iMac 27 2011 - Screen flickering

[javier_herart]

Hello!

I replaced the GPU card on this Imac because of distorted video issue.
It came back 3 days after with another issue. The screen is flickering, the computer is still on, you can still hear the audio, no freeze, after some flickers it came back ok.

Any idea?

Thanks

 

[2informaticos]

Backlight flickers, or image too?
Check image on external monitor.

 

[javier_herart]

Only backlight, I can see the image with a flashlight

 

[2informaticos]

You should discard the LCD first.