tldr

• it was the display port cable , just swapped it and it worked.

switch tubelight flickered my monitor

It has been many months or should I say years that I could not figure out the root cause of this issue as to why my monitor flickers or momentarily shuts off and turns back on everytime someone switches on the tubelight (led/cfl etc.) in my room or on same power lines. this thing has been bothering me for such a long time and at times it did worry me that I dont damage my monitor if I kept neglecting it.

solution

So i decided to dig further into this and started by taking and swapping things one by one.

• the monitor power cable , no luck
• the pc cabinet power cable , no luck

I also happen to have a dual monitor setup and this occurred only on one monitor and not on the other so it also made me confident that there has to be a solution. with this I was also sure that this cant be a motherboard or gpu thing.

• then I also tried to swap the tubelight with different styles like led , cold cathode style etc but no luck this kept repeating.

• them I decided to swap the display port cable between my two monitors and much to my surprise that seemed to work.

so the problem is the display port cable and I just checked my spares and I did have a brand new display port cable , just swapped it with a new one and problem solved.

Hope this helps someone else. :)