ELNA eXcellence 780 User manual

SERVICE MANUAL
MODEL: eXcellence 780
First Edition: 3 June 2016

INDEX
Changing External Parts
Face cover...........................................................................................................................................1
Top cover.............................................................................................................................................1
Belt cover ............................................................................................................................................2
Machine base......................................................................................................................................3
Base cover ..........................................................................................................................................3
Bed cover ............................................................................................................................................3
Free arm cover................................................................................................................................ 4-5
Front cover ...................................................................................................................................... 6-7
Rear cover....................................................................................................................................... 8-9
Replacing Electronic Components
Printed circuit board A................................................................................................................. 10-11
Printed circuit board F.......................................................................................................................12
Switching power supply unit..............................................................................................................13
Driving motor.....................................................................................................................................14
Thread tension unit ...........................................................................................................................15
Mechanical Adjustment
Feed dog height ................................................................................................................................16
Needle drop position .........................................................................................................................17
Clearance between needle and tip of the rotary hook ................................................................ 18-19
Hook timing .......................................................................................................................................20
Needle bar height..............................................................................................................................21
Backlash between hook drive gear and lower shaft gear..................................................................22
Upper shaft shield plate position.......................................................................................................23
Upper thread tension.........................................................................................................................24
Tension release mechanism..............................................................................................................25
Replacing Needle threader hook.......................................................................................................26
Needle threader hook position ..........................................................................................................27
Thread drawing lever.........................................................................................................................28
Upper feed dog (1) ............................................................................................................................29
Upper feed dog (2) ............................................................................................................................30
Upper feed dog (3) ............................................................................................................................31
Buttonhole lever ................................................................................................................................32
Thread cutter.....................................................................................................................................33
Presser bar lifter position ..................................................................................................................34
Presser foot lifter stopper position (1) ...............................................................................................35
Presser foot lifter stopper position (2) ...............................................................................................36
Automatic presser foot lifter initializing position.................................................................................37
Presser bar height.............................................................................................................................38
Stretch stitch feed balance................................................................................................................39
Needle plate switch ...........................................................................................................................40
Knee lifter..........................................................................................................................................41

1
Changing External Parts
Face cover
To remove:
1. Open the face cover.
Disconnect the connector from the face cover.
Remove the setscrews A.
Remove the face cover.
To attach:
1. Follow the above procedure in reverse.
Setscrew A
Face cover
Top cover
To remove:
1. Raise the carrying handle.
Remove the setscrew B.
Close the carrying handle.
Setscrew B
Top cover
2. Open the top cover.
Remove the setscrews C and D.
3. Raise the carrying handle and remove the top cover.
To attach:
1. Follow the above procedure in reverse.
Carrying handle
Setscrew C Setscrew D
Connector

2
Changing External Parts
Belt cover
To remove:
1. Remove the caps from the belt cover.
Remove the setscrews A and B.
Setscrew A
2. Loosen the setscrew C.
Setscrew B
Setscrew D
Belt cover
Setscrew C
3. Loosen the setscrew D.
Remove the belt cover.
To attach:
1. Follow the above procedure in reverse.

3
Changing External Parts
Machine base
To remove:
1. Remove the setscrews A and B .
2. Remove the machne base.
To attach:
1. Follow the above procedure in reverse.
Setscrew B
Setscrew A
Setscrew A
Setscrew B
Machine base
Base cover
To remove:
1. Remove the extension table.
Remove the setscrews A.
2. Remove the base cover.
To attach:
1. Follow the above procedure in reverse.
Bed cover
To remove:
1. Remove the extension table.
Remove the setscrews C.
2. Remove the bed cover.
To attach:
1. Follow the above procedure in reverse.
Setscrew A
Setscrew A
Setscrew A
Setscrew A
Machine base
Setscrew CSetscrew C Bed cover

