So when I turn the ps4 pro on it goes on for a second, but the fans kick into overdrive and goes crazy and immediately shuts off. I’ve watched all the videos on how to take it apart, I cleaned it, put it together but it still does the same thing even though I didn’t miss any steps, I also replaced the thermal pads and paste but that’s didn’t change anything. It still makes the fans go crazy and shuts back off immediately, please tell me what might be wrong with it I don’t want to loose everything on it anything helps. 
Hi!
You could try changing the powersupply, not saying that it will help, but it could help 
Let me know if it works!