One of the easiest parts to replace and one of the more lucrative is the power supply or PSU. It's also very easy problem to diagnose. A customer calls and explaind that their computer will not turn. If the computer shows any lights or anything on the screen then the problem is not the power supply. The only light that may be showing is a blinking LED on the power supply indicating it's broken. Otherwise the computer won't show any signs of life. Here in California I can easily charge any where from $60 to $75 for this repair including the part. Used power supplies are easy to find in old discarded PCs, at thrift stores, or on craigslist.
The connections and size of the PSU vary, but are very similar and universal. The main connections you'll be looking at are:
- 20 or a 24 pin ATX connector on the board.
- 4 Pin (square) 12V connection
- 4 Pin Standard 5V/12V drive connection
- Sata connection (newer computers)
Some older PSUs may not have the connections yours requires. Luckily the wires are normally color coded and can be cut and rewired. An example is the 4 pin (square) connection. Not all PSUs have these. Cut the ATX connection off the old broken unit. Since there are 4 wires twist the 2 yellows together and the 2 black ones together. Grab an extra 'Standard 4 Pin' power connection and shove the yellow exposed wire securely in the slot with the yellow wire leading up to it and the same for black and then tape it up. This way you won't need to go hunting for one with this ATX connection. As always be safe when handling the PSU. The capacitors inside can pack a punch!