Bang & Olufsen BeoCenter 2 MK II, Service Manual

Page: 23 / 68

Service tips
Doing fault searching and measurements, there is some special features you should
be aware of.
1. In order to power up, the Master Unit and Socket Unit needs to be connected
thrugh the interface cable, due to the fact that the main SMPS is placed in the
Socket Unit, along with the RGB Video processor and microprocessor.
2. Right before signals from the Master Unit and Socket Unit goes into the interface
cable, they are converted into current signals. If you need to measure the signals
going in and out the interface cable, you need to measure before or after the
converters.
3. All SMPS´s in the Master Unit is synchronized along with the SMPS´s in the Socket
Unit. But the main SMPS in the Socket Unit is only synchronized, along with the
rest, when the BeoCenter 2 is receiving AM signal in RADIO mode. If the synchronizing
isn’t working, it can create a lot of noise in the AM reception.
4. The DVD/CD are not able to start up when the keyboards are open or dismantled,
due to exposure of the laser pickup. A little magnet should be used to activate the
hall sensor. Disconnect the BeoCenter 2 from the mains, place the magnet and
then connect the BeoCenter 2 to the mains again. After start up, the magnet can
be removed, and the hall sensor will still detect the keyboards as closed, which
give full functionality with the keyboards open/detached, until load is pressed.
See page 5.19.
5. If measurements need to be done on the outlet plugs on the Socket Panel, remember
to use the GND in the same plug you are about to measure in. The GND level can
vary from plug to plug.
6. All data communication to the DVD interface is done with signal levels on 3.3 volts,
if this level vary, it can cause data failure.
7. The VFD display has an auto contrast function, if this fail, the light in the display
can vary from very bright to almost black.
8. The interface cable between the Master Unit and the Socket Unit is very sensitive
to sharp bends or any other large mechanical influence. Damage can result in poor
sound/picture quality or fault in the data communication between the Master Unit
and Socket Unit.
9. If one of the two IR-modules fails, the IR sensitivity will be reduced.
10. All analogue audio processing is done in the analogue Audio engine (PCB50). The
digital S/PDIF signal is not going through any processing, beside it is DC levelled on
AV panel DAB (PCB).
Service tips 4.1