Singer 8763 CURVY User manual

Service Manual
8763
8770
104 72 90-26
4 March 2008

Page 2/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
INDEX
1. Disassembling of covers
2. Test mode
3. Adjustment of feed dog height
4. Needle bar height
5. Needle threader height
6. Presser foot height and direction
7. Needle position at zigzag stitching
8. Clearance between needle and shuttle
9. Needle timing to feed dog
10. Needle timing to shuttle hook
11. Adjustment of take-up lever timing to needle
12. Adjustment of meshing position of gears for thread take-up lever
13. Adjustment of thread tension
14. Tension of timing belt
15. Motor belt tension
16. Retaining bracket for bobbin case
17. Origin point positioning of zigzag bight
18. Stitch length (Full-step version)
19. Needle stop at highest position
20. Electronic component area
*AC Power board
*CPU board-1
*Switch board-1
21. Wiring diagram
22. Part list for feed control unit

Page 3/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
1. Disassembling of covers
(1) Face cover side
Remove screw A.
Remove screw Ｂ.
(2) Bottom side
Loosen three screws.
A
B

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Original issue
Dec.2007
Service Manual
COSMO-II series
Model
1. Disassembling of covers –continued--
Remove a screw on front cover.
外す。
Remove a screw inside of access
hole of front cover.
Don’t remove screws above and
Below the access hole
Remove cap for fine adjustment on
assembly.
微調整用（生産用）キャップを

Page 5/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
1. Disassembling of covers –continued--
(3) Back cover side
Remove two self-tapping screws.
Remove two screws
Remove self-tapping screw.

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Service Manual
COSMO-II series
Model
1. Disassembling of covers –continued--
Pre-tension unit is removed.
(4) Front cover side
Loosen screw A.
A
Remove screws (A & B) on pre-tension unit.
B
A

Page 7/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
1. Disassembling of covers –continued--
Open back and front covers.
Push up front cover to open by inserting
small screw driver between front and
back covers.
Open mating portion of front and back
covers by pushing back cover with small
screw driver.
Open
front cover with
smallscrewdriver.
Lift up front cover.

Page 8/47
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Dec.2007
Service Manual
COSMO-II series
Model
2. Test mode
1. Push bobbin winder to the right
2. Push and hold reverse switch
in place.
3. Turn on power switch.
4. Release bobbin winder while
pushing reverse switch, just after
power switch is turned on.

Page 9/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
2. Test mode -- continued --
(A) Model 8763
Mode 1 : zero feed, three needle positions (L/C/R)
Mode 2 : zero feed, center needle position
Mode 3 : 2 mm feed, center position, sews 11 stitches forward and backward.
5. Select key 1 by pushing switch at
right
Release bobbin winder by the time when LED is lit at extreme right line.
Key 1 is mode 1.
Take the same procedures for further
modes up to 3.

Page 10/47
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Dec.2007
Service Manual
COSMO-II series
Model
2. Test mode -- continued --
(B) Model 8763
Selecting test mode
(a) Push one of 5 buttons below LCD display to select test mode 1 to 5. Modes 4 and 5 are
for factory use only.
(b) Push one of direct selection buttons to select test mode 1 to 6. Modes 4, 5 and 6 are
for factory use only.
Mode 1 : zero feed, three needle positions (L/C/R)
Mode 2 : zero feed, center needle position
Mode 3 : 2 mm feed, center position, sews 11 stitches forward and backward.
Release bobbin winder while keeping pushing reverse stitch button.

Page 11/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
3. Adjustment of feed dog height
Checking:
1. Move feed dog to its highest position by turning hand wheel.
Check to see if feed dog height is as illustrated below.
Adjustment:
1. Remove needle plate. Loosen nut with wrench.
2. Adjust height by turning screw as illustrated. Tighten nut securely after adjustment.
0.9 – 1.1 mm

