Bang Olufsen Beolab 4 Service Manual

BeoLab 4

Type 6650, 6652

Service Manual
English

German, French, Italian, Spanish, Danish, Dutch and Japanese versions
are available in the Retail System

This Service Manual must be returned with the
defective parts/back-up suitcase !

CONTENTS

Survey of modules ...................................................................... 1.1

How to service ......................................................................... 1.2

Warnings – Insulating test ........................................................ 2.1

Adjustments ............................................................................ 3.1

Repair tips ................................................................................ 4.1

Disassembly ............................................................................. 5.1

Specification guidelines for service use .....................................

6.1

Block diagram ........................................................................... 7.1

Wiring diagram ........................................................................ 7.2

Available parts ......................................................................... 8.1

1.1Survey of modules

PCB1 Amplifier

PCB2 SMPS

PCB3 Filter

PCB4 LED

PCB5 Switch

PCB6 Input

Survey of modules

4

5
6

1
2

3

How to service

1.2

How to service

Front line service

BeoLab 4 is to be serviced in the customer’s home when it comes to electrical
symptoms or exchange of mechanical parts. In this way you avoid having to make
more than one visit and using minimum of time on the case, all for the benefit of
the customer.
BeoLab 4 has been split-up into as few service items as possible. Each service friendly
item is packed individually, prepared for worldwide transport, and has a separate
seven digit spare part number to be found in the Bang & Olufsen Retail System or
the Service Manual. The exploded view drawing will show the service spare parts.

Back-up suitcase

A back-up suitcase contains all necessary electrical modules for front-line repair of
one loudspeaker. Cabinet parts must be ordered separately in the Retail System or
directly from B&O Struer DK.
The replaced modules must be returned for repair at Bang & Olufsen, Module
Repair Department. Use the Module Repair form or the form in the Retail Order
System, Exchange Module.

Delivery

As there is only one type number for BeoLab 4, the product can be used for all
markets with 100 to 240 Vac mains voltage. When you order BeoLab 4 (set of
two) this includes two mains cables, two Power Link cables and two boxes with
the three front covers in the chosen colour. This means that the delivery will
consist of four boxes.
This setup allows our packaging department to pack the specific order for the
customer no matter which country it goes to or the colour chosen.

Installation and setting-up

Only the switch for loudspeaker placement and the switch for Left or Right - Line
or PC must be set into correct position as described in the User Guide before
Power Link/Line signal and AC power wires are connected. If the Power Link is
used, the switch is for Left or Right setting. If Line connection is used (via mini-jack
plug) the switch is for Line (0 to 1V) or PC-line (0 to 2V) setting. See more details
in the User Guide. The automatic switch-off circuit is only active with the switch in
Line position, and is not active with the switch in PC-line position.
The LED will indicate on (green) or off (red) only.

Fault Finding

Before troubleshooting is initiated, let the customer demonstrate the fault, if possible.
There are four electrical modules in the product, and furthermore two additional
modules. One with a LED and one with a mini jack socket. Therefore a faulty module
is easy to point out in most cases. The PCB’s has been divided into the functionality:
Inputs, Amplifier, Power supply and Filter.
No special service programs are available in this product or via the ServiceTool.
If there is a fault in the SMPS (PCB2) or Amplifier (PCB1) the LED is typically off.
Only the tweeter unit is protected by a circuit that measures the resistance in the coil,
and will automatically turn down the signal level for the tweeter shortly if it is too
high for a period.

How to service 1.3

Replacement

Replacement of a loudspeaker unit or the amplifier.
Each loudspeaker is individually adjusted from production to secure optimal stereo
perspective.
If a defective loudspeaker unit must be replaced, it is easily done without adjustment
due to the specifications of the unit.

Mechanics

All cabinet parts as e.g. the socket panel can be changed on-site. All surfaces can
be cleaned with a mild detergent.
Internal parts are supplied as service kits, e.g. the loudspeakers, PCB’s etc.
A product cover (soft) for service, black, can be ordered for transport of BeoLab 4.

2.1 Warnings – Insulating test

Warnings

ESD

When electrical replacements or disassembly is taking place, use an ESD-mat. The
internal electronics are very sensitive to static electricity.

Handling

Wear cotton gloves to avoid any fingerprints on the product.

The surfaces on the product are very sensitive, so handling should be done with
great care to avoid damage.

Cleaning of the speaker surfaces should only be done with a lint-free cloth which
you have dipped in lukewarm water and wrung firmly.

Insulation test

The product must be insulation tested after having been dismantled. Make the test
when the set has been reassembled and is ready to be returned to the customer.
Flashover must not occur during the test.

