In most cases, keeping these fans in working condition simply means replacing dead/malfunctioned fans with new ones. In some odd cases, however, replacement may not be the solution. This post describes one of those odd cases.
My main computer has a few fans in it. Two of the fans are of the unusually-large 200mm x 30mm type.
Recently, one of them failed so it's time to replace it with a new one. The following is what I purchased:
It is a BitFenix Spectre Pro 200mm fan. The size is identical to the old one from NZXT. Speed is slower (1100 vs. 900 RPM). I like how BitFenix is nice and smart enough to provide plenty of mounting options.
If none of those mounting holes fit (the situation I faced), I found that the 2-part frame can be disassembled for custom fabrication purposes. The outer, ring-shaped frame attaches to the inner frame via multiple clips. These clips can be undone easily with a small flat-head screwdriver.
Just as I thought this is a simple one-to-one replacement, the surprise comes when I power up the fan. The fan emitted scrapping and grinding noises as it was rotating. As I attempted to turn the fan blades by hand, there was noticeable friction. Since this is a new fan straight out of the box, it is certain that the fan is defective on arrival (DoA).
Such condition means the fan is garbage, but I wasn't ready to give up on it just yet. I suspect that the fan may work properly with the addition of a few drops of lubricant. To do that, I began by peeling back the label on the fan motor to reveal the shaft and bearing.
According to BitFenix, the fan employs fluid dynamic bearing (FDB) technology. To my understanding, FDB provides performance close to that of ball-bearing, but without the high costs in precision engineering. The following diagram illustrates briefly what FDB is like.
As I disassemble the fan in an attempt to lubricate it, a question came to mind - Does this fan really features FDB? Or just cheapo sleeve-bearing? The following are close-up shots on the shaft and bearing:
Anyway, there was a tiny bit of jelly substance in there. It was clear there was insufficient lubrication. I had to repack the assembly with grease. Once that was done, the noises went away. In fact, the rotor/blades seemed to rotate faster than before.
Prior to writing this post, I actually found quite a number of complaints on various online forums about similar fan problems with BitFenix, so I am not alone in this. While BitFenix is nice to exchange defective fans (from what I read; not what I experienced, as I am not interested in an replacement), I think the need to re-lube a new fan by the user is simply unacceptable.
To put things into perspective, the two fans shown above are much heavier in construction and much powerful than the BitFenix fan. These fans utilizes ball-bearing, which is known to be noisier than FDB. Still, they run smoothly without any weird noises.
All things considered, I would avoid buying BitFenix fans. The one I have now stays, but I doubt it will run for long. Its blue glow (from 4 built-in LEDs) is somewhat attractive. I leave them off though.
