Last weekend, I was at Fry's. They had the Promise NS4300N [reviewed] at $300, and 1T WD "green" drives for $220. For $960 before tax, I could do a 3 TB RAID 0, or a 1.8 TB RAID5 box. (The drives were one per customer, but the sales guy helped me out and I was with a friend, so I was able to get a total of three at the price.)
I brought it home and assembled it. I'm not a big fan of the proprietry plastic rails and proprietary screws, but I shouldn't be reassembling it often.
Then I powered the unit on. As reviewers have said, the stock unit is seriously noisy. It was easily the loudest of the pieces of equipment I ordinarily have on. I was—I thought — prepared: I had picked up a replacement 80mm fan for the unit. Changing the case fan was going to make me all better, right?
I had not yet read the various helpful blog and forum posts from others who did this - in fact, I didn't read them until after I'd written most of this piece! Before you go the route I went, you might want to read some of those posts as well, googling for "smarstor fan replacement" will start you off.
First challenge: the bits are not straight Torx bits, they're Torx security bits, with a raised nipple in the center of the hex. If you have a small flathead screwdriver and are gentle, you can use the nipple to brace the blade of the screwdriver into the hex and turn it. It's worth buying a set of Torx security bits for this project, though. There are quite a few Torxen in your way. This is a plastic case; the rear is not too hard to slip off, but be gentle.
Popping the rear of the case shows you the gig E port, the SATA card, the USB ports and the power supply, mounted below the hard drive enclosure. (Figure 1) (Sorry about the photo quality...all I had handy was a camera phone!)
Figure 1: View with rear open
The case fan power lead is a three pin lead with nonstandard outputs. I gently pulled the white lead base off of the NAS to better expose the leads. I tried various configurations until I sounded out where I needed voltage and ground to land. Then I reseated the the leads so that I could get the RPM lead fitted back into the headshell.
A small flat-blade eyeglasses screwdriver for will depress the backs of the fan power leads in the plastic shell enough that you can gently free the leads from the shell and reseat them in any order. Antec and Silenx both make quiet 80mm fans; Silenx has a 5/8" thick 80mm fan that fits the retaining clips in the Promise box perfectly. It spins at 1100 rpm and has a 14 db sound output. I had a variable speed fan that I was trying, but it was flaking - often refusing to spin at all; once I sounded out the power leads, I went for the fan which could, at least, spin.
Figure 1 above shows the stock fan clipped in place. It's a YS Tech FD128015EB and moves 45 cubic feet per minute at 37.5 db. Overengineered, or cheap? Probably both. But a good argument for going for the WD green drives; they're relatively cool running. The stock fan is rated at 4800 RPM, and the firmware thinks the fan's normal speed ought to be 2400 rpm, though—a much lower airflow. (The YS Tech fans that spin at 2600 rpm are rated at 26db and 24 CFM airflow.)
So, all good, right? Button up with the new fan and no more noise?
No. Button up, power on and hear the howling power supply fan. I couldn't find information on the power supply fan online, and have discarded the fan. It was at least as loud as the drive exhaust fan, though, a 1 and 5/8" unit which would fit better in a 1U rack server than in a living room.
What to do? Return the unit, keep the drives, and drop hundreds more? After doing some reading, I saw too many reviews of other NASes saying "this is too loud" to justify returning this unit and bringing in a more expensive one - and risk needing to modify that one, too.
The power supply is mounted below the drives, so I decided that if I were going to modify airflow, I was going to wind up placing the NAS upside down to let the warm power supply heat the room instead of the drives. I decided to cut the fan out and risk the powe supply not starting, working on the assumption that I could hack in a replacement.
I looked at the bottom of the case for a bit and saw that all the screws are accessible. (None hidden inside the case feet, for instance.) It was now worth owning a set of Torx security bits. I went all out and bought a $25 kit that included a lot of security bits, not just Torx, and a second 80mm case fan. My thinking was that maybe, just maybe, I could sneak the case fan inside the case above the power supply. If not, then I would fasten it to the top.
If you want to do the full fan replacement, start with removing all your hard drives. Make a note of where they were. A labeler will help. The case is plastic, and you do need to be careful, but it's possible to get the bottom and sides off the case. Unfasten the rear as above, then all the bottom screws, then slide the black side panel gently forward. You've just exposed the mainboard, so you want to be careful now.