Janome MC9900 Troubleshooting guide

ADDITIONAL SERVICE MANUAL FOR
MODEL MC9900 (EMBROIDERY UNIT)
• X-MOTOR REPLACEMENT
• Y-MOTOR REPLACEMENT
• PRINTED CIRCUIT BOARD S1 REPLACEMENT
• PRINTED CIRCUIT BOARD S2 REPLACEMENT
• EMBROIDERY UNIT DETECTING SWITCH REPLACEMENT
• FILM REPLACEMENT
• X-SENSOR REPLACEMENT
• Y-SENSOR REPLACEMENT
• X-BELT REPLACEMENT
• Y-BELT REPLACEMENT
• PARTS LIST (EMBROIDERY UNIT)

INDEX
Preparation.................................................................................................................... 2-5
 •RemovingY-carriagecover(upper) ......................................................................... 2
 •RemovingX-carriagecoverandEmbroideryunitcover....................................... 3-5
Replacing X-motor........................................................................................................... 6
Replacing Y-motor ...................................................................................................... 6-11
 •RemovingY-carriagecover(lower)....................................................................... 6-7
 •RemovingFilm ........................................................................................................ 7
 •RemovingFilmguides............................................................................................. 8
 •RemovingY-carriage ............................................................................................ 8-9
 •RemovingY-motor ............................................................................................ 10-11
Replacing Printed Circuti Board S1............................................................................. 12
Replacing Embroidery Unit Detecting Switch ............................................................ 12
Replacing Film............................................................................................................... 13
Replacing X-sensor.................................................................................................. 14-15
Replacing X-belt ............................................................................................................ 16
Replacing Printed Circuit Board S2............................................................................. 17
Replacing Y-sensor ....................................................................................................... 17
Replacing Y-belt............................................................................................................. 18
Y-Carriage Adjustment (Backlash of Y-carriage)........................................................ 19
• Attaching Guide bars to carriage unit.......................................................... 20-21
PARTS LIST ............................................................................................................... 22-25

2
MC 9900
zPush down the carriage arm release lever q.
Extend the carriage arm. Swing out the carriage arm
until it locks in fully extended position.
q
xRemove the setscrew w.
cSlide the carriage in the direction of the arrow.
Remove the setscrew e.
vRemove the Y-carriage cover (upper).
e
Preparation
Remove Y-carriage cover (upper), X-carriage cover
and Embroidery unit cover before replacing to access
carriage parts.
•Removing Y-carriage cover (upper)
w

3
MC 9900
bRemove the setscrews r(3 pcs.).
r
nRemove the X-carriage cover (unit).
mRemove the setscrews t(3 pcs.).
t
•Removing X-carriage cover and Embroidery unit
cover
tt
t
t

4
MC 9900
,Turn the embroidery unit upside down.
Remove the setscrews y, uand i.
uu
i
.Turn the embroidery unit again.
Push down the carriage arm release lever q.
Retract the carriage arm to the stored position.
q
⁄0 Move the carriage arm as far as it goes in the
direction of arrow o.
⁄1 The rounded part of the carriage arm !0 should
meets the hole of the embroidery unit cover !1.
o
!0
!1
u
y

5
MC 9900
⁄2 Remove the embroidery unit cover (unit).
⁄3 Position the flexible cable !2 under the guide plate !3
so the cable will not be damaged when moving.
⁄4 Move the carriage arm in the direction of arrow !4.
⁄5 Push down the carriage arm release lever q.
Extend the carriage arm.
To attach the Y-carriage cover (upper), X-carriage cover
and Embroidery unit cover, follow the above procedure
in reverse.
!3
!2
!4
q

6
MC 9900
Replacing X-motor
•RemovingX-motor
zDisconnect the connector from printed circuit board
S1.
Pry up the lock tab of the connector with a precision
driver and pull out the brown e, orange qand red
wcords.
w
q
e
Precision screwdriver
xRemove the setscrews rto remove the X-motor.
•AttachingX-motor
Follow the above procedure in reverse.
Replacing Y-motor
•Removing Y-carriage cover (lower)
zRemove the setscrew q.
w
xTurn the embroidery unit upside down.
Remove the setscrews w(3 pcs.).
w q e
r
r
q
NOTE:
The colors of the cords may differ from actual
products.

