1.5" and both levers 1 are in the "0" position, the two feed dogs 5 should move the same distance when the balance wheel is turned.
  • Page 71: Position Of The Stitch Length Adjustment Wheel On The Pfaff 939 U

    Adjustment Position of the stitch length adjustment wheel on the PFAFF 939 U. .05.17 Requirement When adjustment wheel 3 is turned as far forward as possible, the pointer 4 should be positioned exactly opposite the mark "0" on scale 5.
  • Page 72: Position Of The Stitch Length Adjustment Wheel On The Pfaff 3704-2

    Adjustment Position of the stitch length adjustment wheel on the PFAFF 3704-2/.. .05.18 Requirement When adjustment wheel 1 is turned as far forward as possible, the marking for "0" on adjustment wheel 1 and the marking on the reverse feed control should match.
  • Page 73: Zeroing The Main Feed (Rear Feed Dog) On The Pfaff 939 U

    Adjustment Zeroing the main feed (rear feed dog) .05.19 on the PFAFF 939 U Requirement With the stitch length set at "0", when the balance wheel is turned, there should be no feeding motion of the main feed dog. Fig. 12 - 20 ●...
  • Page 74: Zeroing The Main Feed (Rear Feed Dog) On The Pfaff 3704-2

    Adjustment Zeroing the main feed (rear feed dog) .05.20 on the PFAFF 3704-2/.. Requirement With the stitch length set at "0", when the balance wheel is turned, there should be no feeding motion of the main feed dog. Fig. 12 - 21 ●...
  • Page 75: Zeroing The Differential Feed (Front Feed Dog) On The Pfaff 939 U

    Adjustment Zeroing the differential feed (front feed dog) .05.21 on the PFAFF 939 U Requirement With the stitch length set at "0" and the adjustment wheels set at "0", when the balance wheel is turned, there should be no feeding motion of the differential feed dog.
  • Page 76: Zeroing The Differential Feed (Front Feed Dog) On The Pfaff 3704-2

    Adjustment Zeroing the differential feed (front feed dog) .05.22 on the PFAFF 3704-2/.. Requirement When the stitch length is set at "0" and both levers 1 set at the "0" position, the differential feed dog 4 should not make any feeding movement when the balance wheel is turned.
  • Page 77: Torsion Spring Of The Reverse Feed Lever On The Pfaff 939 U

    Adjustment Torsion spring of the reverse feed lever .05.23 on the PFAFF 939 U Requirement With the presser foot raised, the longest stitch length set and the adjustment wheels 4 at "0", the reverse feed lever 5 must return automatically to its uppermost point after being activated.
  • Page 78: Torsion Spring Of The Reverse Feed Lever On The Pfaff 3704-2

    Adjustment Torsion spring of the reverse feed lever .05.24 on the PFAFF 3704-2/.. Requirement With the presser foot raised, the longest stitch length set and the adjustment lever 4 at "0", the reverse feed lever 5 must return automatically to its uppermost point after being activated.
  • Page 79: Torsion Spring Of The Differentiation Regulating Shaft On The Pfaff 939 U

    Adjustment Torsion spring of the differentiation regulating shaft .05.25 on the PFAFF 939 U Requirement With the presser foot raised, the stitch length set at "0", adjustment wheel 4 at + 4.5 and adjustment wheel 5 at "0", guide pin 6 must be touching in connecting link 7.
  • Page 80: Torsion Spring Of The Differentiation Regulating Shaft On The Pfaff 3704-2

    Adjustment Torsion spring of the differentiation regulating shaft .05.26 on the PFAFF 3704-2/.. Requirement When the presser foot is raised, the maximum stitch length set, lever 4 raised to its top position and lever 5 set at "0", the pointer 6 should be touching lever 4.
  • Page 81: Feeding Motion Of The Main And Differential Feeds

    Adjustment Feeding motion of the main and differential feeds .05.27 Requirement With the maximum stitch length set and the needle bar positioned 1.0 after t.d.c. (hole 4), when the reverse stitch key is operated, there should be no feeding motion of the main and differential feed dogs.
  • Page 82: Lifting Stroke Of The Main And Differential Feed Dogs