Page 12/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
4. Needle bar height
Note: Make this checking before checking “Needle timing to shuttle” and
”Feed-dog timing (vertical motion)”. Use needle Singer 90/14.
Checking:
1. Select straight stitch at center needle position.
2. Remove presser foot and needle plate, and then remove bobbin case.
3. Replace needle with special needle gauge (L=28.5 mm).
4. Lower the needle gauge to its lowest position by turning hand wheel by hand.
Check to see if the bottom of the needle gauge aligns with shuttle race pushing
the needle lightly as shown by arrow mark.
Adjustment:
1. Remove face cover.
2. Loosen screw (A) of needle bar clamp using hex screw driver
and adjust the height of needle bar.
Highest position of
Needle
Needle position
at center
A
Needle gauge L =29 mm
Shuttle race

Page 13/47
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Dec.2007
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COSMO-II series
Model
4. Needle bar height –continued--
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 14/47
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Dec.2007
Service Manual
COSMO-II series
Model
5. Needle threader height
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.
Adjustment
1. Remove face cover.
2. Turning hand wheel by hand, raise needle bar to its highest position.
3. Loosen screw (B) of threader stopper.
4. Insert hook into the upper side of needle hole moving the needle bar (C).
5. While holding the above situation, tighten the screw (B) attaching the threader
stopper onto stopper pin (D).
6. The direction of threader stopper should be facing toward you so that it may
not hit the needle support bracket.
＊Insert the hook into the upper side of needle hole at all times as the smaller
needle size, the shorter needle hole.
B
D
B
C
Threader stopper

Page 15/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
5. Needle threader height --continued--
7. If the direction of insert hook is deviated from correct position, adjust the hook
position with the small screw driver in the accessory.
8. If hook protrudes from needle hole too much or little, it may affect threading
condition. Loosen nut (F) under threader support shaft and turn hook portion
(G) in either way for adjustment. Tighten the nut (F) securely after adjustment.
Needle hole Hook
Insert the hook into the
upper side of needle hole.
90/14 80/11 70/9
Hook
F
G F G

Page 16/47
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Dec.2007
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COSMO-II series
Model
5. Needle threader height -- continued --
9. If twin thread guide (H) is located much higher or lower than hook portion, needle
is not threaded as shown in Fig. 1.
Adjust position of outer pipe (J) so that there may be a clearance 0.4 to 0.6 mm
between screw (K) and bottom of long hole.
Hook protrudes
too much.
Hook protrudes
correctly.
Hook protrudes
too little.
Needle
Hook
Hook holder
H
Fig.1
0.4 to 0.6mm
K
J

Page 17/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
5. Needle threader height -- continued --
If it doesn’t work correctly yet, adjust position of root (L) of twin thread guide (H)
vertically with threading lever lowered.
10. Check that the needle threader works correctly.
Guide (M)
Hook
Hook
Guide (M)
Position of twin thread guide and hook is
shown below with threading lever lowered.
thread guide is
locates too low.
It is located correctly.
It is located too
high.
L
H

Page 18/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
6. Presser foot height and direction
Checking
1. Lower the feed dog below the needle plate.
2. Raise the presser foot lever.
3. Check and see if clearance between needle plate and presser foot is about 5.6 mm.
Adjustment
1. Remove the face cover, and Raise the presser foot lever.
2. Loosen the screw (A) and adjust the presser foot height moving the presser bar.
3. Tighten the screw securely after checking the presser foot is parallel with the holes for
feed dog on the needle plate.
5.6 mm
A
A

Page 19/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
7. Needle position at zigzag stitching
Checking:
1. Set test mode at 1.
2. Turn hand wheel by hand and see if needle leaves the same clearance at both right
and left end of needle plate hole.
Adjustment:
1. Loosen screw (A) and adjust needle position.
b
a
a＝b
A

Page 20/47
Original issue
Dec.2007
Service Manual
COSMO-II series
Model
8. Clearance between needle and shuttle
Note: Set machine at test mode and select mode 1 for needle at L/C/R
positions. Make this checking before checking “Needle timing to shuttle”.
Checking:
1. Remove needle plate, bobbin case and face cover.
2. Shift shuttle hook at the rear of needle by turning hand wheel.
Check to see if needle clearance to shuttle is within 0.05 to 0.15 mm.
Adjustment:
1. Turn screw (A) to either direction as illustrated and adjust needle position by moving
support shaft back and forth.
To decrease clearance, turn screw to counter-clockwise.
Shuttle
0.05～0.15ｍｍ 0.05～0.15ｍｍ
At left position At right position
0.05～0.15ｍｍ
At left position At right position
A