I have some power supplies of unknown rating. In a short answer from Rafal Powierski in How to measure max current of a power supply "How to measure max current of a power supply" (Since I cannot comment yet I started a new question) he is saying that amps (shorted) x 0,7 is roughly the rating. What if I use a variable resistance and measure the voltage drops? Is there no value e.g 5% drop to indicate that the supply is struggling?
These are sloppy ways to find the rating. Everyone who is looking for the answer to this question should do long term testing while present, checking temperatures.