4
Free arm cover
To remove:
1.
Remove the machine base and base cover (see page 3).
Press the needle plate release lever to remove the
needle plate.
Changing External Parts
2. Remove the pin.
Remove the bed cover (see page 3).
3. Loosen the setscrew A.
Pin Bed cover
Needle plate
Free arm cover Needle plate release lever
Setscrew A

5
4. Remove the free arm cover from the free arm while
unlocking the hook A (front side of the free arm) and B
(inside of the machine base) from the free arm.
5. Slide the free arm cover to the left.
Remove the free arm cover.
To attach:
1. Follow the above procedure in reverse.
Hook B
Hook A

6
Changing External Parts
Setscrew A Setscrew A Front cover
To remove:
1. Remove the top cover, belt cover, base cover, machine
base and free arm cover (see pages 1-5).
2. Loosen the setscrews A .
Setscrew C 3. Loosen the setscrews B and C.
4. Loosen the setscrew D.
Setscrew B
Setscrew D
(Bottom of the machine)
(Top of the machine)

7
5. Loosen the setscrew E.
Hooks
Setscrew E
6. Unlock the hooks from the front cover.
Remove the connectors from the circuit board A.
Remove the front cover.
To attach:
1. Follow the above procedure in reverse.
Refer to page 7 for locating connector posts.

8
3. Loosen the setscrew A.
Changing External Parts
4. Loosen the setscrew B.
Setscrew A
Setscrew B
Rear cover
To remove:
1. Remove the top cover, mahine base, base cover and
free-arm cover (see pages 1, 3 and 4-5.)
2. Open the face cover.
Disconnect the connector from the face cover.
Close the face cover.
Face cover
Connector A

9
Setscrews C 5. Remove the setscrews C and D.
Unlock the rear cover hook from the front cover.
6. Disconnect the connectors A and B from the sockets.
Cut and remove the cord tie as necessary.
Remove the rear cover.
To attach:
1. Follow the above procedure in reverse.
Setscrews D
Connector A
Connector B
Cord tie

10
Printed circuit board A connection
Replacing Electronic Components
Printed circuit board A
NOTE:
Do not disconnect the connectors by pulling on cord.
To disconnect the connectors, grasp the connector, not
the cord.
To remove:
1. Remove the front cover.
2. Grasp the connector directly with your fingers and pull.
Do not pull the lead wire, as this may damage the
contact sleeve inside the connector.
Remove the setscrews and printed circuit board A.
To attach:
1. Follow the above procedure in reverse.
Be sure that the connector post on the printed circuit
board to which it is connected.
Position the connector correctly, then push it straight
down until it locks in place.
Setscrew
Setscrew
q
w e rty
u
i
o
!0
!1
!2
!3
!4
!6
!5
!7!8!9
@0
@8
@7
@6
@5
@4
@3
@2
@1
Bobbin winder switch
LCD
Touch panel
Program (Slave)
Printed circuit board L1*
Printed circuit board L2
Printed circuit board L3 (red)
Slide volume
Printed circuit board F
Presser foot lifter sensor*
BH sensor*
Upper thread sensor*
Knee lifter sensor
Power switch
Thread cutter motor
Remaining bobbin thread detecting sensor
Feed motor
Remaining bobbin thread detecting motor (green)
Needle plate detecting sensor
Drop feed detecting sensor (brown)
DC motor
Presser foot lifter motor
Thread tension motor
Zigzag motor
USB
Foot control & Thread cutter switch jack
Phase sensor
Program (Slave)
q
w
e
r
t
y
u
i
o
!0
!1
!2
!3
!4
!5
!6
!7
!8
!9
@0
@1
@2
@3
@4
@5
@6
@7
@8

