Switching power supply toroidal heats more than 100ºC. Is it normal?
The output choke is cooking .The copper should be cool because you are not heavily loading the PSU .I have seen this before on a Chinese made Japanese designed PSU .The choke looks like it is made of powdered iron which for marketing reasons is now called something else .The powdered iron becomes more lossey with temp and time and then it gets hotter and runs away .You could replace the output choke with something more efficient .