Monitor flickers and dims when a bright image is shown

VPN
1

I got an imac monitor from my friend about 2 years ago. I bought a driver board from ebay and it has worked perfectly up until yesterday and today.

If it shows a dim image, then it will show it at normal brightness and not flicker.

dim image shown to the monitor and the brightness is what it should be

Now, if i put a bright image on the screen, then it starts to dim and flicker very badly.

bright image shown and flickering is occuring.

I did some debugging, and if i have the window of bright small, then it shows full brightness with no issues, but when i start making it bigger, it starts to flicker fast then as it gets even bigger, the flickering slows down and becomes a huge issue.

Ill admit that the setup isnt the best, it looked better before this happened, but i checked all the connectors and wires and the power supply and all the electronics and they look perfectly fine with no heat discoloration or broken components. There is also no burnt smell.

what im using…

I have researched and can not find anything that is this niche. If im in the wrong sub, please let me know where i should move to.

I am thinking its the power supply. I used the stock power supply that the board came with and have had no problems until now.

2

UPDATE!!!

My suspicions of it being the power supply were correct. It was messed up. I used a power supply that i had laying around with the same specs and i have no more issues!!!

Im glad i dont have to waste money on a new monitor.

3

Apologies, haven’t read your whole post. But weird unexplainable behavior is usually always the power supply acting up.

4

it was the power supply.