Router fan mod

A bought a router about a year ago, Cisco Linksys WRT310N.  It’s nice, but lately, it’s been getting really hot and losing internet connection frequently.  Without much preamble, I decided to take it apart to see why;

wrt310n without a cover
the router's true self

 

 

I left the router on for several hours, then tried to determine the hot spot(s).

 

After finding multiple too-hot-to-touch spots, I bought a VGA heatsink and an IR thermometer;

IR Thermometer
a cheapo IR thermometer
tiny heatsinks with thermo-pads
VGA RAM heatsinks

The temperature reading on the top surface of the router was 160f and quite hot to the touch.  These heatsinks were more difficult to find than I expected – it took a long time rummaging through Microcenter’s cooler isle to find.  It’s important to note that these are;

  1. small;
  2. uses an adhesive sticker to attach to the part in question.
heatsinks with adhesive
heatsinks with adhesive

A heatsink will only expose more surface area of the heated… surface.  I will need to find a small fan – this router will now use active cooling!

I tried to cover most of the hotspots with the heatsink – doubled up on the larger areas;

 

wrt310n with heatsinks
wrt310n with heatsinks

 

To get some parts, I looked into my spare parts bin to see what I can find.  I found an old motherboard(Pentium4 era).

a relic from the past - a small CPU fan
a relic from the past - a small CPU fan

 

I got a small CPU fan from there, it’s a 12V fan.

 

At this point, I stopped to search the internet – surely I can’t be the only one have thought of this… and surely enough, people have.  In fact, they have had this very problem on the same model router as I.  Some even mention that the router had heatsinks when they opened it!!! (strange, I didn’t have any heatsinks under the cover).  One thing I got from the internet was the idea to connect the fan to the POWER line(it’s also 12V, hey, what coincidence!)

underside of the power plug
underside of the power plug
soldered fan power lines
soldered fan power lines

While I was cannibalizing this motherboard, I decided to take the female plug off the board so the fan isn’t permanently soldered to the router.  Not an original idea – many others have done the same;

 

female plug on the motherboard
female plug on the motherboard
fan power plug
fan power plug

 

I then cut out a hole on the router cover to expose the fan and let the outside(read: cooler) air into the router; the only thing I did differently was that I wanted the fan to blow directly on the areas I’ve marked as the hotspots.  This meant the fan will be offcenter;

fan's ideal location
fan's ideal location
fan mounted outside the router
fan mounted outside the router

 

I’ll admit – I got impatient toward the end, hence the scotch tape on the fan.

 

And, to justify the IR thermometer purchase, the temperature I got on the surface of the router is a cool 78.8f!

 

This being a long post, I’ll add the afterthought(s) here as well.

 

Things to note :

  • The actual router is quite tiny, and looks very simple.
    • Can upgrade/extend the antannae?
    • Put it IN a PC case.  Seriously, a PC tower with a router INSIDE.  Sounds cool.
  • The fan is ALWAYS ON.  ALWAYS FULL blast as well.  Hmm.
  • The Verizon DSL modem is at a warm 118.8f!

Possible/additional mods :

  • Put a fan guard – the fan is outside of the router, and the blades are spinning, last thing I need is something to fall in and break the fan/router.
  • Fan on/off switch – I can’t imagine why, but maybe I should have a button/switch to turn the fan on or off?
  • Fan controller – overkill?  The fan is relatively silent(thank goodness P4 fan!), but I can’t help but feel maybe the fan ought to spin up only when it hits a temperature threshold.  I DO leave this for long periods of time.
    • If I’m gonna entertain overkill ideas, maybe a temperature probe and a small screen to display the temperature of the router?

 

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