7
MC 9900
cRemove the Y-carriage cover (lower).
•Removing Film
vRemove the setscrews e(2 pcs.) on the film holder.
e
bRemove the film holder and the film.

8
MC 9900
•Removing Film guides
nRemove the setscrews r(4 pcs.) on the film guides.
mRemove the setscrews t(2 pcs.) on the film guides.
tt
•Removing Y-carriage
,Pull the cable in the direction of arrow yto
disconnect the flexible cable from the printed circuit
board S1.
.Remove the setscrews u(2 pcs.).
u
y
r r
r r
Fig.1
!0 !0
!0 !0

9
MC 9900
⁄0 Remove the setscrew i.
i
⁄1 Remove the setscrew o.
⁄2 Remove setscrews !0 (4 pcs.) (see fig.1 on page 8).
Remove the Y-carriage.
o
!0
⁄3 Pull out the guide bars !1 and !2 from the Y-carriage.
To attach the guide bars to the carriage, follow the
procedure in page 20.
!1 !2

10
MC 9900
•Removing Y-motor
⁄3 Remove the guide bars (X2) from the Y-carriage.
Loosen the hexagonal socket screw !3.
!3
!5
⁄4 Slide the stopper !4 in the direction of arrow to
access the setscrew !5.
Remove the setscrew !5.
⁄5 Remove the setscrew !6, !7, !8, !9 and @0.
!4
!6
!9
!7
!8
@0

11
MC 9900
⁄6 The Y-motor @1 is separated from the base @2.
⁄7 Remove the setscrews @3 (2 pcs.).
⁄8 Remove the cord binder and disconnect the
connector @5 from the printed circuit board S2 @4.
⁄9 Pry up the lock tab of the connector with a precision
driver and pull out the red @6, orange @7, brown @8,
brown @9 and red #0 cords.
Remove the Y-motor.
•AttachingY-motor
Follow the above procedure in reverse.
@1
@2
@3
@4
@5
@6@7@8@9#0
NOTE:
The colors of the cords may differ from actual
products.
@3

12
MC 9900
Replacing Printed Circuit Board S1
zRemove the Y-carriage cover (lower) (see pages
6-7).
Remove the setscrew q.
Disconnect the connectors from the printed circuit
board S1.
Remove the printed circuit board S1.
To attach, follow the above procedure in reverse.
ReplacingEmbroideryUnitDetectingSwitch
zRemove the setscrew q.
w
xDisconnect the connector wfrom the printed circuit
board S1.
Remove the Embroidery unit detecting switch.
q
q

13
MC 9900
Replacing Film
•Removinglm
zTo remove the film, remove the setscrews q(2 pcs.)
on the film holder.
xRemove the film holder wand the film.
•Attachinglm
cReplace the film.
Insert the film in the film cover.
vInsert the both edges of the film in the guides e, then
move the film in the direction of arrow.
Tighten the setscrews q(2 pcs.) with the film holder w.
q
w
q
e
e

14
MC 9900
Replacing X-sensor
•Removing X-sensor
zDisconnect the connector from printed circuit board
S1.
Pry up the lock tab of the connector with a precision
driver and pull out the brown e, orange qand red
wcords.
xRemove the setscrew rand tto remove the cord
guide plates.
Remove the tube from the cord guide plate.
w
q
e
Precision screwdriver
e
cRemove the setscrew y.
Remove the X-sensor.
w
q
e
Precision screwdriver
•AttachingX-sensor
vInsert the brown e, orange qand red wcords
to the connector. Be sure that the cords are firmly
locked to the connector.
bAttach the connector to the printed circuit board S1.
Place the tube in the cord guide plates.
y
q
w
r
t

