Re: What are you using to test your power supply?
We use a Digitus unithttp://www.digitus.info/en/products/acc ... -da-70601/
Works admirably with LCD readout and connections for all current mainsteam PSU connectors, has beeps for failures, but doesn't differentiate between 40-pin and 44-pin, so when testing a 40-pin, it will beep because it thinks some voltage inputs are not working.
When the voltage runs high, it is normally a sign of damaged e-caps, when it runs very low, it's the transistors, but this unit and most others I have seen is/are incapable of determining the current, therefore, it/they can not determine the "wear" state of the internals.
In short, these devices are only useful if the operator already has a good understanding of computer hardware in the first place, and they may be more useful to measure voltage in real-time if it were possible to connect them in parallel, but as the ones I have tested automatically short pins 15 & 16, this may not be the best option.
You can always use a multimeter as I have done for many years to get more accurate readings, but I do not totally agree with the author in the following page because power supplies only display their true status when under load and free-running a power supply without a load is not recommended by a number of electronics service agents.http://pcsupport.about.com/od/toolsofth ... imeter.htm
I have only been caught out once though, that was when my multimeters battery was dying. The voltage readings kept climbing and it had me dumbfounded for the best part of half a day until I tested another PC with the same results, that's when I reaslised it was my multimeter.