For most "normal" users, there is no way to conclusively test a PSU. This is because to properly and conclusively test a power supply unit (PSU), it must be tested under a variety of realistic "loads" then analyzed for excessive ripple and other anomalies that affect computer stability. So it takes a qualified technician using an oscilloscope or power supply analyzer - sophisticated (and expensive) electronic test equipment requiring special training to operate, and a basic knowledge of electronics theory to understand the results. Therefore, conclusively testing a power supply is done in properly equipped electronics repair facilities.
For "normal" users, the best way to test a PSU is to swap in a known good supply and see what happens.
While not conclusive, I keep a PSU Tester in my tool bag in my truck for house calls. The advantage of this model is that it has a LCD readout of the voltages. With an actual voltage readout, you have a better chance of detecting a "failing" PSU, or one barely within the required ±5% tolerances as specified in the ATX Form Factor PSU Design Guide (see “Table 2. DC Output Voltage Regulation” on Page 13).
I am not a fan of using a multimeter to test power supplies unless you are an experienced technician. To do it properly, that is, under a variety of realistic loads, the voltages must be measured while the PSU is attached to the motherboard and the computer powered on. Plus, most multimeters, like plug-in testers, do not measure, or reveal any unwanted and potentially disruptive AC components to the DC voltages.
So if you suspect a bad PSU, I recommend borrowing a PSU from another system, if you don't have a spare laying around. Just make sure it has sufficient power to support your computer. Otherwise, most better repair shops will test your supply for you for a nominal fee.
ok this has explained a lot in great detail I must add. Thank You Very Much for your Time and answer to my question. Myself being a "computer" noob," will try swapping and nothing further more.
another good 'yard stick' or rule of the thumb is before you purchase a PSU is to go to JonnyGURU.com an use the reviews as they really put PSU's through their paces along with what type of capacitors and pcb's are used an even how it is soldered.
BTW they don't sell or recommend things they just test what's out there and give non-biased opinions.
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