Singer Advance 7422 User manual

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SERVICE MANUAL
MODEL 7422/7424/7426/7428
7442/7444/7446/7448
7462/7464/7466/7468

 Originalissue: April,2005 Part No. 77350
Revised: July,2005

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INDEX
Sec. 1 Disassembling of covers - - - - - - - - - - - - - - - - - - - - - - 1-6
Sec. 2 Test mode - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7-9
Sec. 3 Adjustment of feed dog height - - - - - - - - - - - - - - - - - - 10
Sec. 4 Needle bar height - - - - - - - - - - - - - - - - - - - - - - - - - - - 11
Sec. 5 Needle position at zigzag stitching - - - - - - - - - - - - - - - 12
Sec. 6 Clearance between needle and shuttle - - - - - - - - - - - - 13-14
Sec. 7 Needle timing to feed dog - - - - - - - - - - - - - - - - - - - - - 15
Sec. 8 Needle timing to shuttle hook - - - - - - - - - - - - - - - - - - -16
Sec. 9 Needle stopper at right position - - - - - - - - - - - - - - - - - 17
Sec. 10 Adjustment of thread tension - - - - - - - - - - - - - - - - - - - 18
Sec. 11 Zigzag bight & stitch balance - -- - - - - - - - - - - - - - - - - -19-25
Sec.12 Needle stops at heighest position - - - - - - - - - - - - - - - - -26
Sec.13 Electrical parts area
AC power board - - - - - - - - - - - - - - - - - - - - - - - - - - - - 27
CPU board - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -28-29
Switch board - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 30-34
Wiring harness - - - - - - - - - - - - - - - - - - - - - - - - - - - - -35-37

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
Sec.1Disassembling of covers
(1) Face cover side

Remove screw A.



Removescrew Ｂ.
(2) Back cover side

Remove two self-tapping screws.

A
B
D E

-4-

Remove two screws F & G.


Remove screw H.
Loosen screw J with washer.


Remove screw K on bottom side.
F G
H
J
K

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Remove screw L on bottom side.
Remove needle plate by loosening
two screws.

Push up front cove to open inserting
Small screw driver between front and
backcovers.

Open back and front covers.
L

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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.
40mm

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Lift up front cover as illustrated.
Lift up front cover as illustrated.
Lower presser foot lever to
removebackcovereasily.

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Disassembling of covers for model 7422
An additional bottom cover is provided on model 7422.
Remove screws S for front cover and then 5 screws on the bottom cover.
Disassembling of covers for model 7424・7426・7428
An additional bottom cover is provided on model 7424, 7426 and 7428.
Remove screws S for front cover and then 6 screws on the bottom cover.
Bottom cover
S
Bottom cover
S

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Sec.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.
5. LED is lit at the top left corner. 

7422, 7442,
7462
7424, 7444,
7464 and
others

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Note: Above operation is to be done in the following manner.
Steps 1 to 3

Steps 4 to 5
Release bobbin winder by the time when LED is lit at extreme right line.


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Test mode;
Mode 1:
In case of model 7422, 7442 and 7462, push switch at top right corner after machine is under test
mode as described above, and pattern LED will be lit at top left corner.
In case of other models, push pattern switch at top left corner after machine is under test mode and
the switch will be lit.
Needle shifts from left to center to right position repeatedly with foot control depressed.
Stitch length is set at “0”.
Mode 2:
In case of model 7422, 7442 and 7462, push switch at second row after machine is under test
mode and pattern LED will be lit at extreme left position.
In case of other models, push pattern switch at second position from left and the switch will be lit.
Needle moves at center position with foot control depressed. Stitch length is set at “0”.
Mode 3:
In case of model 7422, 7442 and 7462, push switch at third row after machine is under test mode
and pattern LED will be lit at extreme left position.
In case of other models, push pattern switch at third position from left and the switch will be lit.
Machine sews 11 stitches in forward with length at 2 mm and then same number of stitches in
reverse with length at 2 mm and stops automatically. Needle position is set at center position.

