Janome MC400E User manual

SERVICE MANUAL
MODEL: MC400E
First Edition: 29 February 2016

INDEX
Replacing External Parts
Face cover.................................................................................................................................................................1
Thread cutter cover ..................................................................................................................................................1
Base plate..................................................................................................................................................................2
Bed cover ..................................................................................................................................................................3
Front cover ................................................................................................................................................................4
Rear cover.................................................................................................................................................................5
Carriage cover...........................................................................................................................................................6
Belt cover...................................................................................................................................................................6
Mechanical Adjustment
Needle drop position..................................................................................................................................................7
Hook timing................................................................................................................................................................8
Needle bar height ......................................................................................................................................................9
Clearance between the needle and hook................................................................................................................10
Backlash between the rotary hook gear and lower shaft gear.................................................................................11
Upper shaft shield position ................................................................................................................................ 12-13
Needle thread tension .............................................................................................................................................14
Tension release mechanism....................................................................................................................................15
Height of the embroidery foot ..................................................................................................................................17
Presser foot lifter detecting switch...........................................................................................................................20
Automatic thread cutter ...........................................................................................................................................21
Remaining bobbin thread sensor.............................................................................................................................22
Hoop position...........................................................................................................................................................23
X-sensor position.....................................................................................................................................................25
Y-sensor position .....................................................................................................................................................26
Y-carriage supporter ................................................................................................................................................27
DC Motor belt deection..........................................................................................................................................29
Replacement
Needle threader.......................................................................................................................................................16
Printed circuit board A..............................................................................................................................................18
Printed circuit board F .............................................................................................................................................19
Carriage unit............................................................................................................................................................24
Switching power supply...........................................................................................................................................28
Driving motor ...........................................................................................................................................................29
Replacing the Gear of the X-carriage......................................................................................................................30
Oiling
Needle bar, presser bar and thread take-up lever...................................................................................................31
Oil wick ....................................................................................................................................................................32
Lower shaft supporter (front and rear).....................................................................................................................32
Y-carriage ................................................................................................................................................................33
X-carriage................................................................................................................................................................33
PARTS LIST...................................................................................................................................................... 34-51

1
MC450e
Replacing External Parts (1) Face Cover and Thread Cutter Cover
Replacing the face cover
To remove:
1. Remove the setscrew and remove the face cover.
To attach:
2. Follow the above procedure in reverse.
Face cover
Setscrew
Replacing the thread cutter cover
To remove:
1. Remove the cap and setscrew (A).
Stand the machine so the handwheel side comes to
the underside of the machine.
Insert the screwdriver from the bottom hole of the
thread cutter cover.
Loosen the setscrew (B).
Remove the thread cutter cover.
To attach:
2. Follow the above procedure in reverse.
Cap Setscrew (A)
Thread cutter cover
Setscrew (B)

2
MC450e
Replacing External Parts (2) Base Plate
Replacing the base plate
To remove:
1. Stand the machine so that the handwheel side
comes to the underside of the machine.
2. Remove the 6 setscrews (A) and remove the bottom
plate.
Setscrews (A Setscrews (A)
Bottom plate
To attach:
3. Follow the above procedure in reverse.

3
MC450e
Setscrew (A) Setscrew (A)
Needle plate
Bed cover
Rear cover Hook
Hook
Hook
Rear cover
Bed cover
Replacing External Parts (3) Bed Cover
Replacing the bed cover
To remove:
1. Turn the power switch on to move the carriage to the
stored position, then turn the power switch off.
2. Remove the setscrews (A) and the needle plate.
Remove the base plate (refer to page 2).
3. Remove the bed cover while pushing the rear cover
to unlock the hooks.
To attach:
4. Follow the above procedure in reverse.

4
MC450e
Replacing External Parts (4) Front Cover
Replacing the front cover
To remove:
1. Remove the face cover and bed cover (refer to pages
1 and 3.).
Turn the power switch on.
Press the built-in design key q and the rst page of
the design list of Petite Designs will open.
Press the embroidery pattern #1 wto move the
carriage to the starting position, then turn the power
switch off.
Setscrew (A)
q
w
2. Loosen the setscrew (A).
Setscrews (B)
3. Remove the 2 setscrews (B) near the spool pin.
4. Remove the cap and setscrew (C).
Remove the belt cover.
Setscrews (C)
5. Remove all the connectors from the pointed circuit
board A and unlock the hooks, then remove the front
cover.
To attach:
6. Follow the above procedure in reverse.
NOTE:
Refer to page 18 to locate the connectors.
Belt cover

5
MC450e
Replacing External Parts (5) Rear Cover
Replacing the rear cover
To remove:
1. Remove the face cover, base plate and bed cover.
2. Remove the setscrew (A).
Setscrew (A)Rear cover
Setscrews (B)
Setscrews (C)
Setscrews (D)
Setscrew (E)
Setscrew (F)
3. Remove the 2 setscrews (B) and 3 setscrews (C).
Y-carriage
supporter
4. Remove the 2 setscrews (D).
5. Loosen the setscrew (E).
6. Loosen the setscrew (F), and shift the Y-carriage
supporter up.
7. Unlock the hooks, raise the carrying handle and
remove the rear cover by opening the left end of the
covers.
To attach:
8. Follow the above procedure in reverse.
NOTE:
Adjust the Y-carriage supporter (refer to page 27).

