Conventional Systems Technical Manual - Alcad

Video system does not work in one monitor: autoswitch-on, screen doesn´t come on when receiving acall,..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 themonitor. Check that the voltage between +, - of the connectionbracket is 14 ± 15% Vdc. If failure cannot be found, there maybe something wrong with the monitor.Poor image quality on all the monitors: distortedpicture, ghost images, loss of synchronisation.Check that you have only one entrance panel defined as themain one. Check that the voltage of the video units between +,- is 15 ± 10% Vdc. If splitters have been used in the distribution,check that the voltage between +, - of the splitters is 14± 15% Vdc. Check that coaxial cable line has a 75 Ohm load:a) if tap-offs have been connected in series the 75 Ohm resistancemust be removed from all the intermediate tap-offs; b)with monitors in series cut the 75 Ohm resistances on all theconnection brackets, but from the one at the end of the line; c)Check that resistences of 75 ohms are connected in the unusedterminals V2, M. Check coaxial connection in splitters and tapoffs.If you cannot find the fault, there may be something wrongwith the video unit.Poor image quality on one monitor: distorted picture,ghost images, loss of synchronisation.Check that coaxial cable line is charged with 75 Ohm: withmonitors in series cut the 75 Ohm resistances on all the connectionbrackets, but from the one at the end of the line. If youcannot find the fault there may be something wrong with themonitor.Auto switch-on does not work on any monitor.Check that you have only one entrance panel defined as themain one. Make certain that connectors 17,18 on the entrancepanels are connected up. Check that the voltage between1,2 of the audio unit, without pushing the auto switch-on buttonis 5 ± 10% Vdc. If you cannot find the fault there may be somethingwrong with the audio unit.Auto switch-on does not work on one monitor.Check that pushing the auto switch-on button the red ledflash. Check that the system is not engaged. If you cannot findthe fault, there may be something wrong with the connectionbracket or the monitor.Blank screen on all the monitors.Check the connection between the video unit and the audiounit. Check that the coaxial cable to the monitors is connectedto the V1 and M terminals of the video unit. If splitters havebeen used in the distribution, check that the voltage between +,- of the splitters is 14 ± 15% Vdc. If failure is not detected,there may be something wrong with the audio unit, video unitor any splitter.Blank screen on all the monitors of a flat.Check the position of the J1 configuration jumper in the connectionbracket. Check coaxial's connection from the connectionbracket to the video unit. If splitters have been used in thedistribution, check that the voltage between +, - of the splittersis 14 Vdc ± 15%. If the fault cannot be found, there may besomething wrong with the tap-off of that floor or the splitter ofthe flat.Blank screen on one of the monitors of a house orflat.Check the connection between the connection bracket andthe monitor. Check the connections of the coaxial cable in themonitor's connection bracket. If splitters have been used in thedistribution, check the position of the J1 configuration jumperin the connection bracket. Check coaxial's connection from theconnection bracket to the video unit. If failure is not detectedthere may be something wrong with the tap-off, connectionbracket or monitor.303