Singer XL-420 User manual

Service Manual
Original issue
May 2014
Page 1／64
Model
XL-420
| 1
XL-420
First issue: May, 2014

Service Manual
Original issue
May 2014
Page 2／64
Model
XL-420
| 2
SEC.1 Disassembling covers
SEC.2 Test mode with warning function deactivated
SEC.3 Needle clearance to shuttle
SEC.4 Alignment of needle plate to shuttle
SEC.5 Presser foot height and direction
SEC.6 Origin point positioning of zigzag bight
SEC.7 Needle bar height
SEC.8 Needle threader height
SEC.9 Adjustment of feed dog height
SEC.10 Tension of timing belt
SEC.11 Needle timing to feed dog
SEC.12 Needle timing to shuttle hook
SEC.13 Adjustment of timing of take-up lever to shuttle
SEC.14 Adjustment of meshing position of gears for take-up lever
SEC.15 Retaining bracket for bobbin case
SEC.16 Origin point positioning of feed “zero”
SEC.17 Stitch length
SEC.18 Ajustment of upper thread tension
SEC.19 Adjustment of CAM sensor
SEC.20 Check the Knee Lifter
SEC.21 Sewing machine test mode
SEC.22 Removing top cover and carriage cover of embroidery unit
SEC.23 Adjustment of stop position of embroidery carriage
along X & Y axis
SEC.24 Embroidery unit test mode
SEC.25 Trouble contents with LED on panel
SEC.26 Wiring diagram part1 & part2
SEC.27 Main circuit board and functions of each connector
Contents

Service Manual
Original issue
May 2014
Page 3／64
Model
XL-420
| 3
Ａ．Disassembling face cover
Ｂ．Disassembling bed cover
1. Pull out cap (not shown) in the center
and remove screw.
2. Loosen the screw behind.
3. Remove face cover
1. Pull out cap at bed cover using needle.
SEC.1-1 Disassemblin
g
covers
(
1
)

Service Manual
Original issue
May 2014
Page 4／64
Model
XL-420
| 4
Ｃ．Disassembling bobbin winder unit.
2. Loosen M4 screw.
3. Slide out bed cover.
1. Remove M3 screw at bobbin winding
latch.
2. Remove bobbin winding latch.
SEC.1-2 Disassembling covers (2)

Service Manual
Original issue
May 2014
Page 5／64
Model
XL-420
| 5
Ｄ．Removing switch cover
3. Remove M4 screw at bobbin winder
cover.
4. Remove two hooks at the side of the cover
from rear cover.
１．Removing M4 screws at the side of the cover.
SEC.1-3 Disassembling covers (3)

Service Manual
Original issue
May 2014
Page 6／64
Model
XL-420
| 6
Ｅ．Removing base cover
２．Remove switch cover.
１．Remove three M4 screws behind the sewing machine.
２．Lay the machine and remove two M3 tapping screws.
SEC.1-4 Disassembling covers (4)

Service Manual
Original issue
May 2014
Page 7／64
Model
XL-420
| 7
Ｆ．Remove front and rear covers.
３．Remove two M4 screws on the right.
４．Remove two M4 screws on the center.
1. Remove two M4 tapping screws near the handle at the top of rear
cover.
SEC.1-5 Disassembling covers (5)

Service Manual
Original issue
May 2014
Page 8／64
Model
XL-420
| 8
４． Lay the machine and open a rid behind the front cover by using a
small screw driver.
3. Remove M3 screw and washer at the front cover.
You can only loosen a screw but if you do so, be careful of a
position of washer when re-assembling.
2. Remove M4 screw at rear cover.
SEC.1-6 Disassembling covers (6)

Service Manual
Original issue
May 2014
Page 9／64
Model
XL-420
| 9
5. Insert small screw driver into clearance
between front and rear covers and then lift up the
front cover to remove two covers as shown at left.
* Once hooked portions A, B and C as shown
above are removed, other mating portions may be
removed easily.
Ａ Ｂ
Ｃ
6. Lay the machine on its back for easier removal
of covers. Remove front cover. Remove CPU
board and FFC-28 from front cover with care.
*FFC is flexible flat cable
SEC.1-7 Disassembling covers (7)
Ｂ
Ｃ

Service Manual
Original issue
May 2014
Page 10／64
Model
XL-420
| 10
7. Lower the presser foot lever and
then remove rear cover by lifting up
and passing it under the presser foot
taking care not to interfere with each
other.
This is a view of machine without front
cover.
This is a view of machine without
rear cover.
SEC.1-8 Disassemblin
g
covers
(
8
)

Service Manual
Original issue
May 2014
Page 11／64
Model
XL-420
| 11
This test mode is used to operate machine without threading, while sensors for
thread breakage, presser foot lever and bobbin thread are deactivated.
1. While pushing three switch buttons 1, 2 & 5 at control panel at the same, turn on
sewing machine.
2. Release three switch buttons after turning on the main power. Press start button and
sew straight stitch selected at default to check whether sensors are deactivated.
SEC.2 Test mode with warning function
deactivated

Service Manual
Original issue
May 2014
Page 12／64
Model
XL-420
| 12
Note: Select any of stitch number 33 to 36 and then set Zigzag width to the maximum of
7mm and then check needle clearance to shuttle at both left and right sides of needle
positions.
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 within 0.05 to 0.15 mm.
Adjustment:
1．Loosen screw for support shaft (A) and adjust needle position by moving support
shaft back and forth.
To decrease clearance, turn screw to clock wise
Shuttle
0.05 to 0.15mm 0.05 to 0.15mm
Extreme left Extreme right
0.05～0.15ｍｍ
SEC.3-1 Needle clearance to shuttle (1)
A
To clockwise

Service Manual
Original issue
May 2014
Page 13／64
Model
XL-420
| 13
2．If needle clearance to shuttle at right and left position is not same, adjust position of
fulcrum (B) for needle swing support.
Loosen socket screw (C) located under bottom of support plate and adjust position of
fulcrum.
3. After adjustment, tighten the bolt (C) securely.
If it touches at right side, adjust
position of fulcrum (B) for needle
swing support to the left.
B B B
SEC.3-2 Needle clearance to shuttle (2)
C
If needle touches with shuttle at left
side, adjust position of fulcrum (B) for
needle swing support to the right.