    Adjustment Lifting stroke of the main and differential feed dogs .05.28 Requirement With the stitch length set at "0" and the needle bar positioned at 0.25 after t.d.c. (hole 3), the feed dogs should be at the top of their stroke. Fig.
  • Page 83: Height Of The Main And Differential Feed Dogs

    Adjustment Height of the main and differential feed dogs .05.29 Requirement With the stitch length set at "0" and the needle bar positioned at 0.25 after t.d.c. (hole 3): 1. The feed dogs should be in the centre of the needle plate cutout and be touching the feed dog height adjustment gauge over their whole length.
  • Page 84: Drive Belt In The Gearbox Housing

    Adjustment Drive belt in the gearbox housing .05.30 Requirement Drive belt 4 must be tightened so that the machine runs freely and the belt sprockets do not have any noticeable play. Fig. 12 - 31 ● Adjust eccentric bearing bush 1 (screw 2) in accordance with the requirement and so that drive belt 4 is in the centre of bobbin opener drive wheel 3.
  • Page 85: Hook Bearing Bracket

    Adjustment Hook bearing bracket .05.31 Requirement The hook shaft must be touching the hook bearing bracket adjustment gauge 1 at the top and the side. 438 - 439 Fig. 12 - 32 ● Loosen screw 3. ● Swing the bobbin case opener to the right and remove the hook. ●...
  • Page 86: Hook Lubrication

    Adjustment Hook lubrication .05.32 Requirement When the machine is running at full speed, after about 10 seconds a fine oil streak should be visible on a strip of paper held over the needle plate cutout. Fig. 12 - 33 ● Adjust screw 1 in accordance with the requirement. 12 - 34...
  • Page 87: Pre-Adjusting The Needle Height

    Adjustment Pre-adjusting the needle height .05.33 Requirement With the needle bar at tdc (hole 2) the distance between the point of the needle and the needle plate must be 19 mm. 19 mm Fig. 12 - 34 ● Without turning it, adjust the needle bar (screws 1) in accordance with the requirement. 12 - 35...
  • Page 88: Needle Rise, Hook-To-Needle Clearance And Bobbin Case Positioning-Finger

    Adjustment Needle rise, hook-to-needle clearance and bobbin case positioning-finger .05.34 Requirement 1. With the needle position set at "middle", the zigzag stitch setting at "0" and the needle bar position 2.0 past bdc (hole 1) the hook point must be in the middle of the needle and the distance between the needle and the hook point must be 0.05 - 0.1 mm.
  • Page 89: Final Adjustment Of The Needle Height

    Adjustment Final adjustment of the needle height .05.35 Requirement With the zigzag stitch set at "0", the needle position set at "left" and the hook point in the middle of the needle, the top edge of the needle eye must be 0.5 mm underneath the hook point.
  • Page 90: Bobbin Case Opener Position

    Adjustment Bobbin case opener position .05.36 Requirement 1. There must be a clearance of 0.5 mm between the top edge of the bobbin case opener and the inner edge of the bottom section of the bobbin case. 2. Between the bobbin case opener finger and the bottom section of the bobbin case opener there must be a clearance of 0.8 mm.
  • Page 91: Bobbin Case Opener Motion

    Adjustment Bobbin case opener motion .05.37 Requirement With the needle bar 2.0 past bdc (hole 1) the bobbin case opener 3 must be at its right point of reversal. Fig. 12 - 38 ● Adjust bobbin opener eccentric 1 (screws 2) in accordance with the requirement. 12 - 39...
  • Page 92: Presser Foot To Needle Plate Clearance / Presser Foot Pressure

    Adjustment Presser foot to needle plate clearance / Presser foot pressure .05.38 Requirement 1. When the hand lever is raised, the needle should penetrate exactly in the "needle hole centre" of the presser foot and the presser foot to needle plate clearance should be 5 mm. 2.
  • Page 93: Thread Diverter Pin

