Bernina activa 125 User manual

1
Attention!
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 The mains plug must be withdrawn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).
The service manual is intended to help with small repairs
and adjustments. The instructions lay no claim to comple-
teness. They are not suitable for a complete assembly or
disassembly procedure.
Important:
To enable the work described to be performed correctly,
the sewing machine must be in good mechanical and
electrical condition (running smoothly, properly oiled and
all plugs in position). When the adjustments are carried
out in the correct order, the machine will sew perfectly.
When doing any service on a machine always use the
original accessories that were delivered with the machine,
or were purchased afterwards. These are the following:
– Mains cable
– Foot control unit
– Buttonhole foot
– Bobbin case with bobbin
– Other accessories
This manual is copyrighted. It is given to the recipient
personally. Without our approval it is forbidden to
reproduce, publish or in any other form be distributed,
memorised on a magnetical, electronical, mechanical
system. Further, information to a third party without our
written approval is prohibited.
This manual is an ever changing document. The recipient
is responsible for updating the information which he will
receive from Fritz Gegauf Ltd. Switzerland.
Impressum
Author: P. Kenyon, V. Häseler
Layout conception: Melzer-Müller id, Kreuzlingen
Typesetting /DTP: Silvia Bartholdi
Print: Bodan AG, Kreuzlingen
Safety Regulations

2 Contents
Technical data 3, 4
Service Panel 4
Tools & Gauges 5
Electronic
•Description 6
•Block diagram 7
•L-Print 8
•S-Print 9
•Diagnosting 10
•Powering of the stepping motors 10
•Bevore service or repair work carried out 10
•Protection of electrical components against
electrostatic discharges 10
Service Programme
•Start/Stop the service programme 11
In Basic Service Programme
•Configuration 11
•Foot control unit 11
•P-Print (Positioning) 12
•Bobbin winder motor 12
As a programme
LCD Function of the LCD display 13
No.1 Sewing-off 13
No. 2 Forward/Reverse feed compensation 13, 14
Test Buttonhole 14
No. 3 Automatic darning 15
No. 4 Software version 15
No. 5 Number of hours sewn 15
No. 6 Maximum speed regulation 16
No. 7 Stepping motor test stitch width 16
No. 8 Pinning position of both stepping motors 17
No. 9 Stepping motor test stitch length (SL) 17
No. 10 Displaying the actual speed 18
No. 11 Displaying the factor of speed regulation 18
No. 12 Start/Stop function 19
No. 13 Testing both stepping motors (SL and SB) 19
Testing ribbon cables 20
Functional inspection 21
Removing covers 22, 23
Cleaning 24
Exchanging parts
•S-Print 25
•Buttonhole sensor 25
•L-Print 26, 27
•Main motor 27
•Stepping motor SB 28
•Stepping motor SL and crank shaft 28
•Bobbin winder motor 29
•Base shaft 29
•Hook race ring 30
•Tension unit 30
•Take-up lever 31
•Main shaft 32
Adjustments
•Belt tension main shaft/main motor 33
•Belt tension main shaft/base shaft 33
•Bobbin winder device 34
•Presser foot fixation 34
•Head frame plate 34
•Presser foot height 35
•Darning foot height 35
•Drive position in the hook race 36
•Distance needle/hook 36
•Needle position zig-zag 36
•Position of synchronisation disc 37
•Feed-dog position in the stitch plate 37
•Height of the feed-dog 38
•Thread passage play 38
•Thread guide plate 39
•Loop lift 39
•Position of Hook/Driver 40
•Needle height 40
•Feed-dog Synchronisation 41
•Basic setting of balance 41
•Knee lifter unit (accessory) 42
•Lower thread tension 42
•Upper thread tension 43
•Adjustment of upper thread tension with a weight 43
•Tension release lever 44
•Thread regulator spring 44
Oiling and Lubrication 45
Sewing-off 46
Cleaning 46
Complaints form 46
Complaints report: Appendix
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3Technical data BERNINA activa series
activa 135
5
0,15
5
5,5
0,23
9
3
1
Yes
Yes
19
5
No
30
Yes
Yes
on screen
Yes
mechanical
Yes
No
Yes
Yes
Yes
Yes
BERNINA
No
optional
Rubber pad
LCD
60 x 40
symbolic
Yes/LED
partly
Yes
Yes
Yes
activa 145
5
0,15
5
5,5
0,23
9
3
1
Yes
Yes
19
19
1
50 (+ 60 charac.)
Yes
Yes
on screen
Yes
mechanical
Yes
Yes
Yes
Yes
Yes
Yes
BERNINA
No
optional
Rubber pad
LCD
60 x 40
symbolic
Yes/LED
partly
Yes
Yes
Yes
Features (Stitches)
Stitch length forwards in mm
Increment in mm
Stitch length reverse in mm
Stitch width in mm
Increment in mm
Needle positions
Buttonhole types
Darning programme
Functions by stitch counter
Buttonhole: length measurement
Total practical stitches
Total decorative stitches
Alphabets and numbers
Total number of stitches
Functions
Automatic basic settings
Optimum settings displayed
Selected stitch function
Clear (clr) button
Balance
Pattern end
Mirror image (lateral)
Permanent reverse sewing
Memory (mem)
Permanent save
Hopper mechanism
Presser foot attachment
Adjustable presser foot pressure
FHS presser foot lifter
Operating controls
Buttons
Screen
Size in mm
Type
Background lighting
Direct stitch/function selection
Stitch width indicator beam
Stitch length indicator beam
Integrated service programme
activa 125
5
0,15
5
5,5
0,23
9
3
1
Yes
Yes
10
5
No
20
Yes
No
on screen
Yes
mechanical
Yes
No
Yes
No
No
Yes
Snap-on
No
optional
Rubber pad
LCD
60 x 40
symbolic
No
partly
Yes
Yes
Yes

