Installing a Power Supply

[mike breck]

Here's a little guide, and some tips, I wrote for someone else.

Don't rush!

Replacing the PSU is easy and straightforward but it is a bulky component and could easily damage other components if you bang or scrape it against them.

Also, as you will have to disconnect the power leads and probably IDE cables from your devices, there is the potential of plugging connectors back in the wrong way.

So find the right moment and take note of which connectors go where, and the orientation of the connectors.

Switch off the PC and remove the power lead from the wall socket.

Put on your Anti-Static Wrist Strap (some just prefer to ground themselves by regularly by touching the exposed metal of the case - the choice and the risk is yours).

Start at the Power Supply Unit (PSU) and follow the coloured DC power leads to each drive and fan.

Unplug each and make a note as you do where each power lead is connected to.

For a beginners, labelling the power leads can be very helpful.
Or alternatively, you can put a dot or mark on the top surface of each connector which will show you which side is top.
When you put in your new PSU, you can refer to the markings on your old PSU connectors to help you work out the orientation.

Unplug the large 20 pin connector lead that plugs into the motherboard (mobo).

Undo the four retaining screws on the back of the PSU and remove the old PSU from the case. You may have to disconnect some of the IDE cables to give you room to do this.

Before you do, make a note of the the way the PSU is sitting in the case.

The new PSU will sit in the case exactly the same way.

For beginners, remember to mark any IDE cables with a felt-tipped pen so you can note where the cable goes and which way the connector is orientated to the device i.e. which way is "top".

Put your new PSU where the old one was.

Depending on the space in the case, you may have to unscrew the CD-Rom or CD-RW drive and slide it half out of the case, so you have enough room to slide the PSU in.

Don't connect the main power lead to the wall socket yet.

Connect the large 20 pin ATX connector from the PSU to the mobo.

If you have a P4 mobo then, depending on your mobo (some mobos like Asus have EZ-Plugs which allow you to use a standard Molex connector instead of ATA 12v), plug in the small, square, ATA 12v connector to the mobo.

Plug the a four pin Molex connector to each Hard Drive and CD-Rom drive.

The Floppy Drive uses the smaller connector and isn't always keyed very well; so make sure it's the right way round.

When reconnecting the power leads and IDE cables, try and route them in the most efficient manner to allow maximum airflow thro the case. Large rubber bands are ideal for holding groups of leads and cables together.

Make sure cable or leads are not in contact with any fans.

Check that the CPU fan is plugged in - if you have it plugged to the PSU instead of the mobo.

If the PSU has a dual voltage switch at the back, then make sure it is set to the correct Voltage for your part of the World i.e. US = 115v UK = 230v Anywhere else = check with your Power Supplier.

Double-check that everything is connected properly.

Power up.

If anyone would like to add anything to this, then feel free.

Our own David Risley, has also written a good guide here

http://www.pcmech.com/show/case/86/

HTH

[glc]

The only comment I have is the use of rubber bands is discouraged except as a temporary thing - the heat inside of the case will deteriorate them and they will break and fall apart. I prefer to use zip ties (cable straps) or plastic coated twist ties.

[piasabird]

A few months ago some of the people at the website for Tom's Hardware ran a test on a wide array of power supply's and found that many power supplies do not run well at their rated wattage. In other words they ran some power supplies up to the wattage ratings and they gave up or had poor results. Sometimes they blew or caught on fire. This is a good reason to get a power supply with overkill in mind.