    Adjustment Thread diverter pin .05.39 Requirement With the needle bar at bdc the top edge of the thread guide hole must be at the same height as the bottom edge of the thread diverter. Fig. 12 - 40 ● Adjust thread guide bar 1 (screw 2) according to the requirement, taking care that it is parallel to the bed-plate.
  • Page 94: Limiting The Knee Lever Stroke

    Adjustment Limiting the knee lever stroke .05.40 Requirement When the knee lever is pressed the hand lever must drop automatically and the presser foot must be just over 7 mm above the needle plate. Fig. 12 - 41 ● Place the feed dog gauge under the presser foot with its recess facing downwards. ●...
  • Page 95: Knee Lever Play

    Adjustment Knee lever play .05.41 Requirement When lightly pressing the knee lever there should be a noticeable play between nut 1 and fork 3. Fig. 12 - 42 ● Adjust nut 1 (nut 2) in accordance with the requirement and lock it with nut 2. 12 - 43...
  • Page 96: Bobbin Winder

    Adjustment Bobbin winder .05.42 Requirement 1. With the bobbin winder engaged the bobbin winder spindle must be turned reliably, but friction wheel 3 must not touch drive wheel 1 when the bobbin winder is switched off. 2. The bobbin winder must disengage automatically when the thread is approx. 1 mm from the edge of the bobbin.
  • Page 97: Stitch Condensation (Only On The Pfaff 3704-2/02)

    Adjustment Stitch condensation .05.43 (only on the PFAFF 3704-2/02) Requirement When the stitch condensation function is switched on, the feed stroke of the main and dif- ferential feed dog should be 0.2 – 0.3 mm. Fig. 12 - 44 ● Adjust crank 1 (screw 2) and crank 3 (screw 4) in accordance with the requirement.
  • Page 98: Switching To Reverse Feed (Only On The Pfaff 3704-2/03)

    Adjustment Switching to reverse feed .05.44 (only on the PFAFF 3704-2/03) Requirement When the reverse feed function is switched on, the actual length of the reverse stitches should correspond to the set stitch length. Fig. 12 - 45 ● Adjust crank 1 (screw 2) and crank 3 (screw 4) in accordance with the requirement.
  • Page 99: Thread Puller (Only On The Pfaff 3704-2/02)

    Adjustment Thread puller .05.45 (only on the PFAFF 3704-2/02) Requirement The thread puller should 1. draw so much thread that a secure seam start is guaranteed at all times and 2. remain in its end front position until the thread trimming operation is finished.
  • Page 100: Adjusting The Thread Trimmer -900/24

    Adjustment Adjusting the thread trimmer -900/24 Axial position of the control cam .06.01 Requirement 1. Roller 5 should be at a distance of 0.3 mm from the control cam 1. 2. Adjustment ring 3 should be touching the control cam 1. 0,3 mm 81-048 Fig.
  • Page 101: Preliminary Adjustment Of The Control Cam

    Adjustment Preliminary adjustment of the control cam .06.02 Requirement 1. In the needle rise position (hole 1) the roller lever 4 should lock into the corresponding groove of the control cam. 2. The control cam 1 should be touching adjustment ring 3. 81-049 Fig.
  • Page 102: Position Of The Thread Catcher And Cutting Test

    Adjustment Position of the thread catcher and cutting test .06.03 Requirement When the thread trimmer is in its neutral position, the edge of thread catcher 6 should be flush with the edge of the mounting plate 4. 81-100 Fig. 12 - 49 ●...
  • Page 103: Readjustment Of The Control Cam

    Adjustment Readjustment of the control cam .06.04 Requirement 1. When the end of the hook guard 3 is level with of the right edge of the bobbin case position finger 4, the thread catcher 5 should begin moving forwards. 2. The control cam 1 should be touching adjustment ring 6. 81-098 Fig.
  • Page 104: Needle Thread Tension Release

    57-05 Fig. 12 - 51 ● Unscrew the thread wiper. ● Turn nut 1 (nut 2) in accordance with the requirements. ● Screw thread wiper back into place. On the PFAFF 3704-2/02 both tension units are released. 12 - 52...
  • Page 105: Parameter Settings