6
MC450e
Replacing External Parts (5) Carriage Cover and Belt Cover
Replacing the Carriage Cover
To remove:
1. Remove the setscrew (A).
Setscrew (A)
Setscrew (B)
2. Remove the setscrew (B).
Remove the carriage cover.
To remove:
3. Follow the above procedure in reverse.
Setscrew (A)
Replacing the Belt Cover
To remove:
1. Remove the cap and setscrew (A).
2. Remove the belt cover.
To remove:
3. Follow the above procedure in reverse.
Belt cover

7
MC450e
Adjusting the Needle Drop Position
1. Lower the needle to the lowest position by turning the
handwheel.
2. Remove the face cover (refer to page 1).
3. Loosen the 2 setscrews (A).
4. Move the needle bar supporter back or forth to adjust
the position of the needle.
5. Loosen the setscrew (B).
6. Move the needle drop adjusting plate laterally to
adjust the position of the needle.
7. Tighten the setscrews.
8. Attach the face cover.
NOTE:
Check the hook timing (refer to page 8) and clearance
between the needle and hook (refer to page 10). Adjust
them if necessary.
The needle should be positioned at the center of the needle plate hole.
Setscrew (B)
Needle bar
supporter
Setscrews (A)

8
MC450e
Adjusting the Hook Timing
1. Remove the needle plate and bottom plate (refer to
page 2).
2. Remove the presser foot and the bobbin holder.
Attach a #11 blue tip needle.
3. Lower the needle bar to its lowest position by turning
the hand wheel toward you.
4. Raise the needle bar 3.25 to 3.55 mm up from the
lowest position.
5. Loosen the setscrews on the lower shaft gear.
Turn the lower shaft gear until the tip of the rotary
hook meets the right side of the needle, while holding
the hand wheel so the needle bar does not move.
6. Tighten the setscrews.
7. Attach the bobbin holder, needle plate and presser
foot. Replace the needle with the #11 needle.
8. Attach the bottom plate and needle plate.
The hook timing is an amount of ascending travel of the needle bar from its lowest position to
where the tip of the rotary hook meets the right side of the needle that should be 3.25 to 3.55 mm.
Needle plate
Bobbin holder
Tip of the rotary hook
#11 needle
3.25 to 3.55 mm
Lowest position
Setscrew
SetscrewLower shaft gear

9
MC450e
Adjusting the Needle Bar Height
1. Remove the face cover (refer to page 1).
2. Remove the presser foot, needle plate and bobbin
holder. Attach a #11 needle.
3. Turn the hand wheel to raise the needle bar from the
lowest position until the tip of the rotary hook meets
the right side of the needle.
4. Loosen the setscrew on the needle bar supporter.
Move the needle bar up or down to set the distance
between the top of the needle eye and the upper
surface of the rotary hook at 1.6 to 2.0 mm.
5. Tighten the setscrews. Be sure that the groove of the
needle is facing right in the front.
6. Attach the bobbin holder, needle plate and presser
foot. Replace the needle with the #11 needle.
7. Attach the face cover.
The distance between the top of the needle eye and the upper surface of the hook race should be 1.6
to 2.0 mm when the tip of the rotary hook meets the right side of the needle in the ascending travel
form the lowest position.
1.6 to 2.0 mm
Upper surface of the hook race
Top of the needle eye
Rotary hook
Setscrew
Needle bar
Needle plate
Bobbin holder
Tip of the rotary hook
#11 needle
Groove

10
MC450e
Adjusting the Clearance between Needle and Hook
1. Remove the base plate (refer to page 2).
2. Remove the presser foot, needle plate and bobbin
holder. Replace the needle (#11) with the test pin.
3. Loosen the setscrews (A), (B) and (C) and tighten the
setscrew (C) slightly.
4. Turn the hand wheel to bring the tip of the rotary hook
behind the test pin.
Adjust the clearance between the test pin and the tip
of the rotary hook to -0.10 to +0.05 mm by moving the
rotary hook set plate up or down.
5. Tighten the setscrews (A), (B) and (C) rmly.
6. Check the backlash between the rotary hook gear and
lower shaft gear and adjust the backlash if necessary.
7. Attach the bobbin holder, needle plate and presser
foot. Replace the test pin with the #11 needle.
8. Attach the bed cover.
The clearance between the needle and the rotary hook should be -0.10 to +0.05 mm.
Test pin
Tip of rotary hook
-0.10 to +0.05 mm
Setscrew (A) Setscrew (C)
Setscrew (B)

