Over the years I have replaced many failed computer power supplies and have learned how to diagnosis, whether a bad power supply is the cause of computers failing to boot. When reader John M. contacted me about the problem he was having with a computer that would not start, I thought I would share his comments and my recommendations with you.

Reader John M. asked the following:
‘I awoke on Monday morning to find my trusty desktop computer failing to start. I smelled a strong electronic smell and noticed the fan on the power supply not turning. Is there a way to tell if the power supply is bad or if it could be something else wrong? If it is the power supply which one would you recommend that I buy?’

From the description that John provided, I would be about 99% sure that it was the power supply that is the culprit because of statement ‘strong electronic smell’. Another clue was ‘the fan on the power supply not turning’. In my experience these two facts would indicate a bad power supply as the culprit.

How many watts should the new power supply be? Over at Newegg they have a simple to use power supply calculator. You enter in the type of CPU you have, how much memory is on board, the type of motherboard on the system, video display adapter, hard drive and type of ROM device. If you have more than one hard drive, video display adapter or more than one ROM device, you can add additional devices before completing a final power calculation.

Most standard OEM systems, from companies like HP, Dell, and the rest, need at least 300 watts to function properly. If you believe that you may be adding more memory, another hard drive and a higher quality display adapter some day in the future, you may wish to get a power supply with more wattage. The next decision you will need to make is how much you want to spend. You can buy inexpensive power supplies for $20 or less.

I recommend you spend a little more money and get yourself a good, reliable unit that will provide you with the best performance. I have been using and recommend the Thermaltake 430 watt computer power supply. The units can be purchased from Amazon for about $41. Newegg carries this make and model as well.

What I like about this Thermaltake unit is that it comes standard with two built in fans for added cooling. The unit also comes with a black cable sleeve which is attractive and also provides better airflow inside the case. The computer power supply unit from Thermaltake is quiet, performs well and is an exceptional value when compared to other power supply units.