activa 125
80W
DC/65W/24V
120–900/min
up & down
*
Yes
Yes
160 x 110 (192)
345
176
307
12V/5W
1 x 5W
7,5 mm
Yes
** Optional
BERNINA-CB
130/705H
130/705H TCN
ca. 9,6 kg
4Technical data BERNINA activa series contd.
Drive unit/power unit
Power max.
Motor
Sewing speed S.p.m.
Needle stop
Needle stop via foot control
* optional with virtuosa foot control
Roll-up foot control cable
Main power switch
Construction/housing
Through space (diagonal) in mm
Overall length in mm
Overall width in mm
Overall height in mm
Sewing light voltage
Bulb
Presser foot height in mm
Drop feed-dog mechanism
Drop feed-dog via FHS
** possible with added FHS
Hook system
Needle system
Adjusting needle
Weight (excl. accessories)
activa 135
80W
DC/65W/24V
120–900/min
up & down
*
Yes
Yes
160 x 110 (192)
345
176
307
12V/5W
1 x 5W
7,5 mm
Yes
** Optional
BERNINA-CB
130/705H
130/705H TCN
ca. 9,6 kg
activa 145
80W
DC/65W/24V
120–900/min
up & down
*
Yes
Yes
160 x 110 (192)
345
176
307
12V/5W
1 x 5W
7,5 mm
Yes
** Optional
BERNINA-CB
130/705H
130/705H TCN
ca. 9,6 kg
Service Panel

5
The following tools and gauges are necessary:
TORX-Screwdriver (Commercially available):
Nr. 6, 8, 9, 10, 12, 15, 20, 25
Not available from BERNINA!
Tools
Circlip mounting tool Spring mounting tool
398 112.030
398 083.030
Rectifying tool
398 097.030
Torx Srewdriver
T10s
030 475.50.00
Eccentric Key
001 361.70.00
Rectifying tool
(Hook/Driver-Play)
001 357.70.00
Lower tension
001 358.70.00
Upper tension
398 080.040
Pinning tool
(Looplift)
030349.70.00
Pinning tool
(Stepping motor/Drive crank)
001 356.50.00
Pinning tool
(Stepping motor/Drive crank)
002 733.50.00
Hook race gauge
006 765.71.00
Buttonhole filter
008961.70.00
Presser foot height
6,0/8,5 mm
398 031 133
Torx-Screwdriver
TX8z
007 993.50.00
Feed-dog height
0,9/10 mm
398 024 030
Feeler gauge 0,3 mm
(Hook/Driver-Play)
398 022.030 (0,3 mm)
398 111.030 (0,15 mm)
Pinningtool
(Stepping motor stitch length)
030 652.50.00