Service Manual
Original issue
May 2014
Page 14／64
Model
XL-420
| 14
Checking
1. After adjusting needle clearance to shuttle, attach needle plate. At this time, make sure
to check the needle is correctly positioned to the needle hole as shown below.
Adjustment:
1. Remove needle plate and loosen hexagonal screw (E) which fix needle plate stopper
plate (D) located at either side of feed dog. Then adjust stopper plate (D) so that to
needle plate may be positioned correctly to the needle.
2. Tighten the screw (E) at the stopper plate securely.
SEC.4
A
li
g
nment of needle plate to shuttle
E
D

Service Manual
Original issue
May 2014
Page 15／64
Model
XL-420
| 15
Checking-1
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.
Checking-2
1. Check to see if the position of presser foot is parallel to the ditch of feed dog on the
needle plate and carved line. And also check to see if the presser foot and ditch of
feed dog on the needle plate is equally balanced at left and right.
Checking-3
1. Check to see if the needle hole on the needle plate and the hole on the presser foot
are positioned same towards direction of fabric feed.
SEC.5-1 Presser foot hei
g
ht and direction
(
1
)
5.6mm

Service Manual
Original issue
May 2014
Page 16／64
Model
XL-420
| 16
SEC.5-2 Presser foot height and direction (2)
Adjustment-1
1．Remove the face cover, and set the feed-dog at down position.
2．Lower the presser foot lever.
3．Loosen screw (B) through hole (A) by using hexagon socket screw driver (2mm).
4．Tighten the screw (B) securely after checking the presser foot is parallel with the
holes for feed dog on the needle plate.
C
B
D
A

Service Manual
Original issue
May 2014
Page 17／64
Model
XL-420
| 17
SEC.5-3 Presser foot height and direction (3)
Adjustment-2
When needle ditch on the presser foot and needle hole at the needle plate do not match
towards fabric feed direction.
1. Insert screw driver as shown on picture below and loosen screw (D) at the upper
part of needle bar bracket (C)
2. After adjustment, tighten screw (D) securely and check to see whether presser foot
is operated smoothly with presser foot lever.
Shift presser foot backward to adjust.
Please note that parts of needle bar driving unit are removed in order to explain upper part (C)
and screw.
C D
B
Shift presser foot forward to adjust
Note: The presser foot
shown in this picture is
not for FQ-4

Service Manual
Original issue
May 2014
Page 18／64
Model
XL-420
| 18
SEC.5-4 Presser foot height and direction (4)
Adjustment-3
When the presser foot and ditch of feed dog on the needle plate is not equally
balanced to left and right direction
1. Loosen 3 screws at F, G and H at rear part of board (E).
2. Shake the board (E) to left and right around screw (F) and adjust presser foot to
balanced position as shown on below picture.
3. Tighten screw (B) properly after adjustment.
E
F
G
H
Shift the presser foot to the arrow as shown on above pictures to make
adjustment. Note: The presser foot shown in this picture is not for FQ-4

Service Manual
Original issue
May 2014
Page 19／64
Model
XL-420
| 19
Adjustment:
1. Turn off the main power and remove face cover.
2. Loosen two screws (1&2) fixing pinion gear by rotating pinion gear (A). Position of screw
(1) and screw (2) will be located as shown in fig. 1&2 below.
3. Rotate pinion gear (A) to shift needle position. After needle position is shifted to center,
temporally fix the screw (1).
4. Turn on the main power and pinion gear will move so that screw (1) may be located upward
and then loosen screw (1). After above steps, the motor shaft will be excited so the shaft
will not move and pinion gear can be rotatable. Rotate pinion gear (A) again until it hits with
stopper (B) then tighten screw (2) by inserting tool from lower as shown on picture below.
At this time, shift needle bar to right end so the pinion gear will hit with stopper.
2
A
Fig. 1 Fig. 2
1
B
2
SEC.6-1 Origin point positioning of zigzag bight

Service Manual
Original issue
May 2014
Page 20／64
Model
XL-420
| 20
Checking (2):
1. Turn on the machine and set at straight stitch.
2. Loosen screw (2) by using hexagon socket screw 1.5 at the Zigzag gear lever (D) and
rotate eccentric axis (3) in either direction to find a position of eccentric axis located on
the right and fix it.
3. Check whether needle is located at the center of needle hole in the needle plate
Adjustment (2):
1. Pinion of the motor is stationary due to excitation while machine is turned on.
Loosen a screw (C) at Zigzag lever (D) which is tightened temporarily and adjust Zigzag
lever to bring needle to the center of the needle hole.
2. Tighten the screw (C) securely after adjustment.
SEC.6-2 Origin point positioning of zigzag bight (2)
D
2
3