MAINTENANCE OF THE BVR20
If a fault is suspected on any of the BVR20 modules, simple substitution with a spare can be carried out as first-
line maintenance. Before removing any module ensure that the two DC supplies are disconnected by removing
the lower 8-way blue plug from the CPU module. The CPU module BVRCPU – as viewed from the rear – is
located at the extreme right hand side, position 21.
Carefully remove all connectors to the suspected module with a small posi-drive screwdriver, release the two
retaining screws at the rear of the module and, observing electro-static precautions, carefully remove the
module. To replace the module, carefully slide in the new module, fasten it using the two screws, replace the
connectors and now you are ready to apply power. Please ensure that the correct module has been fitted in the
correct position.
The heart of the BVR20 is the CPU module – BVRCPU - which controls all the input and output routeing,
together with all monitoring facilities. Please note this module must only be fitted in position 21, at the extreme
right hand side of the BVR20.
As a simple guide to fault finding, should one zone output be faulty then it would be true to suspect the output
card serving that zone – especially if the other channel is operating.
Input modules – BVRI4 - have four inputs, each with a maximum sensitivity of -20dBm (approximately
80mV), which is amplified and presented to the audio bus structure at 0 dBm (approximately 800mV).
The message module –BVR802 – has the facility for four messages and provides 20 opto isolated inputs to
interface with fire detection panel sounder circuits. Again the signal from each message is presented to the
audio bus at 0dBm. The system monitors the audio output presented to the first output module and the DC bias
present at the output of the digital-to-analogue converter, which is displayed as a memory fault.
The dual output card –BVR02 – has two line outputs of 0dBm and provides frequency equalisation and gating
from all the 20 input signals. This module also provides volt-free relay contacts, which change condition when
the zone is busy.
On the system there are two signal input/output cards – the BVRIO40 which, in conjunction with the interface
cards – the BVRACO, monitor the external loudspeaker lines using the BEL1 end of line unit. The BVRACO
also provides automatic changeover in the event of a faulty amplifier to a reserve. The module positioned in
P18 serves all the ‘A’ circuits, whilst the one fitted to P19 serves all the ‘B’ circuits. Input signals for the
reserve amplifiers are obtained from output modules plugged into P16 and P17 and automatically, in the event
of an amplifier failure, route the correct source of signals to the relevant reserve amplifier.
All of the BVR20 modules are fed from a dual supply line unregulated and regulation is provided on each
module. The supply input to each card is protected by a poly-switch self-resetable fuse and, in the case of the
CPU, a dual regulator path is provided.
Please note: Under no circumstances remove or replace a module with the power supply connected.
Should a faulty module be discovered, repair can only be accomplished in an equipped workshop. Therefore,
we recommend that first-line maintenance is only by replacing modules from a spares stock.
Low VoltageDirective
73/23/EEC asam ended
by93/68/EEC
EM C Directive
89/336/EEC asam ended
by92/31/EEC and93/68/EEC
Applies only when the item s
arecorrectlyfittedandoperated
in or with products of our
m anufacture and are installed
in arecom m endedenclosure.
