In desktop computers the PSU (Power Supply Unit) is a critical component and it does a job of providing DC voltage to all other components in computer. This PSU is basically a SMPS (switching mode power supply) and it can fail after few years of use. PSU fail more often if there are voltage fluctuations. What we mostly do is buy a new PSU and discard the old one. Did you know that this PSU can still work like new by just changing few components inside it! And good thing is that not many parts fail in SMPS and it can be repaired easily. So here is a DIY post on repairing the PSU. Before we begin please note that high voltage maybe present even when the PSU is disconnected from main power supply, so do not touch anything inside before removing all the stored charge. We will tell you how to do this when we reach that point of DIY.
Removing the PSU from cabinet
First of all we need to take out the faulty PSU from the computer cabinet. To do so, first of all disconnect all the connections from computer and open up the cabinet. Now you should see the PSU with bunch of wires coming out and connecting to motherboard, drives and all. Remove all these connectors one by one. These are made in such a way that they cannot be fitted in incorrect direction so you don’t need to worry about which wire goes where when re-fitting them. So just pull them out one by one.
Once all the wires are removed, look at the back side and you should see four mounting screws which are holding the PSU in the cabinet. Unscrew all of them one by one and before removing the last two screws, hold the PSU by hand so that it does not fall below and break something. At this point if you find dust on PSU and in the cabinet, you might want to clean it with soft dry cloth and a paint brush. Take the PSU apart. Put the computer cabinet cover back and forget it for a while.
Opening the PSU
Look at the PSU and on top you will find screws, unscrew them using a Philips screwdriver and keep the screws at a safe place. Now try to remove the PSU cover apart, if it doesn’t come, search for more screws. Sometimes there maybe some screws hidden behind stickers. Once you have opened the PSU cover, clear the dust with blower. Do not touch any part inside right now but do have a good look on any burnt sign on any part of PCB or parts. Look at the fuse if you can spot one, if its blown, make sure you have a spare one ready but do not replace it yet.
We will continue this DIY in part 2