Very Loud Noise from PSU


I recently gave my PC a clean-out as I had not done so for quite a while. After cleaning it out I reconnnected everything and switched it back on.

About 3 to 5 seconds after switching it on it started making a loud revving noise. On inspection it appeared to be coming directly from the PSU. I grabbed a can of compressed air and gave the PSU a good clean through, after a while the noise disappeared, and I was able to run the unit for a good 4 hours with no such noise coming from the back.

This morning I switched it on and the noise was back, despite further cleaning I could not get rid of the noise so I am not using it at the moment for fear I could damage something else ie: HDD’s etc.

I’ve read that this problem can be caused by a faulty fan, and that I would need the PSU replacing if this was the case. I also today found a small piece of thin metal that curls round, very much like a small paper-clip, This could be off one of the fans or something else intenal. :confused:

Could anyone offer any help? I’ve got some rather important work to get on with on there so it is killing me not been able to use it :frowning: , It also seems weird that I managed to stop the noise for a while and then it came back.

Anyone have any ideas/advice?

Many Thanks

Nafe. :slight_smile:

Probably the fan. If it quiets down after a bit, go ahead and use it while looking for a replacement fan or PSU.

It’s quite possible that something got inside the power supply and is intermittently hitting the fan. Other than that, the fans are the only moving part in the power supply so the fan must be bad if there is not something in there.
A couple of questions. Is the power supply under warranty? What is the brand, size, model etc. of the power supply? If it is under warranty, I would try looking through the fan grills to see if you can see a foreign object in there running. If it is not under warranty, I would pull the cover off the power supply (opening it will void your warranty if you have one). There should just be 4 or so screws holding the cover on. Be very careful what you touch as there are capacitors that store electricity even when it is unpluged. You should be safe turning the fan and looking to see if there are any foreign objects that are near the fan, that might be getting sucked in when it turns on.
Beyond that, you can start the power supply, with it out of the computer and disconnected, with the cover off. You might be able to see a little better what is going on. You should be able to unscrew the fan and hold it while it is running. If there is nothing rubbing the blade but the sound is from the fan, then its most likely bad.
You should be able to find info on starting the power supply out of the computer in this thread.

Thanks for the help,

I’m not sure about the warranty, I don’t think so as I’ve had the PC for quite some time now. The brand is Mercury and it is a 300w PSU the model is KOB AP4300X CE.

I’ve checked it out from looking through the grills/openings with a torch, I can’t see anything that is blocking the fans, I’m kind of avoiding taking the PSU out and looking in properly with it open due to the capacitors you mentioned but I may have a look just to see.

If the fan is bad what kind of power supply would I need to be looking at as a replacement? are they generic in the sense that I could buy any PSU as long as it is ATX?

Many Thanks

Most PSU units that old use a generic 80mm fan with a standard pc plug on it so if you really wanted you could just replace the fan and be good to go again.
Some you have to solder in the wires but many have a plug. But yeah I think I’d get a newer one with at least 500 watts or better and a high quality one at that. I bought a Nspire Xtreme power 750 watt from a friend who sells gear and it turned out to be the same unit that sells under the ThermalTake brand as the Tough Power 750 which in turn is built for them by Channel Wall or whatever their name is. Top rated, has active PFC, and is 80 percent efficient.
I paid 100 US for it so even though he gave me a deal I think it should be close to that price elswhere. Nspire has smaller rated ones that are also basicly made by the same people so that would be a good choice to start looking and get a great unit at a true bargain price.

If you are careful, its not that dangerous to open it. The main thing you want to be very careful of touching is solder contacts or the ends of wires (and most of the solder contacts should be down underneath the board). You could take the cover off and mess with the fan, being careful about touching other stuff. I’m not personally familiar with those mercury power supplies, but googleing, they look kind of cheap. you might be better off with a new one. I’m sure you are going to get some expensive recommendations. Frankly, I agree with those recommendations (I have been a victim of cheap power supply’s before), but if your budget is tight, you don’t have to spend 100$. I would get the best/biggest you can afford though. Here are some cheap ones that are good (stay away from the smallest ones), if you can afford more, I’m sure we can give some recommendations.

Thanks for the help guys,

I decided to go for a new PSU, The old PSU itself was quite old and I’ve been getting the feeling I needed something better. I opted for a Jeantech 400w PSU, So far so good, it’s quiet which is good. Only trouble I had while putting it in was the 4 holding screws, because of my case (or the PSU) the screw holes were obstructed as the holes in the case didn’t quite match the PSU holes, so some the screws wouldn’t fully go in, ah well. :doh:

Many thanks again for all the help, much appreciated. :slight_smile: :bow:



I have a strange noise that occurs every so often, and if I re-boot the noise disappears, I am not 100% if it’s the PSU fan or not. The current PSU is about 3 years old as it was a replacement.

I kind of take notes as to how many days since the last time I heard this noise, and it has been 20 days since the last time.

[QUOTE=cherrybox;2560604]I have a strange noise that occurs every so often, and if I re-boot the noise disappears, I am not 100% if it’s the PSU fan or not. The current PSU is about 3 years old as it was a replacement.

I kind of take notes as to how many days since the last time I heard this noise, and it has been 20 days since the last time.[/QUOTE]

You best to start a new thread as this one is way old and the OP has went and gotten a new PS so this thread is basically done with??? And you need to give us more info to go on??? Like what computer you have and PS and other hardware specs are in your system to really know what to look for and see what is happening…otherwise general request help won’t get much help as others won’t know what your problem is to narrow it down.

If it gets any worse I will start a new thread, but like I say it only every happens at cold boot, and when I re-boot it’s gone, I believe it to be the PSU fan though just by listening closely when the problem occurs. And when the noise disappears the computer can be on for ages that day with no problems.

I am not too sure the make of the PSU anyway.