6
The electronics of the BERNINA activa are basically
contained in two modules (printed circuits), namely on the
power L-print and the S-print (see block diagram).
Power supply L-print
The power L-print is mounted at the rear of the sewing
machine. The circuits produce the following direct current
voltages:
•5 V/DC for the logic on the S-print.
•12 V/DC for the sewing light.
•30 V/DC for the drive motor, bobbin winder motor and
stepping motors.
•16 V/DC for motor control on the S-print.
In case of malfunction, the fuse F-4A-T protects the parts
against overload. If a fuse blows, only an original replace-
ment with the correct ratings must be used.
S-print
The S-print is assembled with the latest SMD (Surface
Mounted Device) technology. SMD components allow a
very compact type of circuitry.
SMD prints cannot be repaired with conventional tools!
The micro-computer on the S-print receives an analogue
signal from the foot control which is converted into a digital
signal and given as a nominal value. When the foot control
is released (nominal value zero) the micro-computer
switches on the electric brake. The motor is stopped very
quickly in the required needle position.
When the sewing machine is switched on the stepping
motors are in any given position. There can also be any
given value in the memory of the micro-computer. So that
a defined basis is achieved, the stepping motors are
positioned by means of a signal from the micro-computer.
This position is then registered and set at zero in the
memory of the micro-computer. It is then possible to select
and sew any given stitch from this zero position.
The S-Print controls the functions of the stepping motors
to one another, calculates the signals of the sensors, com-
piles the results and displays them on the screen.
Integrated on the S-Print are the display, P-Print and
return button.
Description of the electronics

7Block Diagram
Display
Return-Button
Phototransistor and LED
Command circuit Power cirguit
Mains voltage
Foot control
Sewing light
Main motor
Bobbin winder
Stepping motor stitch width
Stepping motor stitch length
Buttonhole sensor
white
yellowwhitewhiteblackblueyellow

8 L-Print
Line Voltage!

9S-Print
Stitch width black 4-pole Spuler white 4-pole Sewing light yellow 2-pole Buttonhole sensor yellow 4-pole
Stitch length
blue
4-pole
Main motor
white
2-pole
L-Print
white
8-pole
Foot controler
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10 Diagnostic instructions
Warning Dangerous voltage levels !
Mains voltage (refer to L-print page 8).
The switch part of the L-print and mains cable carry
dangerous voltages.
For your own safety do not touch the L-print until about
30 seconds after the main voltage has been switched off.
This is the time required for the capacitors to discharge.
Important:
Follow safetly instructions on page 1!
Protection of electrical components against electrostatic discharges
If two insulation materials (e.g. shoe sole and floor) rub
together there can be a build-up of static electricity. Should
this be discharged through electronic components these
can be seriously damaged.
One of the most effective measures to conduct these char-
ges away is earthing.
1. A bench suitable for working with components in
today’s electronic industry has a surface that does not
allow the build-up of static electricity.
On the one hand the surface should be conductive so
that charges are conducted away but on the other hand
it should have enough resistance to prevent short-
circuiting and earthing of parts laid out on the bench.
2. By wearing a wristband that is connected to the bench
surface, static electricity can be conducted away from
the person. For safety reasons a resistance of approx.
1 M ohm has to be connected in series with the con-
ductive wristband.
3. Electronic parts may only be dispatched in their original
packaging.
Powering of the stepping motors
For the correct functioning of the stepping motors, it is
essential that they are brought into their «zero» position,
which is carried out after each new start of the machine, or
each change of functions. In order to adjust, or inspect this
«zero» position, the stepping motors must be in a powered
state (under current). Exchange motors can be adjusted
before they are fitted into the machine. They must be
connected to their relative connecting points on the S-
Before service or repair work is carried out
Print, which in turn must be connected to the power supply.
After connecting the machine to the mains supply, switch
the machine on and at the same time keep the Clr-button
pressed. Select now the service programme number 8. In
this programme the motors are powered with their correct
current values. The motors can now be adjusted according
to the service instructions given in the service manual.
Before service, or repair work is carried out, in particular
when an S-Print is exchanged the following machine data
must be secured:
•Specific machine data:
Configuration Test Config. page 11
Electronical balance Test No. 2 page 13
Buttonhole sensor Test Buttonhole page 14
Warning!
The sewing machine may only be connected to the mains
supply when the L-Print cover is mounted.
Work may only be carried out on the L-print and mains
cable when the mains plug has been withdrawn from the
mains supply.
Version Test No. 4 page 15
Hours sewn Test No. 5 page 15
Speed comp. factor Test No. 11 page 18

