Changing a fan on a power supply unit.

martin57

Hi folks,

I got a desktop computer a few years ago from PCspecialist. It is going well but have noticed lately that every few weeks when I switch it on there is a quite loud mechanical whirling sound from the psu. After a while it goes away itself, or even shutting down the computer and starting up again makes the sound go away. I have cleaned all of the inside of the desktop with compressed air, but still noise comes back.


The psu seems to be working fine otherwise, air coming out of the back of it. I rang Pcspecialist and they say its a FSP 600w quiet quad rail unit, which costs £59.
Its out of guarantee.

The Pcspecialist tech suggested just opening up the desktop and pressing upwards on the grill at underside of psu and also try to tighten up by a 1/4 turn any screws there.

I know that tinkering with a psu can be a very dangerous even fatal thing to do, but is it worthwhile for me to open up the bottom of the psu (after waiting at least 12 hours for it to discharge itself-is this enough) and try to change the noisy fan?

If so will the power cable for the fan have a connection to the inside of the psu or is soldered on there?

Any suggestions very much appreciated as well as from a safety aspect.

thanks
martin57

Figment

It's a straightforward enough job. Safety First - ensure you unplug everything first. You'll find a few screws (2, 3, or 4 generally) holding the PSU to the casing. Then there are usually four screws (accessible from the outside of PSU) that secure the fan to the casing, and a small 2 or 3 pin plug that clips onto the circuit board.

In good old Haynes manual form, replacement is the reverse of removal.

SteveJH200

To be honest it's not worth fitting a new fan - saying that I'm not even sure if you can buy them. Did you blow out the PSU with compressed air too? I find that usually helps - I use a 100psi jet of air but I hold the PSU fan still with a pencil or similar.

Figment

Maplin or a local Computer Repair shop should be able to supply.

fwor

Most of the PC PSUs that I've dealt with have the fan inside the casing, and they don't always make it easy to get inside. I've also come across one where the fan was wired in, and had no plug and socket.

You're right that some power supplies can be dangerous for some time after the mains is disconnected, but PC PSU's aren't like that. As long as you don't poke around inside with something like a screwdriver you'll be fine - with the mains disconnected there will be no voltages present that could electrocute you.

glosman555

There are many videos on Youtube that show how to change a PSU plus this one on how to change a PSU fan. http://www.youtube.com/watch?v=2u-JDMWD1_g

Mr_Toad

It could just be the fan bearing, they get worn over time. If you can get at it peel the sticker off the centre of the fan and put a little grease on the bearing, Vaseline is good, then replace the sticker.

Notmyrealname

SteveJH200 wrote: »

To be honest it's not worth fitting a new fan - saying that I'm not even sure if you can buy them. Did you blow out the PSU with compressed air too? I find that usually helps - I use a 100psi jet of air but I hold the PSU fan still with a pencil or similar.

Its not worth spending £2 on a new fan but instead is better spending £30 or more on a new PSU?

And yes you can buy them. Even Maplin sell them.

The fact you don't think you can buy them tells us all we need to know about the validity of your comment.

Notmyrealname

fwor wrote: »

You're right that some power supplies can be dangerous for some time after the mains is disconnected, but PC PSU's aren't like that. As long as you don't poke around inside with something like a screwdriver you'll be fine - with the mains disconnected there will be no voltages present that could electrocute you.

Except those present in the very large capacitors.

Keep metal things away from the large cylindrical things and you'll be fine.

SteveJH200

Notmyrealname wrote: »

Its not worth spending £2 on a new fan but instead is better spending £30 or more on a new PSU?

And yes you can buy them. Even Maplin sell them.

The fact you don't think you can buy them tells us all we need to know about the validity of your comment.

There is no need to be so damned rude - what the hell is the matter with some people on this forum. If you had left the last paragraph out then I would have thanked you for correcting me.

AirCooledHeaven

If you do fit a new fan just be sure to get it the correct way round, so it's sucking out, not blowing in.