ELNA Star Edition User manual

SERVICE MANUAL
MODEL: Star Edition

CONTENTS
WHAT TO DO WHEN .......................................................................................................1-3
SERVICE ACCESS
FACE COVER................................................................................................................ 4
BED COVER.................................................................................................................. 5
FRONT COVER..........................................................................................................6-7
REAR COVER ............................................................................................................... 8
MECHANICAL ADJUSTMENT
PRESSER BAR HEIGHT AND ALIGNMENT................................................................ 9
NEEDLE DROP POSITION......................................................................................... 10
NEEDLE TO HOOK TIMING........................................................................................ 11
NEEDLE BAR HEIGHT ............................................................................................... 12
CLEARANCE BETWEEN NEEDLE AND HOOK POINT ............................................ 13
BACKLASH (LOWER SHAFT GEAR) ......................................................................... 14
FEED DOG HEIGHT ................................................................................................... 15
NEEDLE SWING TIMING............................................................................................ 16
NEEDLE THREAD TENSION...................................................................................... 17
STRETCH STITCH FEED BALANCE ......................................................................... 18
REPLACEMENT AND ADJUSTMENT OF THE NEEDLE THREADER PLATE.......... 19
ADJUSTING BUTTONHOLE LEVER POSITION.............................................................. 20
REPLACING THE ELECTRONIC COMPONENTS........................................................... 21
SELF DIAGNOSTIC TESTS.........................................................................................22-24
REPLACING PRINTED CIRCUIT BOARD A .................................................................... 25
REPLACING PRINTED CIRCUIT BOARD F .................................................................... 26
REPLACING DC MOTOR AND ADJUSTING MOTOR BELT TENSION ........................... 27
REPLACING SWITCHING REGULATOR (UNIT).............................................................. 28
REPLACING STEPPING MOTOR (ZIGZAG).................................................................... 29
REPLACING STEPPING MOTOR (FEED)........................................................................ 30
OILING .............................................................................................................................. 31
PARTS LIST ................................................................................................................. 32-47

1
Condition Cause How to fix Reference
1. Skipping
Stitches
1. Needle is not inserted properly.
2. Needle is bent or worn.
3. Incorrectly threaded.
4. Needle or thread are
inappropriate for fabric being
sewn.
5. Sewing on stretch fabric.
6. Presser foot pressure is too
weak.
7. In appropriate needle bar
height.
8. Inappropriate needle to hook
timing.
9. Inappropriate needle to hook
clearance.
Insert the needle properly.
Change the needle.
Rethread.
Use the recommended sewing needle
and thread.
Use a HA x #11 blue tip needle.
Adjust the presser bar level to make the
pressure stronger.
See mechanical adjustment " Needle bar
height ".
See mechanical adjustment " Needle to
hook timing ".
See mechanical adjustment " Clearance
between needle and hook ".
P. 1 2
P. 1 1
P. 1 3
2. Fabric not
moving
1. Foot pressure foot is too weak.
2. Incorrect feed dog height.
3. Feed dog is in down position.
4. Thread on bottom side of fabric
is jammed up.
5. Feed dog teeth are worn.
Adjust the presser bar level to make the
pressure stronger.
See mechanical adjustment " Feed dog
height ".
Raise the feed dog.
Make sure to bring both needle and bob-
bin threads under the foot when starting
sewing.
Change the feed dog.
P. 1 5
WHAT TO DO WHEN

2
Condition Cause How to Fix Reference
3. Breaking
upper thread.
1. Initial sewing speed is too fast.
2. Thread path is incorrect.
3. Needle is bent or dull.
4. Top tension is too strong.
5. Needle size is inappropriate for
fabric.
6. Needle eye is worn.
7. Needle hole in needle plate is
worn or burred.
Start with medium speed.
Use the proper thread path.
Replace with a new needle.
Adjust top tension correctly.
Use appropriate needle for fabric and
thread in use.
Change the needle.
Repair the hole or replace the needle
plate.
P. 1 7
4. Breaking
bobbin thread.
1. Bobbin holder is incorrectly
threaded.
2. Too much thread is wound on
the bobbin,
3. Lint is stuck inside the bobbin
holder.
4. Thread quality is too low.
5. Thread is jamming around the
bobbin holder.
Set the bobbin thread correctly.
Adjust the position of bobbin winder
stopper.
Clean the bobbin holder.
Change to a high quality sewing thread.
Clear out the jamming thread.
5. Needle
breaks
1. Needle is hitting the needle plate.
2. Needle is bent or worn.
3. Needle is hitting the hook.
4. The fabric moves while the needle
is piercing it, or the needle zigzags
while in fabric.
5. Fabric is being pulled too strongly
while sewing.
See mechanical adjustment " Needle
drop position ".
Change the needle.
See mechanical adjustment " Clearance
between needle and hook ".
See mechanical adjustment " Needle
swing timing ".
Guide the fabric gently while sewing.
P. 1 0
P. 1 3
P. 1 6

3
Condition Cause How to fix Reference
6. Noisy
operation
1. Backlash between hook gear
and lower shaft gear is too
great.
2. Lower shaft gear is loose.
3. Inappropriate belt tension.
4. Not enough oil.
See mechanical adjustment
“backlash (lower shaft gear)”.
Eliminate the looseness.
See part removal and replacement
“driving motor (dc motor)”.
Oil all moving parts.
P. 1 4
P. 2 7
P. 3 1
7. Deformation
pattern
1. Inappropriate feed balance.
2. Inappropriate needle swing
timing.
3. Top tension is too strong.
See mechanical adjustment
“stretch stitch feed balance”.
See mechanical adjustment
“Needle swing timing”.
See mechanical adjustment
“Needle thread tension”.
P. 1 8
P. 1 6
P. 1 7