What causes the power supply to get too hot?

The biggest single cause I find for that kind of heat is resistance along the lines of current. A connection becomes slightly loose or a little corroded causing resistance to the flow of current. Resistance to current flow creates heat. Of course I can't say for certain that's the cause of your problem but it is a common source of heat in electrical and electronic systems.

I would say it's the power regulation section. In taking apart some computer power supplies, I've seen power transistors and voltage regulators that were heavily heatsink'd. They are most likely the culprit, but it could also be a transformer, though at the power the PS3 operates, that's most likely not it.

Same problem my ps3 ceche01 power supply gets hot I get error code 80010510 after updating a game on the ps3 (disc) so i launch the disc after updating and i get that code i looked it up and it seems that code is a internal power hardware failure ik how to try and fix but i hope it's nothing else causing that problem too occur