I have a 1st gen PS4, which was plagued with power supply issues. It would keep turning off at random times for no reason. This would be followed by having to re-analyze and restore the system software just in time for the power to kick off again. Because my PS4 was out of warranty, Sony would not help unless I paid $150 up-front for analysis (Poor support for a well-known issue, if you ask me). I looked on-line and found numerous sellers of the replacement power supply, but IFIXIT had the best reputation, and even had step-by-step instructions of the replacement. Bonus: Even though I did not personally need them, they had links directly to purchase of the tools required.
Quick, Easy, Painless. PS4 works like a champ now. It took about 20 minutes total, and 1/2 of that was finding the right torx bit.
Make sure to verify you have the "security" torx drivers, otherwise it will be more difficult.