Make the insulation test as follows:
Short-circuit the two pins of the mains plug and connect them to one of the
terminals of the insulation tester.
Connect the other terminal to ground on the Power Link socket.

NOTE!
To avoid damaging the product it is essential that both terminals of the insulation
tester have good contact.

During the test the current must not exceed 5 mA.
Slowly increase the voltage on the insulation tester until a voltage of 2.5 kV (ac) is
obtained. Maintain the voltage level for one second, then slowly decrease the
voltage to 0 V (ac).

STATIC ELECTRICITY
MAY DESTROY THE
PRODUCT

Adjustments 3.1

Adjustments

Adjustments after replacing PCB3 or PCB5

Read out the adjustment position of the old potentiometers, VR601 & VR701, and
set the new potentiometers to the same position.

PCB3 – VR601

PCB5 – VR701

VR601

VR701

4.1 Repair tips

Repair tips

Hum in loudspeaker when no music is played.
The Power Link cable must be of type MK III or higher.
The ground connection in Power Link cable lower than MK III may be insufficient
for optimum sound performance.
The loudspeaker units can be checked by an ohm-meter (tweeter 5.7Ω ±10%;
woofer 6.7Ω ±10%).

Power Link

MK III

Disassembly 5.1

- Pull off front covers

Remove front cover

5.2 Remove woofer

4x

TX20

- Remove screws

- Remove cables

Cables

- Pull off front cover

- Remove cables

ESD

PCB xx

ESD-Mat

Do not pull - release lock!

Remove tweeter 5.3

2x

TX20

- Remove screws

- Remove cables
Do not pull - release lock!

Cables

- Pull off front cover

- Remove cables

ESD

PCB xx

ESD-Mat

5.4 Replace cabinet

6x

TX20

- Remove plug

- Remove screws

☞ 5.1 Remove front cover

☞ 5.2 Remove woofer

☞ 5.3 Remove tweeter

- Pull off cabinet

- Remove plug

1P301

3P612

ESD

PCB xx

ESD-Mat

- Remember to transfer label to new cabinet!

Note that this may require some effort

Replace port 5.5

- Remove screws

- Lift off port as shown

2x

☞ 5.4 Remove cabinet

5.6 Replace PCB1, Amplifier

- Gently pull off bracket with PCB1 mounted

2x

- Remove screws

☞ 5.4 Remove cabinet

☞ 5.5 Remove port

- Remove screws and pull off PCB1

4x

ESD

PCB xx

ESD-Mat

Replace PCB2, SMPS 5.7

- Remove screws

- Remove plugs

☞ 5.4 Remove cabinet

- Pull off PCB2

6x

2P1

2P2

ESD

PCB xx

ESD-Mat

5.8 Replace PCB3, Filter

- Remove screws

- Remove plugs

☞ 5.4 Remove cabinet

- Gently pull off PCB1 and PCB3

6x

- Pull off PCB1

3P606

2P2

3P610

ESD

PCB xx

ESD-Mat

Replace PCB5, Switch 5.9

- Remove screws

☞ 5.4 Remove cabinet

☞ 5.5 Remove port

☞ 5.8 Remove PCB3, Filter

- Pull off as shown
(Be aware of the cables!)

- Remove plugs

4x

5P602

5P603

- Remove screws

4x

ESD

PCB xx

ESD-Mat

5.10 Replace PCB6, Input

- Remove screw

☞ 5.4 Remove cabinet

☞ 5.5 Remove port

☞ 5.8 Remove PCB3, Filter

- Remove bracket

1x

☞ 5.9 Remove PCB5, Switch

1x

ESD

PCB xx

ESD-Mat

Replace bottom plate 5.11

- Remember to transfer label

☞ 5.4 Remove cabinet

☞ 5.5 Remove port

☞ 5.7 Remove PCB2, SMPS

☞ 5.9 Remove PCB5, Switch

☞ 5.8 Remove PCB3, Filter

☞ 5.10 Remove PCB6, Input

5.12

Specification guidelines for service use

Specification guidelines for service use BeoLab 4

Type 6650, 6652
Dimensions W x H x D 19.7 x 20.5 x 21.5 cm
Weight 1.7 kg
Cabinet finish Black, red, blue, dark grey
Power consumption Typical: 7 W, Stand-by: 0.5 W
Voltage 100-240 V
Power amplifier, bass 35 W, Class D, ICEpower®
Power amplifier, treble 35 W, Class D, ICEpower®
Effective Frequency range 50 – 20,000 Hz
Crossover frequency 3.3 kHz
Cabinet principle Bass reflex
Net volume, bass 1.55 litres
Magnetically shielded No
Woofer 101.6 mm (4”), concave diaphragm 6.7W ±10%
Tweeter 19 mm (¾”), fabric dome 5.7W ±10%
Bass equalization ABL (Adaptive Bass Linearization)
Input sensitivity (Power Link) 125 mV (88 dB SPL)
Input sensitivity (line) 125 mV (88 dB SPL) - Auto switch on
Switch off time (line) 3 min.
Indicator LED for on (green) or off (red)
Operation Free, Wall or Corner position
Left, Right or LINE, PC switch
Protection Thermal protection of tweeter and SMPS

