Singer 7258Q Service Manual
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Singer 7258Q Service Manual

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7256
7258
7258Q
Service Manual
104 73 46 01
Jan 2009

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Questions and answers

David Rudolf
March 12, 2025

Bobbin rewind does not function correctly. Slow and intermittent

1
1 comments:
Mr. Anderson
March 12, 2025

To fix a slow and intermittent bobbin rewind issue on a Singer 7258Q, follow these steps:

1. Check Bobbin Winder Shaft: Ensure the bobbin winder shaft is fully pushed to the right until it clicks into place. If it is not engaged properly, the bobbin may not wind correctly.

2. Thread Placement: Ensure the thread is correctly positioned through the tension discs of the bobbin winder. Improper threading can cause inconsistent winding.

3. Bobbin Type: Use only Class 15J bobbins, as using the wrong type can affect winding performance.

4. Clean the Bobbin Winder Area: Dust and lint buildup can cause slow winding. Clean the bobbin winder mechanism and surrounding area.

5. Check Motor Belt Tension: If the motor belt is loose, it may affect bobbin winding speed. Refer to the service manual for motor belt tension adjustments.

6. Inspect the Bobbin Winder Spring: If the bobbin does not make firm contact with the rubber wheel, the winding may be slow or inconsistent.

7. Lubrication: If the machine has been in use for a long time, check for any necessary lubrication in the bobbin winding mechanism.

If the issue persists after these steps, further inspection of the electronic components or motor may be needed.

This answer is automatically generated

0
Ken
April 25, 2025

The needle arm isn't 90 square. Its crooked...??

0
1 comments:
Mr. Anderson
May 12, 2025

To fix a crooked needle arm on a Singer 7258Q sewing machine, you need to check and adjust the needle bar height. Follow these steps:

1. Select a straight stitch at the center needle position.
2. Remove the presser foot, needle plate, and bobbin case.
3. Insert a special needle gauge (L = 29 mm) into the needle clamp.
4. Turn the hand wheel to lower the needle gauge to its lowest point.
5. Check if the bottom of the needle gauge aligns with the shuttle race.
6. If not aligned, adjust the needle bar height.

This adjustment ensures the needle arm is correctly positioned.

This answer is automatically generated

0

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Summary of Contents for Singer 7258Q

  • Page 1 7256 7258 7258Q Service Manual 104 73 46 01 Jan 2009...
  • Page 2 Original issue Service Manual January 2009 Page 2/37 Model INDEX COSMO-7/8 series 1. Disassembling of covers 2. Adjustment of feed dog height 3. Needle bar height 4. Needle threader height 5. Presser foot height and direction 6. Needle position at zigzag stitching 7.
  • Page 3 Original issue Service Manual January 2009 Page 3/37 Model COSMO-7/8 1. Disassembling of covers series (1) Face cover side Remove screw A. Remove screw B. (2) Bottom cover side Loosen seven screws.
  • Page 4 Original issue Service Manual January 2009 Page 4/37 Model COSMO-7/8 1. Disassembling of covers –continued-- series (3) Back cover side emove two self-tapping screws. emove two screws. emove self-tapping screw.
  • Page 5 Original issue Service Manual January 2009 Page 5/37 Model COSMO-7/8 1. Disassembling of covers –continued-- series (4) Front cover side Loosen screw A. Push up front cover to open inserting small screw driver between front and back covers. Open back and front covers.
  • Page 6 Original issue Service Manual January 2009 Page 6/37 Model COSMO-7/8 1. Disassembling of covers –continued-- series Pull out front cover. Open mating portion of front and back covers using small screw driver. Push back cover by small screw driver. Force front cover open by small screw driver.
  • Page 7 Original issue Service Manual January 2009 Page 7/37 Model COSMO-7/8 1. Disassembling of covers –continued-- series Force front cover open by small screw driver. Lift up front cover as below.

  • Page 8: Adjustment Of Feed Dog Height

    Original issue Service Manual January 2009 Page 8/37 Model Adjustment of feed dog height COSMO-7/8 series Checking: 1. Move feed dog to its highest position by turning hand wheel. Check to see if feed dog height is as illustrated below. 0.9 –...