11
@4!2 @3
Bobbin winder switch (blue)
LCD
Touch panel
Program (Slave)
Printed circuit board L1
Printed circuit board L2
Printed circuit board L3 (red)
Slide volume
Printed circuit board F
Presser foot lifter sensor
BH sensor
Upper thread sensor
Knee lifter sensor
Power switch
Thread cutter motor
Remaining bobbin thread detecting sensor
Feed motor
Remaining bobbin thread detecting motor (green)
Needle plate detecting sensor
Drop feed detecting sensor (brown)
DC motor
Presser foot lifter motor
Thread tension motor
Zigzag motor
USB
Foot control & Thread cutter switch jack
Phase sensor
Program (Slave)
Lamp relay cable
q
w
e
r
t
y
u
i
o
!0
!1
!2
!3
!4
!5
!6
!7
!8
!9
@0
@1
@2
@3
@4
@5
@6
@7
@8
A
t!0!1 @2 q u @7
iA
A
@6 !4@1@0 @5 !3!5!9
!8 !7 !6
y
* Connectors tand !0, !1 and !2 are very similar.
Be sure to position the connector to the correct place.
Connect the connectors to the corresponding connector posts on the
circuit board A (see page 10).
Front cover (rear side)
Machine body
Foot control
connector
Printed circuit
board A
Slide volume
Printed circuit
board F
o

12
Printed circuit board F
To remove:
1. Remove the front cover (see page 6-7).
2. Disconnect the connectors from the circuit board A (see
page 10-11).
3. Remove the CS rings.
4. Remove the setscrews, and the circuit board F.
To attach:
1. Follow the above procedure in reverse.
Replacing Electronic Components
Printed circuit
board F
Setscrew
CS rings
CS rings
Setscrew

13
Switching power supply unit
To remove:
1. Remove the top cover, the belt cover and the front
cover (see page 1, 2 and 6-7).
2. Loosen the setscrew A. Remove the cord guide plate.
Replacing Electronic Components
Switching power supply
Setscrew A
Setscrew B
Power
supply
connector
(cord)
Cord guide plate
Setscrew B
Power supply connector (cord)
Foot control connector A
3. Disconnect the power supply connector from the
switching power supply unit.
4. Disconnect the foot control connector A.
5. Remove the setscrews B (3 pcs.), and the switching
power supply.
To attach:
1. Follow the above procedure in reverse.
Switching power supply

14
200 g pressure
5 mm
Setscrew
Setscrew
Driving motor
To remove:
1. Remove the belt cover, the top cover and the front
cover (see pages 1, 2 and 6).
2. Remove the setscrews (2 pcs) and the motor belt.
Remove the driving motor.
Replacing Electronic Components
To attach:
1. Attach the driving motor. Tighten the setscrews
temporarily.
2. Adjust the motor belt deflection to about 5 mm by
pressing the middle of the motor belt with your finger
with approximately 200 grams of pressure.
3. Tighten the setscrews securely.
4. Attach the front cover, the top cover and the belt cover.
Motor belt

15
Replacing Electronic Components
Thread
tension
unit
Setscrew A Thread tension unit
To remove:
1. Remove the belt cover, top cover and the front cover
(see pages 1, 2 and 6-7).
2. Remove the setscrews A and B.
3. Cut the cable tie A. Be careful not to cut the cables.
Remove the setscrew C and cords from the cable tie B.
Remove the thread tension unit.
Setscrew B
Cable tie A Setscrew C
Cable tie B
To attach:
1. Follow the above procedure in reverse.
2. Check the upper thread tension (see page 24).

