I have an important update on the silent cooling post. My fan sometimes stopped running and needed some help to run again. Please read the warning with further information and updates.

UPDATE: I have replaced the resistor with a red LED. Read more in the updated post.

The hardware modifications are finished and I even did some temperature measurements to make sure everything works well. The following articles are new:

• GuruPlug Fan: Some technical information about the fan
• Open the GuruPlug: Just some information on how to open the GuruPlug and a picture of the inside
• Improved cooling: How to place the fan in a better position
• Silent cooling: How to slow the fan down to decrease noise
• Temperature measurements: Some temperature measurements with different setups

After a while with no new blog posts and no new articles, I am back with some hardware modification to make my GuruPlug more quiet. The best idea I found is the idea from this forum thread. I like the idea mainly because the inside of the GuruPlug is not modified a lot and also the appearance does not change a lot. In addition, the airflow is quite perfect since it flows through the whole plugcomputer cooling all the components.

I just started the modification and of course documented with pictures for every step. The only thing I have to solve now is if I use the current fan from the GuruPlug (at lower speed) or if I should order a different one with sleeve bearing (should be more silent). I have to run some tests there and I'll post my results as soon as possible. The article can be found here.

To see if my GuruPlug works fine (since I heard about rebooting issues and network problems), I just let it run over night, of course with my USB-fan running to assure a good air flow. The next day, everything was fine as far as I remember but when I tried to connect to my USB hard drive, I figured out that my USB ports don't work any more. There is no 5V power and also an external USB-drive does not work, neither does the SD card.

Now I am wondering what could have happened. Did the constant 80mA of the USB-fan destroy the USB-interface? That should be impossible since the USB specification requires a current up to 500mA, and it's running on my PC's USB for a few days now without problem. Is it a heat problem which made my USB die? or did I mess up some configuration? Since I do not want to loose warranty I did not open my plug yet. It might just have burned some part which is easily replaceable, but if I can't fix the problem without opening the case, I will first try to return it before I do anything else.

To figure out if I messed up the configuration, I decided to re-flash my GuruPlug. This is also a great possibility to get to know the boot process better and get some insight into the file system. The tutorial I am following is the reflashing-tutorial on plugcomputer.org. It seems to work, but I am having some troubles getting the root file system to the plug using tftp. Here are my experiences with tftp and the installation process. I also added a short tftp-tutorial.

Cooling your GuruPlug might be an important criteria if you have one of the recent ones. It seems to be a problem with the design since there is no heat sink and not enough space for air exchange. I hope we would get further information from GlobalScale. It seems like they are redesigning a few things. This post shows some e-mailed information from GlobalScale.

Here is another interesting thread on the NewIT forum, since it describes some problems people have and there are also some solutions with some interesting pictures (it seems like you have to be logged in to see the pictures...).

My solution so far is to cool the GuruPlug housing from the outside with a 12cm 12V fan using the 5V of the USB-interface. Of course, I share my idea and wrote a small tutorial about my USB-fan.