  • Page 9: Needle Bar Height

    Original issue Service Manual January 2009 Page 9/37 Model COSMO-7/8 3. Needle bar height series Note: Make this checking before checking “Needle timing to shuttle” and ”Feed-dog timing (vertical motion)”. Checking: 1. Select straight stitch at center needle position. 2. Remove presser foot and needle plate, and then remove bobbin case. 3.
  • Page 10 Original issue Service Manual January 2009 Page 10/37 Model COSMO-7/8 3. Needle bar height –continued-- series 3. Tighten the screw (A) securely after adjustment. Replace needle gauge with normal needle #90/14. 4. Check to see if needle threader operates correctly and there is not interference in vertical movement of needle bar.

  • Page 11: Needle Threader Height

    COSMO-7/8 4. Needle threader height series 1. Use needle Singer 90/14. 2. Select straight stitch at center needle position. 3. Raise needle to its highest position by turning hand wheel toward you. 4. Lowering needle threader lever, check and see if hook is inserted into needle hole.
  • Page 12 Original issue Service Manual January 2009 Page 12/37 Model COSMO-7/8 4. Needle threader height --continued-- series 7. If the direction of insert hook is deviated from correct position, adjust the hook position with the small screw driver in the accessory. Needle hole Hook 8.
  • Page 13 Original issue Service Manual January 2009 Page 13/37 Model COSMO-7/8 5. Presser foot height and direction series Checking 5.6 mm 1. Lower the feed dog below the needle plate. 2. Raise the presser foot lever. 3. Check and see if clearance between the needle plate and the presser foot is about 5.6 mm.
  • Page 14 Original issue Service Manual January 2009 Page 14/37 Model COSMO-7/8 6. Needle position at zigzag stitching series Checking: 1. Select widest zigzag stitch. 2. Turn hand wheel by hand and see if needle leaves the same clearance at both right and left end of needle plate hole.

  • Page 15: Clearance Between Needle And Shuttle

    Original issue Service Manual January 2009 Page 15/37 Model COSMO-7/8 7. Clearance between needle and shuttle series Make this checking before checking “Needle timing to shuttle”. Checking: 1. Select widest zigzag stitch. 2. Remove needle plate, bobbin case and face cover. 3.
  • Page 16 Original issue Service Manual January 2009 Page 16/37 Model COSMO-7/8 7. Clearance between needle and shuttle --continued-- series 2. If needle clearance to shuttle at right and left position is not same, adjust position of fulcrum for needle swing support . Loosen bolt (A) located under bottom of support plate and adjust position of fulcrum.
  • Page 17 Original issue Service Manual January 2009 Page 17/37 Model COSMO-7/8 8. Needle timing to feed dog series Note: After adjustment, be sure to follow “Needle timing to shuttle”. As horizontal and vertical feed motion is unitized on this model, adjustment of feed timing is as follows: Checking: 1.
  • Page 18 Original issue Service Manual January 2009 Page 18/37 Model COSMO-7/8 9. Needle timing to shuttle hook series Check “Feed timing (vertical movement)” and “Needle height” beforehand. Checking 1. Select widest zigzag stitch. 2. Remove needle plate. Check to see if needle is not bent. 3.
  • Page 19 Original issue Service Manual January 2009 Page 19/37 Model COSMO-7/8 9. Needle timing to shuttle hook --continued-- series 2．Tighten screws securely after adjustment. Meshing condition of shuttle race gear and lower shaft gear 1. Check meshing condition of gear (A) after adjustment. Check play of the gear at 4 positions –each 90 degree angle of 1 rotation of shuttle race.

  • Page 20: Adjustment Of Thread Tension

    Original issue Service Manual January 2009 Page 20/37 Model COSMO-7/8 10. Adjustment of thread tension series Checking: 1. Set thread tension at the center of “AUTO” position. 2. Pull thread between tension discs and check thread tension value with two twisted Polyester #50 thread.

  • Page 21: Tension Of Timing Belt

    Original issue Service Manual January 2009 Page 21/37 Model COSMO-7/8 11. Tension of timing belt series Note: This checking is needed before and after adjusting “Needle timing to shuttle”. 1. Timing belt is engaged with gears on main and lower shafts. Too weak tension may result in slippage between shuttle gear and lower shaft gear due to thread jamming, bunching and fabric snagging.

  • Page 22: Motor Belt Tension

    Original issue Service Manual January 2009 Page 22/37 Model COSMO-7/8 12. Motor belt tension series Adjustment: 1. Remove the front cover. 2. Loosen two nuts (A) and adjust belt tension so that belt may be bent about 5 mm when it is pushed by pressure of 100g between upper shaft and motor.

