It’s getting hot in there…
September 18th, 2006 by ktula
My Thecus N2100 had always been running hot ever since i bought it in March this year. During a hot weekend in mid summer when the daily highs were in the mid to high 90s, i noticed the internal disk drive (HDD) temperature alarmingly hit 58°C. I took the drastic measure of shutting it down for the whole weekend. Consistently running disk drives at more than 50°C can’t be good for their reliability and the longevity of the disk drives in the long run. For comparison, the 2.5″ 60-GB Fujitsu disk drive in my first generation 17″ G4 Powerbook normally stays in the range from low to mid 40°C.
According to the specifications for my Seagate Barracuda 400 GB SATA disk drives, the drive case temperature should not exceed 69°C (156 °F) and the ambient temperature should fall between 0 and 60°C. The FAQ at Seagate defines ambient temperature as the temperature of the environment immediately surrounding the drive.
I have been researching the past week trying to come up with a good solution to cool my disk drives down. Initially, i took the lid off the case and had a floor fan blow toward case. This managed to bring the temperature down to about 39°C when the NAS was idle. Even when operating under load, the disk drive temperature would never exceed 42°C. This tells me that Thecus did not design the airflow within the case properly.
My guess is that the tiny vent slits in front of the case are simply not providing openings for cool air to enter the case. I decided to implement Leyton’s two-fan mod at the Thecus User Group forum.
I bought two Link Depot 40×40x20mm case fans and two three-pin Y fan cables at the local Fry’s Electronics on Saturday. To make a cut on the only side of the case roomy enough to fit the 40×40x20mm fans, i bought a Dremel rotary tool kit. I also bought two Irwin Quick-Grip clamps to hold the case in place when i am making a cut on the case. The Irwin Quick-Grip clamps are such a delight to use and they are so much more efficient than the old style C clamps.
The first thing i did was to remove the HDD cage from case. After that, i removed the four screws at the back of the base that were holding the stock fan in place. Next, i removed the motherboard from the case.
After keeping the case in place with the two Irwin Quick-Grip clamps, i used the drill bit attachment on the Drexel and made about 20 holes on the side of the case closer to the 128-meg memory module.
On the opposite side of the case, the only area in the case roomy enough to install additional fans, i cut a 80×40mm rectangular hole with the cutting attachment on the Dremel. The edges of the rectangular hole is not as straight as i like it to be, but for its intended purpose of fitting the two fans, it works fine.
After placing the motherboard back into the case and reinstalling the stock fan, i connected the fans to the only power source with the Y fan cables (sharing with the stock fan) and placed the fans in the cut area.
The first thing that i noticed after powering up the N2100 was the fans were running at very low RPM. I could barely feel the air drawn out by the fans. The result of this two-fan mod was very disappointing. The idle HDD temperature remained high, at around 47-48°C. When placed under load, the HDD temperature went up to 50-51°C. This was when the room temperature was probably around 75°C. I immediately realized that the problem of sharing one power source among three fans is reduced airflow. When my stock fan was the only operating fan, it would normally run between 5000 - 7000 RPM. With the three fans installed, it was difficult to get an accurate reading of the fan speed but i estimated that they were only running at between 500 - 1500 RPM. The Link Depot fan is rated to push 7.5 CFM of air and that’s probably when it is running at full speed. So having three fans installed was actually no better than having just the lone stock fan.
Late last night, i decided to try using just two fans - the stock fan and one of the two Link Depot fans. For the Link Depot fan, instead of having it move hot air out of the case, i flipped it around and have it move cool air into the case. To my delight, the idle HDD temperature went down to 41°C. When operating under load, the HDD temperature went up a few degrees to 44°C.
As shown in the graph above, the HDD temperature during idle system between 0310 - 1007 hovered around 41°C. To make sure that the fan blowing air into the case was indeed helping to keep the idle temperature low, i removed the Link Depot fan at 1007. The HDD temperature went from 41 to 46°C in 50 minutes. When i reinserted the fan at 1057, the HDD temperature started dropping and it went down to 41°C at 1214 and it was able to keep constant at that temperature until i started to write/read a 24-GB file at 1252. The load test ended at 1418 and the temperature gradually went down by one degree. The temperature near the N2100 was about 77°F (25°C) during the load test.
I am going to tape up the opening of the side of the Link Depot fan to see if that affects the temperature reading. If that does not have a detrimental effect, i am planning to aesthetically improve the look of the case by adding some metal mesh to both sides of the case.
Note: To capture the temperature data, i created a cron job on the N2100 and have it write the temperature readings to a file. This is the same temperature reading shown in the System Status page on the Thecus N2100 web admin tool.
Update: 9/18/2006 22:20
As the room temperature falls, so does the idle HDD temperature. The idle HDD temperature is now 37°C. The HDD temperature has never been that low.
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