OK, did some investigations and would like to inform all of the outcomes.
1/ Screen blown, got another screen - works good
2/ 5m HDMI lead replaced but old one seems OK
3/ Looks as if 2 HDMI tails with boosters in back of wall plates are damaged - appears to be the cause of screen on and off
4/...
Hello all. had a thunderstorm yesterday, took out our security system. Monitor kaputt but NVR still sort of works.
New monitor and the cameras (3 x hard wired - not over wifi) show no picture and the monitor screen has images of "no link" flashing on and off at varying intervals of .5 sec to 5...