Why the Playstation 4 turns on and quickly off?

The ps4 started having this problem when it turn on and quickly turn off. So I purchased another power supply from ebay So I went to install the power supply and when I turn on the ps4 it started loading but a strong burning smell started coming from the power supply and 15 seconds later it turn off. So I message the seller and told me that it could be a motherboard issue that could have shorted the power supply. Any ideas on what's the issue or solution?