    Adjustment Parameter settings Selecting the user level .07.01 ● Switch on the machine. ● Press the TE/Speed key twice to call up the input mode. ● By pressing the corresponding +/- key select the parameter group "798". ● By pressing the corresponding +/- key select the desired user level: "0"...
  • Page 106: Example Of A Parameter Input

    Adjustment Example of a parameter input .07.02 ● Switch on the machine. ● Press the TE/Speed key twice to select the input mode. 101 on ● By pressing the corresponding plus/minus key select parameter "798" and the user level "B", see Chapter 12.07.01 Selecting the user level. ●...
  • Page 107: Liste Der Parameter

    Adjustment Liste der Parameter .07.03 Control panel key tone A, B, C ON - OFF (OFF / ON) Backtack speed at beginning of seam B, C 300 - 2000 1200 Backtack speed at end of seam B, C 300 - 2000 1200 Speed display B, C ON - OFF...
  • Page 108: Explanation Of The Error Signals

    Adjustment Machine class 1 - 4 1 = 939U / 3704-2/.. Rotating direction of the motor 0 - 1 1 = 939U / 3704-2/.. Further parameters are listed in the Motor Instruction Manual. Explanation of the error signals Signal Description E001 Pedal not in neutral position E009...
  • Page 109: Reset / Cold Start

    Adjustment Reset / Cold start After selecting the reset menu, by pressing the corresponding key it is possible to delete seam parameters, delete seam programs and to carry out a cold start. ● Press and hold "+" on keys A and D and switch on the machine, see Chapter 7.01 Main switch.
  • Page 110: Internet Update Of The Machine Software

    Adjustment Internet update of the machine software The machine software can be updated with PFAFF flash programming. For this purpose the PFP boot program and the appropriate control software for the machine type must be installed on a PC. To transfer the data to the machine, the PC and the machine control unit must be connected with an appropriate null modem cable (part no.
  • Page 111: Wearing Parts

    You can order a detailed spare parts list for the complete machine under part no. 296-12-18 603. 91-100 296-25 (3x) 91-701 179-15 11-108 174-´25 939 U / 3704-2/03: System 438 3704-2/02: System 134 EL 11-108 174-15 (4x) 91-265 225-91 91-168 144-05...
  • Page 112 Wearing parts 99-137 151-45 91-171 049-05 91-171 042-05 91-168 498-15 91-700 249-15 91-168 499-05 11-180 094-15 13 - 2...
  • Page 113 91-196 281-95 Pneumatics-switch diagram Version 01.10.04 Schaltpläne PFAFF 3704 14 - 1...
  • Page 114: Circuit Diagrams

    Sewing motor Main switch Pedal set value transmitter Start inhibitor key Manual backtacking Needle position change key Single stitch key Bridge start inhibitor (only on the PFAFF 3704) RS232 interface (PC) Motor Incremental transmitter Set value transmitter Control panel S1 Inputs/outputs...
  • Page 115 91-191 477-95 Circuit diagrams Part 1 Version 05.11.03 PFAFF 939 U 14 - 3...
  • Page 116 Circuit diagrams 91-191 477-95 Version 05.11.03 Part 2 PFAFF 939 U 14 - 4...
  • Page 117 91-191 477-95 Circuit diagrams Part 3 Version 05.11.03 PFAFF 939 U 14 - 5...
  • Page 118 Circuit diagrams 91-191 487-95 Version 03.09.04 Part 1 PFAFF 3704 14 - 6...
  • Page 119 91-191 487-95 Circuit diagrams Part 2 Version 03.09.04 PFAFF 3704 14 - 7...
  • Page 120 Circuit diagrams 91-191 487-95 Version 03.09.04 Part 3 PFAFF 3704 14 - 8...
  • Page 121 Notes...
  • Page 122 PFAFF Industrie Maschinen AG Postfach 3020 D-67653 Kaiserslautern Königstr. 154 D-67655 Kaiserslautern Telefon: (0631) 200-0 Telefax: (0631) 17202 E-Mail: info@pfaff-industrial.com Gedruckt in der BRD Printed in Germany Imprimé en R.F.A. Impreso en la R.F.A.

This manual is also suitable for:

3704-2/023704-2/03

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