15
MC 9900
,The embroidery unit carriage position is initialized.
The range between A and B should be in the range
of 7.8 mm to 8.2 mm.
If the range between A and B is smaller than 7.8
mm, loosen the setscrew rand move the X-sensor
position to the left.
If the range between A and B is larger than 8.2 mm,
loosen the setscrew rand move the X-sensor
position to the right.
Initialize the embroidery unit again and be sure the
range between A and B is in the range of 7.8 mm to 8.2
mm. If not, repeat the procedure and adjust the range
again.
nAttach the X-sensor.
Tighten the setscrew rtemporarily.
mAttach the embroidery unit to the MC9900.
Insert the machine plug into the power inlet.
Insert the power supply plug into the wall outlet and
turn the power switch on.
8±0.2 mm
A B
y
t
t
y
.Tighten the setscrew rfirmly.
⁄0 The shielding plate tshould be positioned at the
middle of the sensor yas illustrated.
If not, loosen the setscrew uand adjust the sensor
height.
Tighten the setscrew uafter the adjustment.
r
u

16
MC 9900
Replacing X-belt
•Removing X-belt
zRemove the setscrews q(2 pcs.).
Remove the X-belt base plate.
w
w
w
xRemove the setscrews w(3 pcs.).
Replace the X-belt.
•AttachingX-belt
cHook the X-belt to the pulley under the X-belt base
plate.
vHook the X-belt to the pulley of X-motor.
Adjust the X-motor position and tighten the setscrews
w(3 pcs.) temporarily.
Adjust the X-belt deflection to about 3 mm by
pressing the middle of X-belt with approximately 50
grams of pressure.
bTighten the setscrews securely w.
nAttach the X-belt base plate.
Tighten the setscrews q(2 pcs.).
q
3 mm
50 grams of pressure

17
MC 9900
Replacing Printed Circuit Board S2
zRemove the Y-carriage cover (lower) (see pages
6-7).
Remove the setscrew q.
Disconnect the connector and flexible cable from the
printed circuit board S2.
Remove the printed circuit board S2.
To attach, follow the procedure in reverse.
Replacing Y-sensor
•Removing Y-sensor
zRemove the Y-carriage cover (lower) (see pages
6-7).
Disconnect the connector qfrom the printed circuit
board S2 w.
xPry up the lock tab of the connector with a precision
driver and pull out the red e, orange rand brown t.
cRemove the setscrew y.
Remove the Y-sensor.
ert
y
•AttachingY-sensor
zAdjust the Y-sensor height so the shielding plate u
should be positioned at the middle of the sensor i
as illustrated.
Tighten the setscrew yto attach the Y-sensor.
Insert the cords e, rand tto the connector.
Plug the connector to the printed circuit board S2.
xAttach the embroidery unit to the MC9900.
Insert the machine plug into the power inlet.
Insert the power supply plug into the wall outlet and
turn the power switch on.
cThe embroidery unit carriage position is initialized.
The range A (between the edge of Y-carriage LM
guide and the edge of carriage) should be 23.1 mm.
If not, turn the setscrew oand adjust the Y-sensor
position.
If the range A is larger than 23.1 mm, move the
Y-sensor set plate in the direction of “B”.
If the range A is smaller than 23.1 mm, move the
Y-sensor set plate in the direction of “C”
i
u
o
q
q
w
23.1 mm
C
B
A

18
MC 9900
Replacing Y-belt
•Removing Y-belt
zRemove the hexagonal socket screw q.
Slide the stopper in the direction of arrow.
xRemove the setscrews w.
cRemove the setscrews e.
vRemove the Y-belt.
•AttachingY-belt
bAttach the Y-belt.
r
nBe sure that the Y-belt deflection to about 3 mm by
pressing the middle of Y-belt with approximately 30
grams of pressure.
If not, turn the Y-carriage upside down.
Loosen the nut r, and turn the eccentric pin to adjust
the belt tension, then tighten the nut.
mFollow the “removing Y-belt” procedure in reverse.
q
wwww
e
e

19
MC 9900
Y-carriage adjustment
If there is a play at Y-carriage, follow the procedure
below.
zPush down the carriage arm release lever q.
Extend the carriage arm. Swing out the carriage arm
until it locks in fully extended position.
xTurn the embroidery unit upside down.
Remove the cover w.
w
cMove the Y-carriage eunder the hole r.
r
e
vHook a slotted driver to the hole t.
To tighten the carriage, move the fin-shaped metal to
the direction of arrow y.
To loosen the carriage, move the fin-shaped metal to
the direction or arrow u.
Be sure that there is no play at the Y-carriage.
Attach the cover w.
q
u
y
t