11
MC450e
Adjusting the Backlash between the Rotary Hook Gear and Lower Shaft Gear
1. Remove the bed cover (refer to page 3).
2. Remove the needle, presser foot, needle plate and
bobbin holder.
3. Loosen the setscrew.
Check the rotary play of the hook.
4. Turn the lower shaft bushing (eccentric) in the
direction “A” if the gears do not turn smoothly.
Turn the lower shaft bushing in the direction “B” if the
rotary play is larger than 0.8 mm.
5. Tighten the setscrew.
6. Attach the bobbin holder, needle plate, presser foot
and needle.
7. Attach the bed cover.
The rotary play of the hook should be 0. 8 mm or less.
A
B
Setscrew
Lower shaft bushing
Rotary play should be
0.8 mm or less.

12
MC450e
Printed circuit board L2
Adjusting the Upper Shaft Shield Position
1. Remove the face cover, bed cover and front cover (refer
to pages 1,3 and 4). Attach the needle plate.
2. Remove the setscrews (A) and printed circuit board F
from the front cover.
The needle height should be at 8.2-9.2 mm above the needle plate surface when the “Bight” phase
changes from “L” to “H”.
Setscrews (B)
Setscrews (A)
Front cover
Printed circuit board F
3. After disconnecting all of the connector, remove the
setscrews (B) to remove the printed circuit board A
from the front cover.
4. Reconnect the connectors to the printed circuit board
A except printed circuit board L2 and L3 connectors.
* The carriage will not return to the home position after
turning the power switch on if the X-motor connector
is disconnected.
(To be continued to the next page.)
X motor connector
Printed circuit
board L3
Phase key
To adjust:
To check:
1. Attach the needle #11.
Turn the power switch on while pressing the Start/
stop button to enter the factory setting mode.
Press “Phase” key.
2. Turn the handwheel toward you slowly until the
needle from its lowest position until “Bight” changes
from “L” to “H”.
3. The needle height should be 8.2 to 9.2 mm above
from the surface of the needle plate. If not, adjust the
upper shield position.
8.2–9.2 mm
#11 Blue needle
Start/stop button

13
MC450e
6. Turn the handwheel toward you and raise the needle
8.7 mm above the surface of the needle.
8.2–9.2 mm
#11 Blue needle
5. Turn the power switch on while pressing the Start/
stop button to enter the factory setting mode.
Press “Phase” key.
Phase key
Setscrew (C)
Even
Sensor
Upper shaft shield plate
Fig. 1
Bight sensor
Upper shaft shield plate Bight shield plate
Start/stop button
Printed circuit board F
7. Loosen the setscrew (C) of the upper shaft shield
plate. Turn the upper shaft shield until “Bight”
changes L to H.
Tighten the setscrew (C).
* The position of the upper shaft shield plate should be
in the center of the upper shaft sensor (see Fig. 1.)

14
MC450e
Adjusting the Needle Thread Tension
The standard upper thread tension should be 59 to 67 gram-force when pulling the thread (white
polyester thread size 50) at the speed of 110 mm/sec with the tension at “3.4” (Be sure the presser
foot is lowered).
To check:
1. Lower the presser foot.
2. Turn the power switch ON while pressing the start/
stop button.
Press “Foot Sensor/Tension” key.
3. Press “Free” key.
The tension disc will be opened with the presser foot
lowered.
4. Thread white polyester thread (size 50) to the
machine.
5. Press “3.4” key.
The tension discs will be closed and the thread
tension will be set at “3.4”.
6. The upper thread tension should be 59 to 67 grams
when pulling the thread at the speed of 110 mm/sec.
If not, adjust the needle thread tension.
Foot Sensor/Tension key
Start/stop button
Pulling direction
(Pulling speed 110 mm/sec.)
Free key
3.4 key
To adjust:
1. Lower the presser foot.
2. Turn the power switch ON while pressing the start/
stop button.
Press “Foot Sensor/Tension” key.
3. Press “Free” key.
The tension disc will be opened with the presser foot
lowered.
4. Thread white polyester thread (size 50) to the
machine.
5. Press “3.4” key.
6. Remove the face cover (refer to page 1).
Adjust the tension by turning the thread tension
adjusting screw.
To loosen the tension, turn it clockwise (in the
direction of “–”).
To tighten the tension, turn it counterclockwise (in the
direction of “+”).
Thread tension
adjusting screw
–
+

