Husqvarna 6690 Manual
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Husqvarna 6690 Manual

Service-routine
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SERVICE-ROUTINE
6690
Husqvarna
1

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  • Page 1 SERVICE-ROUTINE 6690 Husqvarna...

  • Page 2: Table Of Contents

    Directions for use These service instructions are intended to be used by service workshop personnel or by salesmen who carry out servicing in their own districts themselves. They assume a thorough knowledge of the handling of precision appliances and accessibility to service tools.

  • Page 3: Visual Control Of Details

    The stitch plate The stitch plate must not be damaged in any way. Particular attention should be paid to possible damage or unevenness around the needle hole. Action Exchange the damaged stitch plate. Spare parts: See RA, page 4. Ordering No: Stitch plate: 411 5628-01. Presser foot Requirements Upper side...

  • Page 4: Bobbin Case

    The bobbin case Fabric dressing may fasten under the thread tension spring and cause the thread tension to change. This can be removed by means of a needle, which should be inserted between the spring and the bobbin case. Spare parts: See RA, page 9. Ordering No: Bobbin case 401 1530-02.

  • Page 5: Hook

    The hook Requirements The hook must not be damaged. Special attention should be given to see that the tip has not been damaged or worn, causing burrs or unevenness. Action Exchanged the damaged hook. Spare parts. See RA, page 9. Ordering No: Hook 401 1521-01.

  • Page 6: Cog Belt

    The cog belt The belt tension should not be so loose that it permits slipping when the machine is locked and the foot control is depressed. Tighter tension makes more noise. The belt should not be damaged. Adjustment The screws (14/8, 9) in the reduction gear holder are accessible by means of two holes in the large cog wheel (14/29).

  • Page 7: Reduction Gear

    The reduction gear Some change in the sound level when using the reduction gear is normal. The gear should be exchanged only if the sound deviation is very noticeable. Dismantling Set the thread take-up lever at the lowest position, remove the handwheel and then take away the belt guard, printed circuit and cog belt.

  • Page 8: Motor

    The motor Control of function The functioning of the motor can be checked without dismounting the printed circuit. Use a spare part circuit and connect it to the connections on the terminal board and test the machine in the ordinary way. The motor noise is affected by the load and the belt tension.

  • Page 9: Foot Control

    The foot control Requirements The speed should be continously controllable from r/min to full speed. The connectors to both the wall socket and the terminal borad must not be damaged or deformed. Action Test the foot control on a machine which is known to operate normally.

  • Page 10: Setting Instructions

    Setting instructions The best results will be obtained if you make the Settings in the following order at each service. Contents page Setting ratings Gauges Service tools Arm shaft. Axial play Lower shaft. Axial play Arm shaft circuit. The zig-zag movement of the needle Needle bar frame.

  • Page 11: Setting Ratings

    Setting ratings A reasonable requirement in a domestic sewing machine is that it should be able to sew all types of fabrics used in the home. The settings made when assembling and sewing-in the machines are those most suited to give the best results in the majority of fabrics and fabric combinations.

  • Page 12: Service Tools

    Service tools Box spanner To be used according to instructions on page 16. Ordering No. 411 1907-01. Adam key To be used according to instructions on pages 16 and 17. Ordering No. 411 5844-01. 3. Setting key for feeding balance. To be used according to instructions on page 43.
  • Page 13 Tool set. Ordering No. 411 1921-01 containing the following details: Flat-nose pliers with wire cutter. Ordering No. 414 4906-01. Brush with steel wire shaft Ordering No. 401 5016-01. Screwdriver with glow lamp Ordering No. 411 1904-01. Screwdriver. Wide Cl Fall Ordering No.

  • Page 14: Arm Shaft

    The arm shaft, axial play The axial bearing should enable the shaft to run freely during the whole turn and there should not be any axial play. Adjustment Set the thread take-up lever at the lowest position, remove the handwheel and then take away the belt guard.

  • Page 15: The Zig-Zag Movement Of The Needle

    The arm shaft circuit The zig-zag movement of the needle Requirements The side movement of the needle should not commenc until the needle tip is 5,5 mm above the level of the stitch plate. Check First check the height setting of the needle. See page 22.

  • Page 16: Angles To The Feeding Direction

    The needle bar frame The center position of the needle at right angles to the feeding direction. Requirements The needle shall be in the centre of the needle hole in the stitch plate. Adjustment Set the needle at the highest position. Turn on the main switch five-six times and check that the needle stops at the same position (Control of the calibration of the step motor).