16
Mechanical Adjustment
Nut
Setscrew A Adjusting screw B
Presser foot
0.8 – 0.9 mm
Surface of
needle plate
Feed dog
Hexagonal socket screw I
Setscrew D
Threaded hole C
Feed dog height
When the foot pressure dial is at “7” and the presser foot A is lowered, the highest position of the feed dog should be 0.80
to 0.90 mm from the surface of the needle plate.
Adjusting screw B
Threaded hole C
Setscrew A Setscrew D
Adjustment 1:
1. Attach the zigzag foot A. Remove the base cover and
bed cover (see page 2-3).
2. Turn the power switch ON. Adjust the foot pressure to
the maximum (AUTO+4) in the ordinary sewing setting
mode. Adjust the stitch length to the maximum (5.0).
3. Press the presser foot lifter button to lower the presser
foot.
4. Turn the handwheel toward you to raise the feed dog
to its highest position.
5. Loosen the setscrew (A).
6. Loosen the nut with a socket wrench. Turn the
adjusting
screw and adjust the feed dog hight to 0.85 mm.
7. Tighten the nut and setscrew (A).
8. Turn the handwheel and check that the feed dog teeth
are pararell with the surface of the needle plate. If not,
follow the adjustment procedure below.
Adjustment 2:
If the feed dog is not parallel to the surface of the needle
plate at its highest position, make the adjustment as
follows:
* For this adjustment, a hexagonal socket screw 4x6 I,
part No. 000111108 is required.
1. Insert a hexagonal socket screw I, part no. 000111108
into the threaded hole (C) until it stops.(use an Allen
wrench of 2 mm width across flats).
2. Turn the setscrew D (left hand screw) clockwise to
loosen it.
3. Turn the hexagonal socket screw I until the feed dog is
parallel with the surface of the needle plate.
4. Tighten the setscrew D by turning it counterclockwise.
5. Remove the hexagonal socket screw I.
6. Attach the bed cover and base cover.
After finishing adjustment, return the foot pressure to
AUTO.

17
To adjust:
1. Attach the #14 needle. Turn the power switch ON and
select straight stitch #1.
2. Check the clearance between the needle and the side
of the needle hole when the needle drop position is
set at "0.0" and "9.0" respectively.
Mechanical Adjustment
Needle drop position
When the straight stitch is selected, the needle should be positioned in the center of the needle plate hole.
When the needle drop position is set at "0.0" and "9.0", the clearance between the side of the needle and the needle
hole should be 0.2 mm or more.
Eccentric
pin
Needle hole
0.2 mm or more0.2 mm or more
A = B
Hexagonal
socket screw
Pin
Eccentricity
“9.0”
“0.0”
Needle drop position "4.5"
Fig. 1
3. If the clearance is less than 0.2 mm, adjust it as
follows.
Loosen the hexagonal socket screw (use an Allen
wrench of 2 mm width across flats).
4. Turn the eccentric pin to get 0.2 mm or more clearance.
The direction of eccentric pin should be as shown.
Tighten the hexagonal socket screw.
Attach the straight needle plate and check if the
needle drops in the center of the needle hole. Check
the hook timing and the needle bar height after this
adjustment (see page 20 and 21).

18
Test pin
Tip of hook
-0.1 to +0.05 mm
Left needle
position
Right needle
position
Clearances A and B must be even
A
B
Mechanical adjustment
Clearance between needle and tip of the rotary hook (method 1)
The clearance between the needle and the point of hook should be -0.1 to +0.05 mm.
Needle bar
supporter
Hexagonal
socket screw
1. Remove the top cover (see page 1).
2. Remove the presser foot, the needle plate and the
bobbin holder.
3. Attach the test pin.
4. Turn the power switch ON while pressing the Start/
Stop button and the Reverse stitch button. The LCD
shows the factory setting mode.
Press "Bobbin" key. The machine will set the zigzag
width at maximum.
5. Turn the handwheel toward you until the tip of the hook
comes behind the test pin.
6. Loosen the hexagonal socket screw (use an Allen
wrench of 2 mm width across flats) and move the
needle bar supporter in the direction of the arrow so
the test pin just touch the tip of the hook. Tighten the
hexagonal socket screw.
7. Attach the bobbin holder and the needle plate. Check
the needle drop position. The needle drops in the
center of the needle plate hole as shown.
If the clearances A and B are not even, adjust the needle
drop position first and then adjust the clearance between
the needle and the tip of the hook by the method (2) on
the next page.