Originally Posted by nawon72
Have you tried lubricating your sleeve bearing fans? They only last as long as their grease, or oil. But if they have been running for awhile without much, or any lubrication, then the bearing will be damaged to the point where you should replace it.
Ehume's Guide: http://www.overclock.net/t/773256/prepping-a-sleeve-bearing-fan-for-work/0_30
Using a light oil would probably be a good idea if your just trying to get your fan to start again. Then once the oil has absorbed into the sleeve, you an try grease, since it will last much longer(less maintenance).
Here is a technical article about lubricating sleeve bearing fans: http://machinedesign.com/article/grease-keeps-sleeve-bearings-lubricated-1007
Here is another good Sleeve VS Ball bearing article: http://www.comairrotron.com/cooling_fan_noise.shtml
It has a bit of a different perspective. Some key points:Open (Click to show)
"Most ball bearing fans are noisier by 1 to 3 dBA
over their counterpart sleeve-bearing fan. Also the additional noise is somewhat pure tone in nature. Therefore, the annoyance level is considerably higher than with the sleeve-bearing fan. This higher noise level is also in the higher frequency ranges, which makes it even more annoying.
"Sleeve bearing fans, generally speaking, can easily sustain multiple shocks
of 80 g's with duration of 11 msec without impacting noise at all. This is not true for ball bearing fans. Figure 3 shows what can happen to ball bearing fan noise if the fan is subjected to 40 g's (11 msec duration). This is a very important factor since the equipment manufacturer has no control over how this equipment is treated after the fan is installed, particularly in shipment. It is quite common for a ball bearing fan to be noisy before it is even used just from the handling of the equipment it is installed in
"Typically, sleeve bearing fan noise does not increase due to life.
This remains true up until the system begins to fail due to loss of oil. However, ball bearing fans can begin to get noisy in a very short time. This increase in noise is due to many facts, such as grease channeling, loss of grease, damaged bearing camouflaged by the grease, etc. Also, as time goes on, the grease may begin to dry out which allows for a very noisy fan, but it will continue to run for a long time. This brings up an interesting point: the reason for the use of ball bearing fans is to extend the fan life past sleeve bearings. However, if usable life were defined to end when the fan became noisy, it is quite possible the sleeve bearing fan would out live the ball bearing one
Quoted from here
I have not, unfortunately, but I have since sold off, gutted or tossed out all of my sleeve bearing fans so I no longer have any of them to try and fix.
Some of the Yate Loons I had (mix of low and medium speeds) ran for a year or longer before having the problem. My Scythe Slip Streams, on the other hand, started to whine and grind a mere 2-4 months of use. I bought five fans all at the same time from Sidewinder's years ago and literally one fan after another started to die!
It may have been a fluke or bad batch, but I RMA'd through Scythe, requested to trade up to S-Flex's, paid the difference and got better fans in my opinion (although, I have my issues with them as well).
My main issue was that I needed reliable fans that could be mounted horizontally (on radiators or intake/exhaust at top of cases), and apparently, this will wear out the bearings faster due to lubrication issues. Since then, I have only bought ball bearing type, and similar variant, fans. It's true, I do have to undervolt some of them (fortunately not all) to make them quieter than the sleeves, but I have been really happy with them all nonetheless as the noise profile is not as intrusive to me. To each his own.
With that said, I'm not averse to trying this new Z bearing variant.
Originally Posted by kidsafe
I think we are dealing with different magnitudes of ambient noise. Even with my eight 120mm Kama Flow 2 1400RPM fans and one 140mm Kama Flex 1200RPM fan
at 12V, an SPL 1M away measures <33dBA. At idle the SPL measures <26dBA.
I will admit that not all FDBs are created equal. The much praised S-FLEX fans were actually quite grumpy sounding if you actually put your ear close to the motor. They emitted a very distinct hum for sure. The Kama Flow 2s fortunately do not have this hum and are by far the most well rounded fans I've used.
As for the GTs, babying the voltages is a no go for me, especially when some of the fans have that harmonic resonance slightly offset. I also use a T-Balancer with target temperatures, and I'm fairly happy with the target temperature operating mode.
I agree about the ambient noise. I think further to point we also have different hearing as well. I'm like a dog, so I've been told.
My girlfriend tells me I don't listen to her, but I just can't hear what she's saying (or can I?
), but I can hear the tiniest, sharpest sounds.
Sorry, I do take back what I said about the Kama Flow 2's. I mistakenly mixed them up with what I have used in the past, which was the Kama Flex
Since the KF2 sounds like a newer, and improved line, I'll give it a try and pick one or two up on my next order of fans. I'm always looking to try out new stuff to make all three rigs in my apartment as quiet as possible.
I know what you mean about the GT's. I had to relocate the one AP-15, which does have the resonance, to another location on my case and run it on its own channel through my fan controller. Ever since then, I have not heard it squeal at all. If someone had several that resonated, if I were them, it would drive me insane.