  • Page 17: Feeding Direction

    The needle bar frame Setting the needle in the feeding direction. Requirements The needle should be centred in relation to the needle hole in the stitch plate. Adjustment Connect the machine and turn on the main switch, Turn the handwheel until the needle is at the same level as the stitch plate.

  • Page 18: The Stop, Needle Bar Frame

    The stop, needle bar frame Requirements The stop must not prevent the needle reaching the full zig-zag but should stop the needle from going outside the needle slot in the stitch plate. Check and adjustment Connect the machine and turn on the main switch.
  • Page 19 The gap between the hook and the needle Requirements Remove the hook cover. Connect the machine and turn on the main switch. Insert the service needle No. 411 5818-01 into the needle bar. Lay the machine on the table on its back. When the tip of the hook is in front of the centre of the needle, as shown in the illustration press the hook against the...

  • Page 20: The Timing Of The Hook In Relation To The Needle

    Setting the timing of the hook in relation to the needle Requirements Connect the machine and turn on the main switch. As the needle is moving upwards the Setting gauge 411 1752-01 tip of the hook should pass the centre of the needle when the needle is 2.5 mm above the lower turning position (the distance for formning the loop).

  • Page 21: The Gap Between The Hook Cover

    The gap between the hook cover and driver The gap between the hook cover and the driver should be such that when the hook is exchanged for the hook clearance gauge 401 1649 or 411 1635, the gauge should have no play but can be turned.

  • Page 22: The Upper Position Of The Needle

    The upper position of the needle bar Requirements When the tip of the hook passes the centre of the needle, the gap between the tip and the upper edge of the needle eye should be 1.5 mm. Comments NOTE! The gap between the tip of the hook and the The tip of the hook needle eye is influenced by the timing of the at the centre of the...

  • Page 23: The Feed Dog

    The stitch plate Requirements The stitch plate and sleeve should be firmly in place. Adjustment Remove the stitch plate and loosen the screw (4/15) which holds the arm sleeve in position. Fix the stitch plate and adjust the arm sleeve to such a position that the recess of the arm sleeve is adjusted to the stitch plate and that the arm sleeve fits into where the arm is connected to the body of the machine.

  • Page 24: The Lateral Setting Of The Feed Dog

    The feed dog setting, laterally Requirements The feed dog should move freely in the stitch plate groove. Adjustment Remove the stitch plate, Undo the screw (4/15) and remove the arm sleeve. Put back the stitch plate on the freearm. Loosen the screw (10/14) on the feed dog supporting arm and shift the supporting arm until the feed dog moves freely in the stitch plate.

  • Page 25: Lowering Of The Feed Dog

    The ratio between the setting of the feed dog and the needle (the after-feed). Press the button for straight stitching and the button for stitch length until 6,0 is indicated. Insert a piece of paper under the presser foot and turn the handwheel until the thread take-up lever is at the highest position.

  • Page 26: The Presser Bar

    The presser bar, tangential setting Requirements The presser bar should be set in such away that the needle hole in the presser foot coincides with the needle hole in the stitch plate. Adjustment The gauge 411 3161-01 for adjustment of the presser bar should be placed on the stitch plate.

  • Page 27: Thread Tension Release Lever

    The upper thread tension release Requirements The lever (6/33), which gets its impulse from the presser bar lifter, should release the pressure on the thread tension washers, via release arm (6/19), when the presser bar is lifted, but must not touch the release arm (6/19) when the presser bar is lowered.

  • Page 28: The Thread Take-Up Spring

    The thread take-up-spring Requirements The thread take-up spring (6/42) should be able to move freely in the groove of the adjustment casing and be strong enough to take up the thread. Adjustment The strength of the thread take-up spring changes if the rear part is shifted to another hole in the sleeve (6/41).

  • Page 29: The Stitch Length

    The stitch length. The balance between forward and reverse feeding when sewing buttonholes. Requirements Adjustment Both columns of the buttonhole shall be of The balance of the stitch length can be equal compactness when the fine adjusted by means of a screw, which is adjustment knobs are at neutral position.

  • Page 30: Electronic Units

    Electronic units Regarding fault-finding and checking the functioning of the electronic units, refer to “Operating Instructions for Electronics Diagnoser”, Ordering No. 104 8027-01 and “The Service Cassette”, Ordering No. 411 6503-03. Note that “Speed control”-the stop-right function” is not covered by the diagnoser. Contents page How to use the Service Cassette...

