Janome Magnolia 7312 User manual

SERVICE MANUAL
MODEL 7312

TABLE OF CONTENTS
0. Dismantling the rear cover
1. Upper shaft end play
2. Cam stack gear mesh
3. Needle bar height
4. Shuttle timing
5. Needle position
6. Zeroing the needle
7. Feed dog height
8. Feed lifting cam
9. Stretch stitch selector cam
10. V belt adjusting
11. Bobbin winder
12. Take-up spring replacement and setting
13. Bobbin case tension
14. Stretch stitch sewing
15. BH balance
16. Electrical connections
PAGE
1
2
3
4
5
6
7
8
9
10
11
12-13
14
15
16
16
17

0. DISMANTLING THE REAR COVER
1. Unscrew the screws: a. b. c. d. e. f.
2. Open face cover and shuttle cover and pull out the spool
pins.
3. Remove the rear cover in direction of arrow.
a
b
e
f
c
d
spool pins
face cover
shuttle cover
1

1. UPPER SHAFT END PLAY
Check : 1. Hold clamp of stop motion by hand , check play
that push in and pull out on upper shaft.
According with above method, recheck upper
shaft play at any point during the revolution.
Adjustment : 1. Remove rear cover .
2. Loosen set screw (C) (Hexagen M5x5) in collor.
3. Plate screwdriver blade (E) between stop
clamp motion and casting body .
4. Hold collor (B) to left touch with slide front
spherical bearing of upper shaft (A) then
tighten set screw (C).
5. Take out screwdriver (E).
6. Recheck for end play.
(ALL MODELS)
2
ABCD
E
Front spherical bearing
Stop clamp motion

2. CAM STACK GEAR MESH
Check : 1. Remove rear cover.
2. Place machine in straight stitch.
3. Check at three different points in a full
revolution, zero or very slight play is
acceptable.
Adjustment : 1. Loosen set screw (E).
2. Hold gear (F) slightly forward, but can not
turn.
3. If machine marked bind, must be remove
backward.
4. Tighten set screw (E).
5. Recheck pendulum timing.
(ALL MODELS)
3
F
E

3. NEEDLE BAR HEIGHT
Check : 1. Take out bobbin case and shuttle race cap.
2. Select zigzag and max , width stitch.
3. Rotate hand wheel until needle is full down in
right position.
4. Then , slowly raise needle bar to (a) position ,
the distance shall be 1 mm.
Adjustment : 1. Open face cover.
2. Loosen needle bar clamp screw (A).
3. Slightly move needle bar (B) up or down until
location is 1 mm.
4. Tighten clamp screw (Torque 15kg-cm).
Attention : 1. After completing adjustment, make sure that
needle is parallel to shuttle.
(ALL MODELS)
AB
L
R
1 mm
shuttle hook
4
a

4. SHUTTLE TIMING
Check : 1. Take out bobbin case and shuttle race cap.
2. Select zigzag and max, width stitch.
3. Rotate hand wheel until needle is full down in
the left needle position.
4. The point of shuttle shall be 3.2 mm to the left
of needle.
Adjustment : 1. Remove rear cover.
2. Loosen 2 screw (A) on driver gear.
3. Slightly turn driver gear (B) clockwise to
decrease clearance and counter clockwise
to increase clearance.
4. Tighten both screw (A) and recheck.
(ALL MODELS)
C
A
B
3.2 mm
Shuttle hook
5
Lower shaft
a

5. NEEDLE POSITION
Check :
1. Set machine for zigzag max, width.
2. Turn machine by hand and
observe needle as it enters the
needle plate , left and right entry
should be equal distance from the
edge of the needle plate hole (A).
Adjustment :
1. Open face cover.
2. Loosen set screw (D) and (B).
3. Turn eccentric (C) as (A) shown.
(correct needle location).
4. Tighten set screw (B) and (D).
5. Check distance must be 0.4 mm
between needle bar and stopper
plate at the left or right position.
(ALL MODELS)
A
5 mm
D
B
C
0.4 mm
6

6. ZEROING THE NEEDLE
Check : 1. Select straight stitch position.
2. Sewing a line straight stitch.
3. Shall be no or minimul movement below
0.3 mm.
Adjustment : 1. Remove rear cover.
2. Select straight stitch position.
3. Loosen screw (or nut ) (A).
4. Remove connecting plate (B) so that no or
minimul movement of needle bar.
5. Tighten screw (or nut ) (A).
(ALL MODELS)
A
B
BA
C
Model
Model
7

7. FEED DOG HEIGHT
Check : 1. Bring feed dog to it's highest point.
2. The top or the feed dog should be 0.8-1.0 mm
above the surface of the needle plate.
Adjustment : 1. Remove rear cover.
2. Bring feed dog to it's highest point.
3. Loosen nut (A).
4. Turn set screw (B) as required.
5. Tighten nut (A).
(ALL MODELS)
0.8~1.0 mm
Feed dog
Needle plate
8
A
B

8. FEED LIFTING CAM
Check : 1. Turn the hand wheel to make needle
point position about above needle plate.
2. At this time, teeth of feed dog are required
to keep same height with that of needle
plate surface.
Adjustment : 1. Remove rear cover.
2. Loosen feed lifting cam set screw
(Hexagon M5x5) (A).
3. Turn feed lifting cam (B) up to same height
of feed dog teeth and needle plate surface,
(As F. 2 shown).
4. Tighten set screw (A).
(ALL MODELS)
AB
FIG. 2
9

