PSU Fan slows down to a crawl

[monsterfurby]

During high load, I recently noticed that my PC had become practically an oven - CPU heat up at 100°C, burnt dust smell, the full programme. My search for the cause yielded a quick result: The PSU's fan was barely spinning, much slower than I could even move it by just blowing on it. It was not spinning down, however, but keeping this rotation constantly.

I restarted the PC only to find that the fan is *mechanically* capable of running at normal operational speeds - no trouble with connections or bearings apparently - for the first 10 minutes of operation, it runs perfectly well. It is only after some time of having the PC running that the fan goes down to barely anything again.

Does anyone have an idea what might be causing this? As I said, mechanically, the fan seems to be fine. Software shouldn't, to my knowledge, impact PSU fan speed. What else could be causing it to slow down this massively?

Also, is there any hope for my PSU? I wouldn't have much of a problem with my CPU or GPU melting, but the PSU is something I really don't want to take a chance on.

My DxDiag is here:
http://www.hanmun.de/DxDiag.txt

 

[maxwellmelon]

you should not be relining on just the power supply fan to keep your case cool. you should have at least one or two case fans even if there the general cheap $5 ones. to make sure you don't have any other issues going on open the side of your case and have a small fan blow in it and see if your cpu temps stay down. if they still go up to 100 degrees then you have other issues going on too. if there is a lot of dust in your computer you may try getting a compressed air can and blowing it all out, specially your cpu cooler as it should have no dust allowed to build up on it.

 

[monsterfurby]

Thanks for the answer: I have actually done that just recently, which took my CPU down to 45°C in near-idle, 50-60°C in normal and 70°C max under high load, which I guess is fairly acceptable although not great. Yet, I never experienced that extreme a heat increase until recently. The only thing that has changed is the PSU fan. Yes, my tower has absolutely terrible air flow, and yes, I guess there's always something that can be improved, but the acute problem coincided with my PSU fan apparently kicking the bucket.

I just now noticed that the PSU fan actually does run a bit irregularly under normal circumstances - in fact, it is fairly noisy and slows down for an instant every few rotations, even under normal circumstances. Is there any solution other than replacing the entire PSU? Could dust be causing this?

 

[maxwellmelon]

well it does sound like your psu fan is failing then. sometimes the fan can be replaced in the power supply unit but most the time you will have to just get another psu as the fan is hardwired in. just look for the wattage listed on the power supply and buy one that's the same or higher(it really wont benefit you to get one with a much higher wattage). there not that expensive for a new one but don't overlook the option to get a used one. just make sure what ever you get has all the connectors you currently use.

 

[Imre_2]

Is it possible to just spray some Q20 somehow ?

 

[Paperdoc]

Do NOT spray anything - especially oil! - into a PSU, or anywhere else inside a computer. OP's posts certainly describe a failed fan in the PSU, as maxwellmelon says. Many such fans are just the same as common computer case ventilation fans in the right size, so if you are "handy" with repairs, replacing it is not very difficult. It does require a bit of re-wiring and soldering usually, and you really need to know how to protect yourself from residual electrical charges inside a PSU. So if that's not in you skill set, OP, buying a new PSU might be cheaper than hiring a pro in a computer repair shop to do the fan replacement for you.

 

[DSzymborski]

Is it possible to just spray some Q20 somehow ?

Do not spray lubricant into a PC. Ever. Or even onto a fan. It's a bit like having dry eyes and deciding the solution is to pour moisturizing lotion directly onto your eyeball.

Also, please don't necro four-year-old threads without a really good reason.

 

[Imre_2]

Is it possible to just spray some Q20 somehow ?

Do not spray lubricant into a PC. Ever. Or even onto a fan. It's a bit like having dry eyes and deciding the solution is to pour moisturizing lotion directly onto your eyeball.

Also, please don't necro four-year-old threads without a really good reason.

What is the reason that oil should not be prayed in to a fan of s PSU or a Chasis fan for example.

 

[DSzymborski]

Is it possible to just spray some Q20 somehow ?

Do not spray lubricant into a PC. Ever. Or even onto a fan. It's a bit like having dry eyes and deciding the solution is to pour moisturizing lotion directly onto your eyeball.

Also, please don't necro four-year-old threads without a really good reason.

What is the reason that oil should not be prayed in to a fan of s PSU or a Chasis fan for example.

Because PC fans are not designed to require external lubricant. If the fan is failing, it's the bearings, not a lubrication issue. And fans are cheap, you replace them, you don't instead decide to have parts with oil on them spinning around and 2000 RPM inside your valuable electronics.

 

[Imre_2]

Is it possible to just spray some Q20 somehow ?

Do not spray lubricant into a PC. Ever. Or even onto a fan. It's a bit like having dry eyes and deciding the solution is to pour moisturizing lotion directly onto your eyeball.

Also, please don't necro four-year-old threads without a really good reason.

What is the reason that oil should not be prayed in to a fan of s PSU or a Chasis fan for example.

Because PC fans are not designed to require external lubricant. If the fan is failing, it's the bearings, not a lubrication issue. And fans are cheap, you replace them, you don't instead decide to have parts with oil on them spinning around and 2000 RPM inside your valuable electronics.

Cool, so u reckon i can just change the fan for this PSU?
I have a Cooler Master RS 750 ACAA - A1

 

[Paperdoc]

It is possible, but depends on a few items.

1. Is this unit still under warranty? If it is, opening it up and changing anything will void the warranty.
2. Do you understand repairs of electrical apparatus? Do you know how to discharge residual charges on capacitors safely? If you do not have experience in this area, there can be enough charge inside a PSU to kill you!! So unless you really know what you are doing, do NOT!
3. Are you skilled, mechanically (to remove, open, disassemble partially and re-assemble the PSU) and electrically (determining what leads to change, with correct polarity, soldering and insulating wires, etc.)? If not, you risk damaging your PSU and the rest of your computer if you make mistakes.

If are sure you can do all that, you will need to do the disassembly first to determine exactly what size fan you need to get as a replacement. Physical size is important, of course. Ideally you want a new fan with similar air flow capacity, but many fans will not have enough identification on them to enable you to identify it exactly and find its ratings, so you'll just have to guess. In most cases you will need a common 3-pin case ventilation type of fan (VERY likely not 4-pin), and will NOT need to make any connection to the speed wire (Yellow) of the new fan. When you're done, check to be sure the air flow from the fan us in the right direction - same way as the old one. If you got it wrong, you'll have to re-do the connections to the fan leads.