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Sec. 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 – 1.0 mm

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Sec. 4Needle bar height
Note: Make this checking before checking “Needle timing to shuttle”
Checking:
1. Remove needle plate and bobbin case.
Select straight stitch (center needle position).
Raise needle to its highest position by turning hand wheel.
2. Check to see if distance from needle point to the surface of needle plate is as
illustrated below.
Adjustment:
1. Remove face cover.
2. Loosen screw (A) of needle bar clamp using hex screw driver
and adjust the height of needle bar.
3. Check to see if needle threader operates correctly and there is not interference in vertical
movement of needle bar.
Tighten screw (A) securely after adjustment.
15.5 to 16 mm from
the surface of needle plate
Highest position
of Needle
Needle position
at center
A
B

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Sec. 5 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 hex screw (A) and adjust needle position by turning eccentric pin using 7mm
wrench.
b
a
a＝b
A

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Sec. 6 Clearance between needle and shuttle
Note: Make this checking before checking “Needle timing to shuttle”
Checking:
1. Remove needle plate, bobbin case and face cover.
2. Set test mode at 1.
3. 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 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

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2. If needle clearance to shuttle at right and left position is not same, adjust position
of fulcrum for needle swing support .
Loosen bolt located under bottom of support plate and adjust position of fulcrum.
3. After adjustment, tighten the bolt securely.
Do not loosen
this screw.

- 17 -
Sec. 7Needle timing to feed dog
Note: After adjustment, be sure to follow “Needle timing to shuttle”.
Checking:
1. Turning hand wheel, bring needle bar to it’s highest position.
2. Check to see if feed dog starts to move when needle starts to go down by
turning hand wheel towards you.
Adjustment:
1. Adjust the angle of timing gear to lower shaft with 2 screws on timing gear loosened and hex
driver inserted into one of the screws by turning main shaft with hand wheel,.
If feed-dog motion too early →Turn hand wheel towards you.
If feed-dog motion too late →Turn hand wheel away from you.
2. Tighten screw temporarily and check feed-dog motion.
Feed dog starts to move
almost at the same time
when needle starts to go
down.

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Sec. 8Needle timing to shuttle hook
Check “Needle timing to feed dog” and “Needle bar height” beforehand.

Checking:
1. Set mode at 1.
2. Remove needle plate. Check to see if needle is not bent.
3. Move needle to left position by turning hand wheel.
Raise needle from its lowest position slowly and check if distance is as illustrated below,
when point of shuttle hook aligns with right side of needle.
Adjustment:
1. Remove front cover. Loosen two screws on gear and adjust position of gear as illustrated
below.
With one screw tightened temporarily, check to see if the clearance is as illustrated above.
2. Adjust it by turning main shaft with hand wheel, with screws loosened and hex driver inserted
into one of the screws. Tighten screws securely after adjustment.
0.5〜0.8ｍｍ Point of shuttle hook

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Sec. 9 Needle stopper at right position
Note: Before checking, follow section “Needle position at zigzag stitching“
Checking:
1. Set test mode at 1. Remove face cover.
2. Bring needle to right position.
3. With needle bar touched with stopper at right side, check to see if needle collides with
presser foot and needle plate. It is acceptable if needle goes down along the edge of
needle plate.
Adjustment:
1. Loosen screw (A) and adjust the stopper in either direction. Tighten the screw securely after
adjustment.
Stopper
A

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Sec. 10 Adjustment of thread tension
Checking:
1.Set thread tension at the center of “AUTO” position.
2.Pull thread between tension discs and check thread tension value using 100 gr. tension gauge.
Measured value should be 40 to 50 g.
*When tension gauge is not available, do actual sewing and check balance of upper and lower
threads.
Adjustment:
1. Remove front cover and adjust by turning spring pressure adjustment screw.
*Turn it clockwise to increase tension.
*Turn it counter-clockwise to decrease tension.