15
MC450e
Thread tension release
adjusting plate
Adjusting the Tension Release Mechanism
When the presser foot is lowered, the thread tension will be closed and pull the thread.
When the thread tension will be released, the tension disc will be opened and release the
thread correctly.
1. Remove the front cover (refer to page 4).
2. Turn the power switch ON while pressing the start/stop
button.
Press “Foot Sensor/Tension” key.
3. Press “Free” key.
The tension disc will be opened with the presser foot
lowered.
Lower the presser foot.
4. Turn the thread tension gear until the convex part of
tension gear is not set at the tension release claw.
5. Loosen the setscrews (A) and (B).
6. Adjust the clearance between the tension release
adjusting plate and the tension disc supporter to 0.2
mm - 0.8 mm as shown in Fig. B.
  Tightenthesetscrew(A)rst,andadjustthethread
tensionreleaseadjustingplateposition,thentighten
the setscrew (B).
Be sure that the tension release lever touches to the
presser foot lifter as shown in Fig. C when tightening
the setscrew (B).
7. Turn the thread tension gear until the convex part
of tension gear is engaged with the tension release
claw. Be sure that the tension release adjusting plate
touches to the tension disc supporter and the tension
discs are opened slightly (see Fig. D and E).
Convex is NOT set at release claw
Thread tension gear
Convex part of
tension gear
Setscrew (A)
Thread tension
release adjusting
plate
Tension
release
claw
Setscrew (B)
Foot Sensor/Tension key Free key
0.2−0.8mm
Tension release lever
Presser foot lifter
The tension release
lever touches to the
presser foot lifter.
Fig. B
Fig. A
Fig. C
Convex is set at release claw
Convex part of
tension gear
Tension
release
claw
Tension disc supporter
Tension disc supporter
Thread tension release
adjusting plate
Tension disc
(closed)
Tension
disc
(opened)
Fig. D
Fig. E

16
MC450e
Replacing and Adjusting the Needle Threader
If the hook of the needle threader is damaged, replace the threader plate as follows.
Threader plate supporter (A)
Pin (B)
Hook
Groove
To remove:
1 Push down the needle threader knob and pull the
needle threader plate (A) down to remove it (see Fig. A).
To attach:
1. To install the needle threader plate, line the groove up
with the pin (B) and push it up to snap it.
To adjust:
1. If the hook on the threader plate touches the left or
right side of the needle eye, loosen setscrew (C) and
adjust the hook position (Fig. B).
View A
View A
Hook
Setscrew (C)
Threader plate
Fig. A
Fig. B
Needle bar Setscrew (D)
Threader position set plate
Fig. C
Needle threader lever
2. If the hook on the threader plate touches the top or
bottom side of the needle eye, loosen setscrew (D)
and adjust the hook position (Fig. C).

17
MC450e
Adjusting the Height of the Embroidery Foot
Space between the needle plate and bottom of the embroidery foot should be 0.9 to 1.5 mm
when the presser bar is at its lowest position.
1. Remove the face cover (refer to page 1).
2. Lower the presser foot.
Turn the handwheel toward you to lower the
embroidery foot at its lowest position.
3. Loosen the setscrew (A) on the presser bar
supporter.
4. Place the 1.2 mm spacer (block) between the presser
foot and the needle plate.
5. Fix the presser bar link by tightening the setscrew
with holding the presser foot actuator arm against the
cam.
6. Check “Presser Foot Lifter Detecting Switch” (refer to
page 20).
Setscrew (A)
Presser
foot bar
supporter
1.2 mm
Surface of
needle plate
Embroidery foot
Presser foot actuator arm Cam

18
MC450e
Replacing the Printed Circuit Board A
To remove:
1. Remove the face cover, bed cover and front cover (refer
to pages 1, 3 and 4).
2. Disconnect all the connectors from the printed circuit
board A.
3. Remove the 3 setscrews (A) and remove the printed
circuit board A with the case.
4. Remove the 4 setscrews (B) and remove the printed
circuit board A from the case.
To attach:
1. Follow the above procedure in reverse.
NOTE:
Refer to the following diagram when connecting the
connectors.
Setscrews (B)
Setscrews (A)
Setscrew (B)
Printed circuit
board A
Case
Disconnecting LCD Module Flexible PCB
Flexible PCB
Lift up the clamp to unlock.
Close the clamp to lock.
Touch panel (Black) Program (slave)(Black)
Printed circuit
board L1(Black)
Printed circuit board L2 (White)
Printed circuit
board L3(Red)
Printed circuit board F(Black)
Presser foot lifter sensor(Black)
Thread detection sensor (White)
Switching power supply (White)
Thread cutter motor (White)
Switching power supply (White)
Y-motor
Bobbin thread
detecting sensor (Green)
Bobbin thread winding
Program (master)
Phase sensor
USB
X-motor
Thread tension motor
DC motor
Printed circuit board A connection