PlayStation 3 Super Slim no power at all

I have a PlayStation 3 Super Slim that I brought off eBay. I want to try to fix it. It doesn’t power on at all. I took the console apart it looks good. But I am no expert. I will buy a new power supply for it. No lights come on at all. No red light, no yellow light. It has a hard drive. I want ti know what could cause this.