11Test Programme activa 125/135/145
Starting the test programme
•Attention! Turn the machine off.
•Place the service-panel on the machine.
•When switching the machine on, press at the same time
the «start» button.
•The sewing machine moves the stepping motors in the
basic position (short acustical nois) and is now in test
programme «SP» (Service Programme).
The machine is now in the initial servicing state and any
one of the 1–13 individual test programmes can be selec-
ted.
Test in basic servicing state
The following sensor signals can be checked in the initial state.
Configuaration of the machine
What is to be tested
Configurating the machine type
What to adjust
Initial state of service programme.
To modify the number, press simul-
taneously the «config» button and/or
the button «config+» or «config–».
Normal condition
The machine type can now be seen
in the display.
activa 125 = 1
activa 135 = 2
activa 145 = 3
activa Patchwork Edition (PE) = 4
By pressing the «clear» button (clr) the machine can at any
given time be brought into the initial sate.
Termination of the test programme
•Switch machine off.
•Switch machine on in the normal manner.
•The sewing machine can now be operated normally.
Function control of the foot control unit
What is to be tested
Foot control unit
What to adjust
Initial state of service operation.
Press foot control.
Normal condition
The function of the foot control is
indicated in the stitch length beam.
Configuration state
Stitch length bar

12 Test in basic servicing state contd.
Test for the P-Print
What is to be tested
P-Print
What to adjust
Initial state of service programme.
a)By turning the handwheel, bring
the needle in its lowest position.
b)Turn the handwheel slowly for-
wards and at the same time com-
pare the table in the next column.
Normal condition
In the L.C.R. needle position display
three digital signals can be read off.
L.C.R. = Left Centre Right
123
a) •
b)
c) •
d) • •
e)•••
f) • •
g) •
h) • •
a) •
Bobbin winder motor switch
What is to be tested
Winder motor switch
Control of motor
What to adjust
Initial state of service programme.
Switch on motor.
Press the foot control.
Normal condition
Field «bobbin switch» is active in the
L.M.R. display.
The speed of the bobbin winder
motor must be able to be regulated.
L.C.R. Display
Synchronisatio
L.C.R. Display
Bobbin winder

13Test Programmes
Test LCD Liquid Crystal Display (Service Panel)
What is to be tested
LCD (Liquid Crystal Display)
What to adjust
Select service programme LCD.
Normal condition
All details show up on the screen and
the LCD segment scrolls through all
possibilities.
Attention! Test 13 has a duration of ca 1
min. After which the test will be repea-
ted. The test can be interrupted at any
given time by pressing the «clr»-button.
Test No. 1 Sewing-off (Service Panel)
What is to be tested
Sewing-off:
Stitch length, width and L.C.R.
What to adjust
Select service programme no. 1.
Normal condition
The machine can now be sewn off.
L.M.R., Straight stitch, Stitch length
and width can be adjusted.
Test No. 2 Forward/reverse feed equalisation (Service Panel)
Electronical fine adjustment
What is to be tested
Forward and reverse feed equalisati-
on
What to adjust
Press BLC+ and BLC– button
simultaneously, this will bring you into
programm No. 2.
– BALANCE +
0 <3 3 >3 6
0 = reverse feed longest
3 = neutral position
6 = reverse feed shortest
Normal condition
In this programme the stitch pattern
No. 9 is active.
While sewing the forward and rever-
se feed can be adjusted with the +
and – buttons.
The stitch pattern No. 9 must be
closed.
The neutral position is the value 3.
The adjusted value is shown on the
screen and saved by pressing the
clear (clr) button.
blinks

14 Test Programmes
If the stitch formation is not absolutely closed after
electronic compensation, a fine adjustment can be made
with the balance regulating shaft 3.
Procedure:
•Remove the balance knob 1.
•Loosen screw 2.
•Turn the balance regulating shaft 3 as required.
•The balance knob (marker pin) can now be brought into
the basic position 4.
•Tighten the screw 2.
•Replace the balance button.
Mechanical fine adjustment
Turning in a clockwise direction
Turning in an anticlockwise direc-
4
1
2
3
Function of the automatic buttonholing device
What is to be tested
Automatic buttonhole compensation
What to adjust
Initial state of service programme.
Feed-dog at its highest point.
Mount the buttonhole foot.
Secure the buttonhole filter
No. 008 961.70.00 to the presser foot
bar. Lower presser foot and simulta-
neously press both buttonhole but-
tons.
Normal condition
The feed-dog will move to and fro,
until the compensation has been
achieved.
If no compensation is possible, then
the programme will terminate the test
after ca. 3 seconds.

