So to keep myself entertained over summer I considered doing some small electronics projects, most of which I haven't finished yet. I figured this one would be pretty cheap, and cool if I could pull it off. And so with no amount of planning whatsoever, I happened to make it work. I think. I post here what I did with this router in case any owners happen to find this page on google after hearing about issues with their WRN854T.



This is a great router...Kind of. Draft-N 300mb/s wireless and gigabit ports was way more than I could ask for. You can find this router on the internet for about $50, which seems almost too good to be true. I bought mine for $30 on ebay. There is a caveat, however. After about 6 months of usage, the router gives users what has been dubbed the "Green Ring of Death" where the router will brick itself for no apparent reason. Contacting netgear about the problem will lead to them sending you the same router, which you'll have to replace again a few months later until you get sick of it.

It seems someone found a solution for it, kind of. This blog shows how to unbrick the router, which is more or less the fault of the wireless card inside crapping out. The solution is simply to rip the wireless card out, essentially giving you a four-port gigabit wired router that works instead of a completely broken wireless router.

However, after searching around a bit more I found This post on the OpenWRT forums. To save you a link click, the contents are as follows:


I've got two suggestions regarding this router if you're serious about trying to use it:
1) Throw away the flakey Netgear/DVE wall-wart/power supply. Seriously. Replace it with any 9VDC or 12VDC 800mA to 1200mA traditional power supply. This will resolve a multitude of hardware restarts caused by power problems. Here's a new/surplus Netgear supply at allelectronics.com for $6.75. (The same power supply problems occur with the WNR834B v1 and v2 refurb units recently sold through Fry's and Geeks.com. Many of these included faulty power supplies.)

2) Install a 25mm (1-inch) 5VDC fan and power it from the console port's GND and Vcc 3.3VDC pins. Mount it above the top of the circuit board to pull air up from the bottom and over the CPU and wireless. The heat generated by this Marvell TopDog chipset hmm is unbelievable. allelectronics.com stocks this fan for $4.35, about half what the R/C car suppliers charge for one.

So I decided, what the heck. A gigabit wireless-N router for $40 is pretty sweet even if it lasts 6 months. I ordered it from ebay and it came in pretty good condition, except it was missing the bottom base and the cat6 cable it came from, but I didn't really care.

I also bought these components:
5volt 35mm fan( the 25mm was sold out at the time. This one works really fantastically though, I would recommend it over the 25).
A small heatsink for the marvell chip
The wall transformer previously suggested

So after waiting a bit to receive the packages...
I open both the boxes I got in the mail. The first thing I noticed was how dinky the stock power supply was as compared to the one I ordered. I immediately chucked it in my box of random electronics.



Next thing I did was open it, which required me to break some of the screws holding it together, reavealing this:

(I'm taking this picture from the Imovedtolinux blog I linked to earlier)


The two bigger chips without a heatsink to the bottom of the picture are the culprits of the overheating issue. To test this I plugged the router in and let it run for about 5 minutes, not doing anything. Sure enough, I hovered my finger above the Marvell chip and I could tell it was putting out a tremendous amount of heat.

So I immediately turned it off and got to work. My first order of business was attaching the heatsink to it using some thermal paste and superglue. It proved to be a little big, as it covered all of the marvel chip with some room to spare and half of the rectangular one next to it (some sort of RAM chip? ).

(you can see the large heatsink where the marvell chip was. A smaller heatsink might have been better, but whatever. It works fine. )

After the glue dried I turned on the router again and waited a few minutes to see if it had done anything to help cool the chip. It did, and by a lot. It was still generating a pretty ridiculous amount of heat, but even after waiting 20 minutes I could still comfortably touch the heatsink.
I wasn't satisfied though. So now it was time to attach the fan.