Ok, just for you to know. I solved the problem by zapping the PRAM (apple-alt-p-r)

Hi everybody,

I followed this guide, step by step to replace the former HDD by a brand new SDD.

Unfortunately, since my iMac is reassembled, I've been facing an issue with the display.

It shows like statics in from of the image. We see the desktop, icons and system in background but there are glittering red and grey points in front of it. i've tried to disassemble, check the different cables and plugs, but nothing... Could you help me, please ?