Hi, I got this iMac to fix and I have been having a really hard time. When I plug it in led 1 blinks twice but never fully turns on, it only does this when I plug it in then it imminently stops. The PSU does make a slight buzzing noise but nothing noticeable. I have replaced the PSU with a newly bought one from eBay. I have already also tried different RAM. Here is a video of what happens when i plug it in.