Bart this "so I’ve removed that “strip” / daughter board from my working LCD - and to do so I had to cut those ribbons / flexes (which they are connected to LCD" needs to be further investigated. Post some good pictures with your '''''Question''''' so we can see what you see. Right now it appears as if your iMac doesn't recognize what you set out to do and henceforth gets throttled to bear minimum. You may just have to replace the LCD completely. [guide|21499]