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 The mains plug must be withdrawn before making any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.

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 9/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Sewing/
Darning
Mechanism
When switching from
sewing to daring (dropping
the feed dog) the feed dog
should rise on lower.
• Feeding problem
• Feed dog can't be
lowered
Clean, oil, adjust
INSTRUCT10N IN
PART 2.13
Free Hand
System (FHS)
The system raises and
lowers the presser foot. With
the presser foot lifter lever in
the up position it releases the
lifter lever.
The top tension is released.
With late Models 930 the
feed dog drops as well.
The shaft in the base plate is
play free and the knee lifter
lever is held securely inside
that shaft.
• Hand lifter lever
cannot be lowered
• Presser foot cannot
be lifted
• Knee lifter lever
hangs loose.
• Knee lifter is not held
securely in the
machine.
• Feed dog does not
lower. (Late Model
930 only)
• Eliminate play in
the lifter shaft.
• Replace knee lever
if the lever does
not stay in shaft
securely.
• Replace tension
spring behind
motor if lever
hangs loose.
(Model 830)
• Clean, lubricate
and adjust drop
mechanism (Model
930) check the
distance of 38mm
between the collar
and the coupling
half.

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 10/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Model 930
LED/Switching
operation (red/
green stitches)
When selecting either “red
or green” stitches the knob
has to stay securely in place
during machine operation.
The LED red & green
indicator is changing on top
and bottom.
• No definite switching
operation between
red/ green
• During operation the
change over knob
rocks from left to
right.
• No LED indication
Clean micro switch
located on the 930
PCB
Update spring support
Replace PCB's if
necessary.
Check plug
connections at L-Print
INSTRUCTI0N IN
PART 2.10
Model 830
Feed Dog
Eccentric
The feed dog eccentric
controls the feed dogs up
and down motion.
• Loud noise in free
arm
• Feeding problem
• Inconsistent
buttonhole
• The plastic eccentric
is cracked or missing.
Check if the nylon
eccentric shows
hairline cracks.
Check if the
follower/fork wore a
groove into the
eccentric.
Replace if needed
INSTRUCT10N IN
PART 2.1
Model 930
Feed Dog
Eccentric and
feed dog drive
The feed dog eccentric
controls the feed dogs up
and down motion.
The linkage must move
freely, must be play free and
lubricated.
• Loud noise in free
arm
• Feeding problem
• Inconsistent
buttonhole
Disassemble the
driving mechanism.
Clean and lubricate the
linkages.
Replace parts if play is
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 11/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Foot Control
Non-Electronic
Type: 213
The foot control controls the
speed of the machine. As the
foot control is pressed
hundred of internal carbon
discs are pressed together,
reducing the resistance, thus
gradually increasing the
machines speed.
Warning:
Make sure the (T) thermo
switch has been installed.
.
• Hot controller when
sewing on slow speed
• Cuts out after a
certain time when
sewing at slow speed.
• Speed hesitation
when controler is
pushed.
Install thermo safety
switch if (T) is
missing.
Replace rheostat
Install cooling plate if
needed.
Adjust start and full
speed.
When sewing at slow
speed use the min/max
switch. This will
reduce the heat
generation inside the
foot control.
Foot Control
Electronic
Type: 232/290
The foot control controls the
speed of the machine. When
the foot control is pushed an
audible micro switch click
can be heard, the machine
runs smoothly at the speed
of 180 rpm/min. As the
control is pressed further,
the speed should gradually
increase until the machine
reaches the top speed of
1050 rpm.
• Inconsistent start
speed
• Machine only runs at
slow speed.
• Machine only runs at
fast speed
• Machine stutters at
start speed.
• The machine
hesitates when foot
control is pushed.
Adjust start speed by
turning the potentio-
meter.
Replace broken carbon
pins
Replace circuit board.
(See website for
board repair
instructions)
Clean the resistor
plate.
232

