Bernina 700 Installation guide

BERNINAAdvanced Technical Training
For the use of authorized BERNINA dealers only Last Revised 5/11/2005
2003 Bernina of America Inc
Service Procedure 700/800/900 Series

BERNINASafety Instructions
For the use of authorized BERNINA dealers only Last Revised 5/11/2005
Safety Regulation/Warning 2003 Bernina of America Inc
SAFETY REGULATION – WARNING
Please refer to the Safety Regulation information for each machine in the Bernina Factory Service Manual and the Safety Regulation
information in the My Bernina Guide Book.
All electrical and electronic components operate at dangerous voltages. The mains plug must be withdrawn before making any
adjustments to the machine. Wait about 30 seconds after removing the plug (capacitor discharge).
If two pieces of insulating material (i.e. shoe sole and floor) rub together, there can be a buildup of static electricity. Should this static
charge be discharged through electronic components, they can be seriously damaged. One of the most effective ways of conducting
these charges away is by grounding. This can be accomplished by using the grounding mat and wrist strap provided by Bernina of
America, Inc.
This manual is not intended to be complete and to replace any original factory manuals. Its purpose is solely to educate Bernina
dealers and their technician. For any additional factory settings, please refer to the corresponding factory service manual.
THIS MANUAL IS COPYRIGHTED AND REMAINS THE PROPERTY OF BERNINA OF AMERICA, INC.
PUBLICATION, DUPLICATION OR PROVIDING INFORMATION TO A THIRD PARTY WITHOUT OUR
WRITTEN APPROVAL FROM BERNINA OF AMERICA, INC. IS PROHIBITED.
BERNINA OF AMERICA, INC.
3702 PRAIRIE LAKE COURT
AURORA, IL 60504

BERNINAServicing Procedure for Series 700-900
For the use by Authorized BERNINA Dealers Only Last Revised 5/11/2005
Service Procedure 700-900.doc Page 1/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Machine Check for overall physical
appearance,
damaged/scratched cover,
bent or broken spool pins,
button, knobs and levers.
Scratches in paint can
be polished or touched
up with touch-up
paint.
Broken parts are
replaced.
Machine Run machine if possible to
get a feel for the overall
conditions. Change stitch
length, stitch width, needle
position, select different
stitches and features, check
sewing light etc.
Note your findings and
proceed.

BERNINAServicing Procedure for Series 700-900
For the use by Authorized BERNINA Dealers Only Last Revised 5/11/2005
Service Procedure 700-900.doc Page 2/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Service
Procedure
In order to follow a
systematic service procedure
we recommend to follow the
sequence outlined in this
manual

BERNINAServicing Procedure for Series 700-900
For the use by Authorized BERNINA Dealers Only Last Revised 5/11/2005
Service Procedure 700-900.doc Page 3/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Clean and
lubricate the
entire machine
Foot control
and power
cord
Check foot control cover for
physical damage, check foot
control cord for damage
Check power cord and plug
for damage.
Consumer safety hazard.
Inconsistent speed
control
Machine hesitation
Replace foot control
covers and cord.
Replace power cord.

BERNINAServicing Procedure for Series 700-900
For the use by Authorized BERNINA Dealers Only Last Revised 5/11/2005
Service Procedure 700-900.doc Page 4/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Accessories Check the condition of the
accessories such as presser
feet and bobbins.
Replace the individual
accessory
Free arm cover
plate
The cover plate should fit
tightly on top of the free arm
• Inconsistent
buttonholes.
• Inconsistent fabric
feed.
• Hollow sound
• Tape used as a fabric
guide too close to the
presser foot can
cause fabric feed
retardation.
With the cover
mounted and using the
knuckles of you finger,
tap all the way around
the edges of the cover.
If the cover does not
fit flush with the arm a
clanking sound can be
heard. Adjust the
cover by aligning it
with the top of the free
arm and the locking
mechanism.
Remove tape from free
arm cover and suggest
to the consumer to use
a presser foot with a
fabric guide instead.

