Bang & Olufsen BeoLab 4, Service Manual

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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.