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 12/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Foot Control
Electronic
Type: 347/366
The foot control controls the
speed of the machine. As the
control is pressed, the speed
should gradually increase
until the machine reaches the
top speed of 1050 rpm.
When the foot control is
released the machine stops
instantly with the take up
lever stopping at the highest
point. With some foot
controls while pushing the
control with the heel the
needle stops down.
• The machine
hesitates when foot
control is pushed.
• The machine does
not run at all.
• No gradual speed
increase.
• Needle stop kicks in
when it should not.
Clean the resistor plate
Replace broken carbon
pins
Replace the resistor
plate.
Off/Max/Min
Switch
Check the different switch
operation on the older
models 730, 830 (non-
electronic) and the models
930-910.
• Does not switch to
slower or higher
speed.
Models 730/830
Check if diode is
plugged in bottom of
Max/Min switch.
Check if the motor is
wired correctly.
Models 930/910:
Repair circuit board
930

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 13/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Motor
bracket/Motor
housing
It supports the motor and the
printed circuit board.
Model 930 the clips and the
bracket holding the motor
secure have a tendency to
become bridle over time
• Loose belt tension,
• Loud belt
transmission noise
Replace the faulty part

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 14/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Motor The motor drives the
machine. Electronically
controlled motors usually
allow increasing the piercing
power of the needle while
maintaining the same speed.
The motor is quiet running
and powerful.
• Motor does not run
• Slow and sluggish
• Motor is getting hot
• Excess motor noise
• Arcing around
armitor
The Model 730 and
830 brushes need to be
checked frequently.
The Model 930 and
910 brushes and the
armitor do not need to
be checked, unless the
machine does not work
and you suspect the
motor.
Clean armitor with
green armitor cleaner.
Check or replace
motor brushes (always
check and replace both
at the same time).
Replace brushes when
½ worn down.
Lubricate each side of
the bushings. (all
motors)
Warning if the Model
730/830 brushes are
worn out, the spring
behind the brushes will
not stop and will
damage the armitor.

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 15/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Driving belts The belts transmit the power
from the motor to the
machine. They have 100%
traction and are quiet.
• No needle
penetrating power
• Squeaking sounds
from motor side.
• Binding machine
Check for belt wear
and replace if
necessary.
Adjust the belt tension.
Squeaky belts can be
quieted by running the
belts though a bar of
soap.

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 16/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Belt
transmission
Transmits the motion from
the motor to the hand wheel.
• Clinging sound from
hand wheel side.
Clean and lubricate the
step pulley shaft.

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 17/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Model 730/830
Hand wheel
and hand
wheel release.
Model 930
automatically
releases the
hand wheel
when the
winder cover is
lifted.
The hand wheel aids the
positioning of the needle and
the take up lever.
The hand wheel release
disconnects the driving
motor/hand wheel from the
machine for winding
bobbins. When the hand
wheel is release the needle
should remain stationary
while winding the bobbin.
When the hand wheel is
engaged the needle should
have full penetrating power.
Check for any thread that
may be wrapped around the
step pulley and handwheel.
• Loud low rattling
sound transmission
from hand wheel.
• The needle moves
when the hand wheel
is released.
• The needle has no
penetrating power.
• Remove hand
wheel
• Remove thread
behind wheel.
• Clean the center of
the handwheel and
the flange from the
main shaft. Note:
Hand wheels with
internal metal
bushing need to be
lubricated, hand
wheels without
bushing need to
run dry.
• Adjust belt tension.
• Adjust hand wheel
release mechanism

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 18/32 2003 Bernina of America Inc
Part Description Possible
Malfunction
Repair
Instructions
Picture
Hand wheel
and needle stop
up and down
(930)
The hand wheel aids the
positioning of the needle and
the take up lever.
When the machine is
stopped from full speed, the
take up lever should stop at
the highest point.
When the machine is
stopped from slow speed the
lower part of the take up
lever should be above the
edge were the top cover
meets the upper frame.
For machines with the
needle stop down feature
press the rear of the foot
control, the needle should
stop down in the needle
plate.
• Wobbling hand
wheel.
• Inconsistent needle
stopping position, up
or down.
• Loud and erratic
stopping action
• No release action
after the machine
comes to a complete
stop. (Hand wheel
binds)
• Remove thread
behind wheel.
• Check if hand
wheel is mounted
correctly.
• Replace damaged
hand wheel.
• Remove hand
wheel, black sleeve
and spring.
• Check main shaft
flange, spring and
sleeve for wear,
replace if needed.
• Remove grooves in
flange with
polishing cloth.
• Clean and lubricate
flange, spring and
sleeve.
• Check flange
screw for tightness.
• Replace notched
segment with new
style and adjust
INSTRUCTI0N IN
PARTS 3.2, 3.3