9. STRETCH STITCH SELECTOR CAM
Check : 1. Set pattern selector dial at (A) and (D).
2. Sewing (A) and (D) pattern.
3. Sewn-out look (A) and (D), stitch length must
be same.
Adjustment : 1. Remove rear cover.
2. Set pattern select dial at (A) position.
3. Loosen two set screw (Hexagon M4x4) (E)
and (F).
4. Turn SS selector cam (G) up to distance
above 1 mm of pin (H) and SS selector
cam end.
5. Then tighten (E).(F) two set screw.
MODEL : JANOME 7312
E
F
H
G
E
F
GH
A
B
C
D
1.0mm
10
D
C
B
A

10. V BELT ADJUSTING
Check : 1. Remove rear cover and front cover.
2. Belt about parallel of two side during
pressure 300g use spring gauge measured.
Adjustment : 1. Remove rear cover and front cover .
2. Loosen two screw of motor (B).
3. Movement motor up and down, adjusting belt
tension until as required.
4. Tighten two nuts.
(ALL MODELS)
BC
A 300g
Motor belt
11

12
11. BOBBIN WINDER
Clamp stop motion washer
Check: 1. loosen clamp stop motion large screw (A) and run
machine.
2. Hand wheel (C) should rotate freely without needle
bar moving up or down.
3. Tighten clamp stop motion large screw (A) and sew
over heavy seam (6 ply denim or equivalent).
4. Clamp stop motion large screw (A) should not
loosen.
Adjustment: 1. Loosen stop screw (B) .
2. Unscrew and remove clamp stop motion large
screw (A) carefully so as not to disturb clamp stop
motion washer (E).
3. Remove clamp stop motion washer (E) and rotate
1/2 turn(180 ).
Replace in machine being sure the ears (D) are
bent away from the machine.
4. Replace clamp stop motion large screw (A)
and tighten screw (B).
5. Recheck for proper operation.
Bobbin winder
Check: 1. Wind a bobbin and check if thread is wound evenly
(F) ,or forms a cone at eigther end (G) or (H).
2. The bobbin winder should stop turning when the
thread is wound to within 0.8mm-1.5mm from the
outer rim of the bobbin.
Adjustment: 1. Loosen screw(J).
2. If bobbin is wound unevenly as in (G), move thread
guide (I) up.
3. If bobbin is wound unevenly as in (H) , move thread
guide (I) down.
4. Tighten screw (J) and recheck.
5. If bobbin winder stopper (K) engages too soon or
fails to operate, loosen screw (L) and move stopper
clockwise to give less thread on the bobbin or
counter clockwise to give more thread on the bobbin.
Throw of stopper (K) should be toward the right of
the machine.
6.Tighten screw (L) and recheck.
(ALL MODELS)

K
I
A
D
C
L
J
0.8~1.5mm
FGH
11.
B
E
13

12.TAKE-UP SPRING REPLACEMENT AND SETTING
Check : 1. Open face cover.
2. Check to this "take-up spring", in normal it
should touch to (A) , and take-up spring
should be 1~1.5 mm (B).
3. When this spring in operation (Lift in arrow
direction) tension be 6g~12g.
Adjustment : 1. Loosen set screw (C).
2. Turn the spring (D).
In clockwise to increase tension.
In counter clockwise to decrease tension.
Adjust until this spring tension reaches
6g~12g.
3. Tighten set screw (C).
6g~12g D
C
B 1~1.5mm
A
C
14
(ALL MODELS)

13. BOBBIN CASE TENSION
Adjustment : 1. Remove bobbin case.
2. Insert a fully wound bobbin in case and
thread normally.
3. Remove shuttle race cap.
4. Tie race cap to thread from bobbin case.
5. Hold bobbin case upside down without
touching tension spring.
6. Loosen tension spring adjustment screw (L)
until weight of race cap stars pulling thread
from bobbin case.
7. Gradually tighten screw (L) until bobbin stops
turning.
L
(ALL MODELS)
15

14. STRETCH STITCH SEWING
Check : 1. Set the pattern selector at ( ).
2. Sewn-out patterns look not like (a) patterns
are too far and (c) patterns are overlap.
Adjustment : 1. Remove rear cover .
2. Loosen nut (F).
3. If sewn-out patterns look like (a), the nut (G)
must be clockwise turn until nice pattern can
be sewn-out like (b).
4. If sewn-out patterns look like (C), the nut (G)
must be counter clockwise turn until nice
pattern can be sewn-out like (b).
5. Tighten 2 nuts (F, G.).
15. BH BALANCE
Check : 1. Sew a buttonhole.
2. Check that both legs of the buttonhole have
equal stitch density.
Adjustment : 1. Remove rear cover .
2. Placement machine in step 3 of buttonhole.
3. Loosen 6mm nut (B).
4. Turn adjustment screw (A) clockwise to
increase stitch length on right leg.
Counter clockwise to shorter stitch length.
5. Tighten lock nut (B).
6. Check buttonhole balance.
TURN COUNTER CLOCKWISE
TURN CLOCKWISE
B
A
F
G
16
abc
MODEL: JANOME 7312
MODEL: JANOME 7312

16. ELECTRICAL CONNECTIONS
17
Switch
Light
Motor
120V
(FDM TYPE)
230V
(FDM TYPE)
Cap
Motor