Bang & Olufsen BEOLINK Handbook page 41

Service mode
MASTER LINK
Products with a display have a service mode where Master Link faults can be
read off. Note that the fault reading indicates that there is a system fault;
this is not the same as saying there is a fault with the actual product where
the fault message appears.
BeoLab 3500 and BeoVision Avant are examples of products with service
mode. See service instructions for the individual product to find out how
you can access service mode and the possibilities provided by service mode.
The example of service mode below is from BeoLab 3500.
ERROR 1: - Address configuration is impossible.
Fault with address configuration. No address was found, because there are
too many units connected to the Master Link.
- Remove all products from the Master Link connection and reconnect
them one by one other until the fault appears. Disconnect the product
again.
ERROR 2: - Master Link data pulled low.
It is not possible to transmit on the Master Link because it is pulled low.
This fault can arise if there is no Master Link driver circuit, or as a result of a
physical short circuit in the Master Link or in the data receiver circuit.
- Remove the products from the Master Link connection one by one and
see if it starts again.
- Reset the faulty product and check the connection (cable/plug) and
signal path (data receiver circuit). See section on repair tips for a
description of the data receiver circuit.
ERROR 3: - Master Link data pulled high.
It is not possible to transmit on the Master Link because it has been pulled
high. This fault arises either because the pull-up resistance in the system
has become too small, or as a result of a fault in the data receiver circuit.
- Remove the products from the Master Link connection one by one and
see if it starts again.
- Reset the faulty product, check if the Master Link cable is too long, and
check the signal path (the data receiver circuit). See section on repair
tips for a description of the data receiver circuit.
ERROR 4: - Data collision on Master Link.
The data traffic on the Master Link has been unusually high, or a product is
blocked and cannot receive data telegrams.
- Repeat the operating sequence.
- Remove the products from the Master Link connection one by one in
order to find out which product is blocked. Reset the faulty product and
check the Master Link connection (cable/plug) and signal paths (the
amplifiers in the data receiver circuit).
See the service guide for individual products if you require further
information.
37