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