  • Page 23: Retaining Bracket For Bobbin Case

    Original issue Service Manual January 2009 Page 23/37 Model COSMO-7/8 13. Retaining bracket for bobbin case series 1. Remove needle plate and bobbin case. 2. Check to see if corner of plate spring aligns with inside of wall (A) of shuttle race as illustrated below.
  • Page 24 Original issue Service Manual January 2009 Page 24/37 Model COSMO-7/8 13. Retaining bracket for bobbin case –continued -- series 6. Loosen screw (C) and adjust the position of reverse rotation stopper so that there may be a clearance of 1 to 1.5 mm between the projection and plate spring while turning the bobbin case back and forth.
  • Page 25 Original issue Service Manual January 2009 Page 25/37 Model COSMO-7/8 14. Origin point positioning of zigzag bight series Checking meshing position of gears This procedure is needed only when disassembling and re-assembling cams. Checking 1. Remove face cover and turn off power switch. 2.

  • Page 26: Stitch Length

    Original issue Service Manual January 2009 Page 26/37 Model COSMO-7/8 15. Stitch length series (A) Checking meshing position of gears This procedure is needed only when disassembling and re-assembling cams. Rotate motor gear clockwise to touch it with stopper pin and mesh these gears so that feed regulator gear may be positioned with full two gears below line from feed regulator to motor gear Stopper pin...
  • Page 27 Original issue Service Manual January 2009 Page 27/37 Model COSMO-7/8 15. Stitch length –continued-- series In case of large deviation, adjust as follows: Setting 1. Turn off power switch. 2. Loosen one of two screws on motor gear. 3. Turn on power switch and rotate hand wheel towards you, and this motor shaft will be held at one of exciting position continuously after motor for stitch width is held at exciting position.
  • Page 28 Original issue Service Manual January 2009 Page 28/37 Model COSMO-7/8 15. Stitch length --continued-- series (C) Stitch balance If forward and reverse stitch pitch is not balanced, adjust by changing position of motor. *Check meshing of motor gears and origin point positioning before adjustment. Checking Keyhole buttonhole is used to adjust stitch length, since many stitch patterns are built in this model:...
  • Page 29 Original issue Service Manual January 2009 Page 29/37 Model COSMO-7/8 15. Stitch length --continued-- series 2. Turn position adjusting bolt (B) on motor bracket in either direction using 3.0 mm hex driver. Change Inclination of feed regulator and stitch pitch will be varied: *Lower motor unit to change reverse stitch pitch.
  • Page 30 Original issue Service Manual January 2009 Page 30/37 Model COSMO-7/8 15. Stitch length --continued-- series b. Rotate bolt (B) counter clockwise when the top of buttonhole is shaped as (2) illustrated in the previous page Note: *Loosen screw (A) beforehand. *Don’t overshoot.
  • Page 31 Original issue Service Manual January 2009 Page 31/37 Model COSMO-7/8 16. Needle stop at highest position series Needle always stops at its highest position. This is controlled by sensor cam and sensor located on main shaft. Adjustment: 1. Raise needle to its highest position. 2.
  • Page 32 Original issue Service Manual January 2009 Page 32/37 Model COSMO-7/8 17. Electronic component area series AC Power Board Component number is for 120V spec. and for 230V spec. 87530 87553 Be sure to check number printed on board. 87530 & 87553 Transformer Secondary 5P Connector cord...
  • Page 33 Original issue Service Manual January 2009 Page 33/37 Model COSMO-7/8 17. Electronic component area -- continued -- series CPU board and SW board are unitized and located on control panel in this model. Be sure to check number printed on board. 84083 for model 7256, 84084 for model 7258 Start/atop switch, reverse stitch switch and ndl.
  • Page 34 Original issue Service Manual January 2009 Page 34/37 Model COSMO-7/8 17. Electronic component area -- continued -- series Harnesses are connected to red framed position of CPU board Reverse side of CPU /Switch board CN10 84082 LCD Unit p.no. not used...
  • Page 35 Original issue Service Manual January 2009 Page 35/37 Model COSMO-7/8 18. Wiring diagram series Model 7256...
  • Page 36 Original issue Service Manual January 2009 Page 36/37 Model COSMO-7/8 18. Wiring diagram – Continued-- series Model 7258...
  • Page 37 Original issue Service Manual January 2009 Page 37/37 Model COSMO-7/8 19. PART LIST FOR FEED CONTROL UNIT series Name Part no. 1 Motor bracket 87148 2 Metal bush 87178 3 Feed regulator 87254 4 Pinion gear 87253 5 Pulse motor 87600 6 Compression spring 87191...

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