Why is my PS4 making noise in rest mode?

Somewhat recently, my PS4 has started turning off while in sleep mode. When entering sleep mode, the console will make a chirping/squeaking noise (not a beeping noise, like it does when it powers on) for a few moments before turning off. When I power it back on it enters safe mode and says that the system wasn’t shut off properly. If I power the system off and on, instead of using sleep mode, everything is otherwise fine.

1. I’ve tried unplugging the system and letting it sit before plugging it back in.
2. I’ve tried rebuilding the database.
3. I’ve double-checked the power settings.

After my research online, I think its a power supply issue, but I'm not sure/

If it is in fact a power supply issue, how easily can I perform this repair myself?