6.1

Power Link 1 (use semi-balanced PL cable type MK III, or fully mounted PL cable)
Mini-jack (line-in) Via mini-jack plug 0-1 V (Line - automatic on/off) or 0-2 V
(PC - always on) selected by switch

Accessories
Ceiling bracket, type 2177 1217711 (a pair)
Floor stand, type 2178 1217811 (a pair)
Wall bracket, type 2179 1217911 (a pair)

Cable mini-jack stereo to 2 x mini-jack mono (L and R), 2.5 m 6270250 black
Cable RCA/mini-jack mono, 5 m, black 6270273 (a pair)
Power Link splitter (one male to two female PL plugs) 6270706

Subject to change without notice

7.1 Block diagram

Block diagram

VR701

VR601

7.2

Wiring diagram

Wiring diagram

8.1 Available parts

Available parts
BeoLab 4

9001

9002

9003

9004

9001

9006

9008

9007

9001

9009

9010

9011

9012

9013

9014

1

3

4

5

2

6

Incl. pos. no. 9006

9005

1

1

1

1

1

1

2

2

4

4

3

5

3

3

3

5

5

5

3

3

3

3

3

3

3

3

3

3

7

6

2

Available parts 8.2

BeoLab 4

9001 1604244 Front cover, red
1604246 Front cover, black
1604248 Front cover, blue
1604249 Front cover, dark grey
9002 3430049 Cabinet
9003 8480048 Tweeter
9004 8480049 Woofer
9005 6100273 Mains cable, EU
6100329 Mains cable, UK
6100307 Mains cable, US
6100332 Mains cable, AUS
6100386 Mains cable, KOR
6100331 Mains cable, JP
6100047 Mains cable, CHN
9006 3340293 Gasket
9007 3454102 Bottom incl. pos. no. 9006
9008 3390066 Bag w/parts
9009 3358148 Heat zink
9010 3340291 Gasket
9011 3131096 Housing
9012 3340290 Gasket
9013 3458134 Port
9014 3340292 Gasket

1Module 8002619 PCB1, Amplifier

2Module 8002620 PCB2, SMPS

3Module 8002621 PCB3, Filter

4Module 8002622 PCB4, LED

5Module 8002623 PCB5, Switch

6Module 8002624 PCB6, Input

Survey of screws etc.

1 2011006 Screw 4 x 10mm
2 2011008 Screw 4 x 10mm
3 2011009 Screw 3 x 8mm
4 2011013 Screw 2.6 x 8mm
5 2011012 Screw 2.6 x 8mm
6 2011011 Screw 3 x 6mm
7 2011010 Screw 3 x 6mm

Wire bundle

6277995 Wire f/speakers

Parts not shown

3395297 Back-up suitcase
3375491 Product cover
6270250 Cable mini-jack stereo
6270273 Cable RCA/mini jack
3375590 Autosol chrom polishing

Packing

3392894 Packing, complete

Available documentation

See Retail Ordering System

8.3 Available parts

Floor Stand 2178

1217811

9101

9102

9103

9104

1

2

2

2

2

Incl. pos. nos. 9102, 1

9101 3932011 Tube incl. pos. nos. 9102, 1
9102 2369004 Cable clip
9103 3162238 Cover plate
9104 3103392 Rubber foot

1 2046017 Screw 6 x 16mm
2 3390078 Bag w/parts

3390082 Cable manager

3507402 Guide f/2178
3507662 Guide f/cable manager

Available parts 8.4

Packing – Floor Stand

9301

9301

9302

9303

9301 3396330 Foam packing, set
9302 3016012 Guide f/cover plate
9303 3392486 Outer carton

8.5 Available parts

Ceiling bracket 2177

1217711

3507401 Guide

Wall bracket 2179

1217911

3507403 Guide

Bang & Olufsen
DK-7600 Struer
Denmark

Phone [phone]*
Fax [phone]

3538032 12-06 A