Alcad GRF-200 Mode D'emploi page 26

The sound produces feedback.
Adjust the feedback control of the audio unit (see step 1 on page
21). If the feedback persists, lower the volume using the volume
controls of the audio unit.
The electric lock doesn’t work.
With the jumper between terminal 10 and
voltage between 12 and 11 in the audio unit is 17 ±10% Vdc, by
making a bridge between terminals 22 and 11. If you cannot find
the fault, there may be something wrong with the electric lock.
In installations with multiple points of entry, calling on one of
the entrance panels does not deactivate the other panels of
the system.
Check connections D3 and D2 between the different panels of the
system. If you cannot find the fault, there may be something wrong
with the audio unit.
In housing compound installations, making a call from one of
the external entrance panels does not disable the entrance
panels of the building which is being called.
Check connections D3 and D2 from the entrance panel to the
identifying accessories of the building. If the fault cannot be found,
there may be something wrong with the audio unit or the identifying
accessory.
The video system does not work in any monitor: auto switch-
on, screen doesn´t come on when receiving a call,..
If this is the case, check the mains voltage in the power supply
unit feeding the monitors and the cameras. Check that the voltage
of the power supply between + and – is 17 ±10% Vdc. Check if
there's a short circuit and rectify it. Disconnect the power supplies
supply for 1 minute and reconnect it. If the breakdown continues,
disconnect all the + and – terminals from the power supply unit
and check that voltage between + and – is 21 ± 10% Vdc. If it's
not correct, there may be something wrong with the power supply.
Video system does not work in one monitor: auto switch-on,
screen doesn´t come on when receiving a call,..
Check that the ON/OFF switch for the video is in ON position
(on the left). Check that the red led of the monitor is on. Check the
connection between the connection bracket and the monitor. Check
that the voltage between + and – of the connection bracket is 17
± 10% Vdc. If failure cannot be found, there may be something
wrong with the monitor.
Poor image quality on all the monitors: distorted picture, ghost
images, loss of synchronisation.
In several access installation, check that you have only one entrance
panel defined as the main one. If splitters have been used in the
distribution, check that the voltage between + and – of the splitters
is 17 ± 10% Vdc. Check that coaxial cable line has a 75 Ohm
load: a) if tap-offs have been connected in series the 75 Ohm
D I G I TA L V I D E O D O O R E N T R Y S Y S T E M S
, check that the
Poor image quality on one monitor: distorted picture, ghost
images, loss of synchronisation.
Auto switch-on does not work on any monitor.
Auto switch-on does not work on one monitor.
Blank screen on all the monitors.
Blank screen on all the monitors of a dwelling.
Blank screen on one of the monitors of a house or dwelling.
resistance must be removed from all the intermediate tap-offs; b)
with monitors in series cut the 75 Ohm resistances on all the
connection brackets, but from the one at the end of the line; c)
Check coaxial connection in splitters and tap-offs. Check that
resistences of 75 ohms are connected in the unused terminals V2,
M. If you cannot find the fault, there may be something wrong
with the video unit.
Check that coaxial cable line is charged with 75 Ohm: with
monitors in series cut the 75 Ohm resistances on all the connection
brackets, but from the one at the end of the line. If you cannot
find the fault there may be something wrong with the monitor.
Check that one entrance panel has been defined as the main one
and check connections D3 and D2 between different entrance
panels. If you cannot find the fault there may be something wrong
with the audio unit.
Check that pushing the auto switch-on button the red led flash.
Check that the system is not engaged. If you cannot find the fault,
there may be something wrong with the connection bracket or the
monitor.
Check the connection between the video and the audio units. If
this is the case, check connections V2, M and V4, M of the video
units of the installation. If splitters have been used in the distribution,
check that the voltage between + and – of the splitters is 17 ±
10% Vdc. Check the connections of the coaxial cable from the
video unit to the monitors. If failure is not detected, there may be
something wrong with the audio unit, video unit or any splitter.
Check the position of the J1 configuration jumper in the connection
bracket. Check coaxial's connection from the connection bracket
to the video unit. If splitters have been used in the distribution,
check that the voltage between + and – of the splitters is 17 Vdc
± 10%. If the fault cannot be found, there may be something wrong
with the tap-off or the splitter of he dwelling.
Check the connection between the connection bracket and the
monitor. Check the connections of the coaxial cable in the monitor's
connection bracket. If splitters have been used in the distribution,
check the position of the J1 configuration jumper in the connection
bracket. Check coaxial's connection from the connection bracket
to the video unit. If failure is not detected there may be something
wrong with the tap-off, connection bracket or monitor.