  • Page 31: How To Use The Service Cassette

    How to use the Service Cassette Summary of the checks which can be carried out when the service cassette is inserted in the front panel. Button marked Check of the capacity of the step motor to re-adjust the guide (11/15) in the feeding mechanism.

  • Page 32: Speed Control-The Stop-Right Function

    Speed control The stop-right function Driving of the motor If the machine operates when the motor is connected with a spare part circuit but not when the mounted circuit is connected, remove the faulty circuit and send it in for repair. Comment 1 Note that the brusch holder and open wiring of the motor and the rear of the printed circuit are live as soon as the...

  • Page 33: The Lowest Speed Of The Machine

    Speed control The stop-right function The lowest speed of the motor Requirements The machine should manage a lowest speed of r/min. Action Remove the wall plug. Set the thread take-up lever at the lowest position and remove the handwheel. Remove the belt guard.
  • Page 34 Setting the upper stop-right position of the needle Requirements Adjustment When the needle stops at the upper The upper stop-right position is set by moving stop-right position the clearance between the plate in the handwheel to a suitable position. the stitch plate and the needle tip should To raise the height of the needle at the upper be between 14 and 9 mm (0.55"-0.35").

  • Page 35: The Movement Of The Needle Bar Frame

    The movement of the needle bar frame (zig-zag movement). Dismounting of the step motor Remove the wiring to the step motor from the cable holder (4/37). Unscrew the screw (7/51) which holds the lamp holder in place and remove the holder. Observe the plastic protection (7/56) in the forward part.

  • Page 36: Pre-Setting Of The Step Motor

    The movement of the needle bar frame (zig-zag movement) Pre-setting of the step motor. Do not mount the step motor but connect the flat cable from the front panel, the transformer and the step motor to the circuit in the rear cover. Note that the wire of the step motor is connected to the upper outlet on the printed circuit.

  • Page 37: Mounting Of The Step Motor

    The movement of the needle bar frame (zig-zag movement) Mounting of the step motor and place the plastic bushing (11/13) on the Insert the wiring from the step motor trough stud of the segment. Hook the short spring the opening and position the step motor. (8/28) on the stud of the segment outside Tighten the short screw (11/2) to the left but the plastic bushing and on the stud of the...

  • Page 38: Arm Shaft Circuit

    Arm shaft circuit Dismounting-Mounting There are two so-called reader forks in the arm shaft circuit (7/48) for sensing the position of the arm shaft. The black disc (7/46) on the arm shaft obstructs the movement of the step motors, e.g. there can be no zig-zag movement as long as the needle is less than 5 mm above the level of the stitch plate.

  • Page 39: Dismounting Of The Step Motor

    Guiding the feeding movement Dismounting the step motor Remove the handwheel. Remove the rearcover and the belt guard, loosen the stop-right circuit (4/35) and fold it to one side. Remove the cable holder (4/37). Unscrew the hexagon support (11/47) in the shaft (11/20) for the guide (11/15). Loosen the screw (7/5) in the chain wheel (7/6) and push it towards the arm shaft circuit.

  • Page 40: Guiding Of The Feeding Movement

    Guiding of the feeding movement Pre-setting of the step motor Do not mount the step motor but connect the flat cable from the front panel, transformer and step motor to the circuit in the rear cover. Note that the wire of the step motor is connected to the lower out let on the printed circuit.

  • Page 41: Mounting Of The Step Motor

    Guiding of the feeding movement Mounting of the step motor Check that the long adjustment screw (11/31) is positioned to enable setting at both sides. Push the chain wheel (7/6), fork (7/24) and connecting rod (7/27) to the right. Thread the long adjustment screw through the large hole and out through the hole above the motor.

  • Page 42: Setting The Movement Of The Feed Dog In

    Setting the feed dog movement in relation to the needle (after-feed). Preliminary setting Loosen the stop screw (7/8) on the feeding eccentric (7/9) and turn the eccentric until the stop screw is horizontal. Hold the eccentric in place. Turn the handwheel until the take-up level is at the upper position.

  • Page 43: Setting The Balance Between Forward And Reverse Feeding

    Setting the balance between forward and reverse feeding. The screws (11/19) at the guide shaft and (11/35) under the long adjustment screw should be loose enough to permit setting at the fastening plate of the guide motor. Connect the machine and insert the service cassette.

  • Page 44: Cable Holder, Flat Cable And Printed Circuit

    Cable holder, flat cable and printed circuit. Mounting run direct to the printed circuit. Stretch the Mount the cable holder (4/37) and allow the cables to the left. Mount the step motor drive outlet to go inside the holder (4/34) for the circuit in the rear cover.

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