How to diagnose the cause of video loss on the monitor/projector?

Question

Projectors

Good afternoon!
Can you please tell me the best way to diagnose the problem?
When connecting to the system unit of the monitor via DVI + two projectors via VGA via a splitter ( https://www.oldi.ru/catalog/element/0171556/) , the image on the monitor goes blank after a random time.
We changed the video card, cables, splitter model, monitor and projector settings, the problem persists.
At the same time, if you use a laptop instead of a monitor with a system unit and connect the same two projectors to it via VGA, the image does not disappear either on the laptop screen or on the projectors.
It remains to change the monitor and see if the problem persists. If it's the monitor, then what could be the specific reason?

Answer 1

It is obvious that the problem is in the monitor, everything else has been changed. Projectors, as I understand it, work without comment. Connect the monitor to the computer without a splitter and see if there is a problem. There can be many reasons for a monitor malfunction, for example, contact failures when heated, cold soldering, etc.