Alcad TCB-440 Guia Del Usuario página 29

panel defined as the main one. Make sure that the multiple-access video
line is correctly loaded (resistence of 220 ohms in the unused terminals
T2+,T2-). If splitters have been used in the distribution, check that the
voltage between - and + of the splitters is 15 Vdc. Check that twisted pair
line has a 120 Ohm load: a) if tap-offs have been connected in series
the 120 Ohm resistance must be removed from all the intermediate tap-
offs; b) with monitors in series cut the 120 Ohm resistances on all the
connection brackets, but from the one at the end of the line. Check twisted
pair connection in splitters and tap-offs. If you cannot find the fault, there
may be something wrong with the video unit.
Poor image quality on one monitor: distorted picture, ghost images, loss
of synchronisation.
Check the polarity of the twisted pair.
Check that twisted pair line is charged with 120 Ohm: iwith monitors in
series cut the 120 Ohm resistances on all the connection brackets, but
from the one at the end of the line. Check the position of the J1 configuration
jumper in the connection brackets. If you cannot find the fault there may
be something wrong with the monitor.
Auto switch-on does not work on any monitor.
In multiple access installations, check that one entrance panel has been
defined as the main one and check connections D2 and D3 between
DIGITAL DOOR ENTRY SYSTEMS
Auto switch-on does not work on one monitor.
White picture in all the monitors
White picture in one monitor
.
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 that the twisted pair to the monitors is connected to the T1+ and
T1 terminals of the video unit. In multiple access installation, check the
T2+, T2 connections of the twisted pair between the different video units.
Check the connection between the video and the audio units. If splitters
have been used in the distribution, check that the voltage between - and
+ of the splitters is 15 Vdc. Check the connections of the twisted pair from
the video unit to the monitors. If failure is not detected, there may be
something wrong with the video unit, any tap-off or any splitter.
Check the connection between the connection bracket and the monitor.
Check the connections of the twisted pair in the monitor's connection
bracket. Check twisted pair'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.