I have never used a specialized tester for checking a PSU. I typically read the side panel info, check pinout and use a meter. I was looking at a couple of inexpensive options and it appears that they are really doing the exact same thing I am already doing with my meter.
Do any of the units designed for testing offer a setting in which it will apply a load to the supply?
Do any of the units designed for testing offer a setting in which it will apply a load to the supply?