15Test Programmes
Test No. 3 Automatic darning programme (Service Panel)
What is to be tested
Automatic darning programme
(Secondary test to buttonhole com-
pensation)
What to adjust
Select service programme No. 3.
Normal condition
The darning pattern must run parallel
on both ends. Sketch!!
Test No. 4 Software version (Service Panel)
What is to be tested
Software version
What to adjust
Select service programme No. 4.
Normal condition
The software version appears as
a number on the screen, e.g.
VO = Version 0
Test No. 5 Amount of sewing hours (Service Panel)
What is to be tested
Amount of sewing hours
(running time of motor)
What to adjust
Select service programme No. 5.
Normal condition
The number of hours appears as
a number on the screen.
5 =ˆ 60 min
3 =ˆ 36 min
1 =ˆ 12 min
100h (1–9)
101h (10–90)
102 h (100–900)
3x
x

16 Test Programmes
Test No. 6 Maximum speed equalisation (Service Panel)
What is to be tested
Maximum speed equalisation
(s.p.m. = stitch/minute)
The speed is set automatically
What to adjust
Select service programme No. 6.
Normal condition
Press foot control until «ok» appears
on the screen.The maximum speed
appears on the screen. Used for
example after disassembly /assembly
operation to compensate the
machine’s software.
If an F (Fault) appears then there is
something jamming.
In test No. 11 the speed compensati-
on factor can be read-off.The smoo-
thness of running for all shafts must
be
Test No. 7 Stepping motor stitch width (Service Panel)
What is to be tested
Step motor and S-print
What to adjust
Select service programme No. 7.
Normal condition
The step motor rotates back and
forth, the needle bar must move to
If the step motor does not rotate
then the fault can lie either with the
step motor or S-print. The faulty
components can be identified by
swapping the connections of the step
motors.
100s.p.m. (1–9)
101s.p.m. (10–90)
102s.p.m. (100–900)
Stitch width bar blinks
Warning: Disconnect
from the electricity
supply!

17Test Programmes
Test No. 8 Pinning position of stepping motors (Service Panel)
What is to be tested
Pinning position of step motors
What to adjust
Select service programme No. 8.
Normal condition
The step motors are activated to the
step position for pinning. «P»
appears on the screen.
Note:
Only used when the motors are external.
Test No. 9 Stepping motor stitch length (Service Panel)
What is to be tested
Step motors
What to adjust
Select service programme No. 9.
Normal condition
The step motor rotates back and
forth, the feed-dog must move to and
If the step motor does not rotate
then the fault can lie either with the
step motor or S-print. The faulty
components can be identified by
swapping the connections of the step
motors.
Stitch length bar
blinks
Warning: Disconnect
from the electricity
supply!

18 Test Programmes
Test No.10 Speed of the machine (Service Panel)
What is to be tested
Actual speed of the machine
What to adjust
Select programme No. 10.
Normal condition
Press foot control.
The speed is shown on the screen as
a number x 10 (e.g. 233 = 233
Test No.11 Displaying the speed compensation factor (Service Panel)
What is to be tested
Speed compensation factor
(Factor between 0–255)
What to adjust
Select programme No. 11.
Normal condition
The speed compensation factor is
used for declaring the mechanical
characteristics of the machine. The
higher the number, the more heavy
the machine is running. The higher
the value, the more the machine is
running sluggish and vice-versa. The
factor is normally between 160–200.
100s.p.m. (1–9)
101s.p.m. (10–90)
102s.p.m. (100–900)
100(1–9)
101(10–90)
102(100–900)

19Test Programmes
Test No.12 Start/Stop function (Service Panel)
Factory use only
What is to be tested
Permanent test of the machine
What to adjust
Select service programme No. 12.
Normal condition
Press the foot control.
The machine will start and stop at
a 7 second interval.
Test No.13 Stepping motors and S-print (Service Panel)
What is to be tested
Stepping motors and S-print
What to adjust
Select service programme No. 13.
Normal condition
The stepping motors rotate back and
forth, the feed-dog and needle bar
must move to and fro.
If the stepping motors do not rotate
then the fault can lie either with the
stepping motors or S-print. The faulty
components can be identified by
swapping the connections of the
stepping motors.
Stitch length bar
blinks
Stitch width bar blinks
Warning: Disconnect
from the electricity
supply!