BERNINAServicing Procedure for Series 700-900
For the use by Authorized BERNINA Dealers Only Last Revised 5/11/2005
Service Procedure 700-900.doc Page 5/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Needle Plate The needle plate should be
smooth and polished,
especially around the stitch
hole.
• Thread breaking or
shredding
• Looping stitches
• Skipped stitches
• Fabric feeding issues.
• Difficulties sewing
lightweight and
elastic fabrics.
Polish or replace the
needle plate. When
polishing the plate be
careful not to enlarge
the stitch hole.
Feed Dog At stitch length maximum
the feed dog should not
touch the front or rear at its
full forward and reverse
stroke.
The feed dog must to be
parallel and in the center of
the needle plate
The teeth should be sharp
and complete.
Both rows of feed dog teeth
have to be the same height.
• Buttonhole feeding
problem
• Loud knocking sound
on longer stitch
length
• Feeding problems
Adjust or replace feed
dog.
INSTRUCTION IN
PART 2.2
Feed dog
support and
driving
mechanism
The feed dog, feed dog
support and feed dog driving
shaft should move bind and
play free.
• Buttonhole feeding
problem
• Knocking sound on
longer stitch length
• Feeding problems
Tighten the feed dog
support mechanism.
Remove the base plate
and eliminate the play
in the drive shaft by
tightening the collar
against the bushing.

BERNINAServicing Procedure for Series 700-900
For the use by Authorized BERNINA Dealers Only Last Revised 5/11/2005
Service Procedure 700-900.doc Page 6/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Shuttle Race
Cover
Check for wear and tear
created by the hook and for
burrs created by the needle
and hook. The race cover
has to be smooth, and should
fit flush against the shuttle
race.
• Skipped stitches
• Looped stitches
• Thread breaking
• Hook noise
Adjust or replace
Hook The hook and hook tip
should be sharp, smooth and
polished.
Check hook for wear marks
at the running surface.
• Skipping stitches
• Looping stitches
• Thread breaking
• Thread jamming
• Thread fraying
• Hook noise
Sharpen and polish
hook point. Be careful
not to change the
shape of the hook tip.
If the hook is dropped
on the tip the tip might
be broken off or the tip
is bent, replace hook.
Bobbin Case
The bobbin case should be
smooth, polished and free of
corrosion.
There should be no lint
between the bobbin case and
the tension spring.
The tension spring creates
equal tension when the
thread released on the left
and right hand side of the
spring.
• Inconsistent tension • Adjust tension and
tension spring for
consistent and
equal tension.
• Polish the bobbin
case body
• Tighten the inside
and the spring
securing screw
(not the tension
adjusting screw)

BERNINAServicing Procedure for Series 700-900
For the use by Authorized BERNINA Dealers Only Last Revised 5/11/2005
Service Procedure 700-900.doc Page 7/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Bobbin Case
(cont.)
• Adjust bobbin case
tension.
• Make sure a
genuine Bernina
bobbin case is
used.
Shuttle Race The race should be smooth,
clean and lubricated. Check
for scarring marks or
particles embedded into
recess and the running
surface.
• Loud hook noise
Using a toothpick or
an ear swab, remove
the particles from the
running surface and
the recess.
Replace if the race is
worn or the grooves
are too excessive.

BERNINAServicing Procedure for Series 700-900
For the use by Authorized BERNINA Dealers Only Last Revised 5/11/2005
Service Procedure 700-900.doc Page 8/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Driver The driver pushes the hook
in an oscillating motion.
When the driver changes
directions the spring should
absorb the impact of the
hook’s momentum. The
driver is equipped with
needle guards/deflectors.
The driver should be free of
radial play.
• Skipped stitches
• Noise in hook area
• Looping stitches
• Thread breaking
• Thread fraying
Remove the driver;
clean the driver teeth,
behind the driver
spring, driver shaft,
bushing and rack.
Remove any burrs
from spring and driver
body.
Check driver spring
for:
Hair line creaks and
if spring has play on
both sides.
Before placing the
driver back in to the
machine lubricate the
driver shaft.
Also make sure to
maintain a 0.3mm
thread passing
clearance between the
hook and the driver
and no play exists
between rack and
driver. To eliminate
play carefully rotate
the rack counter
clockwise.