1-Use a paper clip to short pins number 14 (Green wire) and pin number 15, 16 or 17 (Any Black wire). It is advisable to attach a device to the Power Supply such as a fan, a hard drive or and optical drive to perform the test because some PSU need a load to work or some PSU fans do not spin when the PSU is cold. This test does not check all voltages going trough each wire, but it gives a clear idea whether the PSU is dead or not.
2-Connect the Power Supply Unit to the main and switch it on.
3-If the PSU fan spins or if the connected device shows signs of life, it means the PSU is likely to be in working order and the computer fault may lie elsewhere. If not your PSU need to be replaced. You can find a variety of power supplies on our web site www.evercase.co.uk
This simple test is performed at your own risk. It is perfectly safe to touch the paperclip as it does not carry a high voltage. After the test, it is advisable to leave the PSU untouched overnight to allow it to discharge itself as it may store a dangerous charge.