need service manual schematic dygram kds vs-21

[Asim]

Hello friends
My name is Asim and i am an engineer most of my work related to taxtile machines but some time i have the job of monitor repairing therefore now a dayes i have a monitor brand name korian data system(KDS).The condition of the monitor is that when ever i connect to the pc it does not show any video its on properly but i cant found the video.First i checked the supply card found ok then i checked the main board and found some faulty parts like risistance trasister and ic i replace them but before the power on i wnna check all the other thing related the problum.The board has no blocks and no check that define which circuit is this there is no marking.So i need the service manual and schematic diagram . I will be very thak full to you if some body help me to solve my problum.
Thanks with best regards
Asim