Any problems with buying a used Wireless router?

[vortexmak]

Hi,

Are there any concerns with buying a used wifi router ?
The way I see it, routers have no moving parts so if the reviews are good, used ones should show the same performance as new ones.

 

[System Error Message]

I dont see why a used one would have less performance, as long as you update the firmware and perform a factory reset.

 

[vortexmak]

Yeah, did both.
But I heard that capacitors dry up and the NAND flash wears out sometimes

 

[Razor512]

It depends on how the router was used. e.g., did the user install custom firmware which constantly logged data to NAND (I know that caused issues with the WRT54GL routers after a few years)

It also caused some issues with newer routers where constant writing to the NAND causes this list to grow

AND device: Manufacturer ID: 0xec, Chip ID: 0xf1 (Samsung NAND 128MiB 3,3V 8-bit)
Spare area=64 eccbytes 56, ecc bytes located at:
2 3 4 5 6 7 8 9 10 11 12 13 14 15 18 19 20 21 22 23 24 25 26 27 28 29 30 31 34 35 36 37 38 39 40 41 42 43 44 45 46 47 50 51 52 53 54 55 56 57 58 59 60 61 62 63
Available 7 bytes at (off,len):
(1,1) (16,2) (32,2) (48,2) (0,0) (0,0) (0,0) (0,0)
Scanning device for bad blocks
Bad eraseblock 31 at 0x0000003e0000
Bad eraseblock 254 at 0x000001fc0000
Bad eraseblock 484 at 0x000003c80000
Bad eraseblock 493 at 0x000003da0000
Options: NO_AUTOINCR,NO_PADDING,CACHEPRG,COPYBACK,NO_READRDY,BBT_SCAN2NDPAGE,


Other than that if it doesn't look like the NAND was constantly rewritten then they will generally be fine, though make sure there is a return policy since there is no warranty.

During your initial testing, you will want to do some extended stress testing to make sure things are stable. (I have seen many people keep their routers in a closed cabinet where the unit essentially cooks, and then when it reaches a point where it hands and needs to be restarted regularly, they decide to sell it.

You can usually stress a router by connecting some USB storage and then backing up like 2TB worth of data to it using 1-2 systems (using WiFI), the CPU load will be pretty high and the router will use use its full current draw.

 

[stevech]

I'd buy a $50 ASUS before a used or "refurbished" item

 

[vortexmak]

AND device: Manufacturer ID: 0xec, Chip ID: 0xf1 (Samsung NAND 128MiB 3,3V 8-bit)
Spare area=64 eccbytes 56, ecc bytes located at:
2 3 4 5 6 7 8 9 10 11 12 13 14 15 18 19 20 21 22 23 24 25 26 27 28 29 30 31 34 35 36 37 38 39 40 41 42 43 44 45 46 47 50 51 52 53 54 55 56 57 58 59 60 61 62 63
Available 7 bytes at (off,len):
(1,1) (16,2) (32,2) (48,2) (0,0) (0,0) (0,0) (0,0)
Scanning device for bad blocks
Bad eraseblock 31 at 0x0000003e0000
Bad eraseblock 254 at 0x000001fc0000
Bad eraseblock 484 at 0x000003c80000
Bad eraseblock 493 at 0x000003da0000
Options: NO_AUTOINCR,NO_PADDING,CACHEPRG,COPYBACK,NO_READRDY,BBT_SCAN2NDPAGE,

How did you test the NAND , are you using a custom firmware?

 

[Razor512]

depending on the router, it will do an automatic test during the bootup. To view it, you need a serial adapter (I use a cheap 60 cent USB serial adapter that I got from ebay) (had to use it a ton of times to help reflash my R7000 router due to a ton of unstable tomato builds which prevented it from booting after trying to use the webUI to flash.

anyway, during the bootup there will be a point at which it tests the NAND in order to find bad blocks and avoid using them.

 

[sfx2000]

Are there any concerns with buying a used wifi router ?
The way I see it, routers have no moving parts so if the reviews are good, used ones should show the same performance as new ones.

Anything less than 12-18 months old, you're probably ok... after that, power supplies (both internal and external) tend to start going bad...

 

[azazel1024]

Make sure they changed the capacitor fluid at the recommended intervals and you should be fine.

 

[Razor512]

Sadly, the fluid in the capacitors does not seem to be user replaceable, though with some wire cutters, you can take one apart.
https://c1.staticflickr.com/9/8510/8583976219_c24a146b1f_o.jpg

While on the topic of capacitors, if you have an old router with bulging capacitors, you can easily replace them. Simply look for the capacitance and voltage. You can generally go to a higher voltage rating, but you want to match the exact capacitance.

Capacitors are cheap, and with a soldering iron, solder, desoldering braid, and flux, you can replace the caps extremely easily.

In a decently build router, the electrolytic capacitors will likely be the shortest lived components (though if they are not getting very hot, they can last well over 10 years of continuous use).

 

[Ascaris]

I just recapped my Netgear WNDR3700v1 (which has been in continuous use since I bought it right after the model was first released... had to be around 2008) router a few months ago. It had low quality Ltec caps as original equipment, and three of four were bulged. It works very well now with the new caps.

My Netgear WPN824v2 has four low quality caps as well; in this case, CapXons. They are not bulged, but I have not used the router in many years, and even then it was not in service for long (I recall it was rebooting spontaneously a lot, and none of the settings I tried helped). The CapXons may well have dried out over all these years and could be waiting to bulge if I ever plug it in. (Failures without bulging can happen, I understand, but are uncommon.)

My Zyxel X-550 (a touch newer than the WPN824v2 as that was its replacement... also not used in many years) has low-quality Hermei caps, and my D-Link DIR-825 uses top tier Nippon/United Chemi-Con caps. (Edited: I had previously stated that the Zyxel used top tier caps.)

Perhaps you can determine what caps the router model you want to buy (interior images, reviews, etc) has in it (or at least what it might have) before you buy so that you can estimate the odds of needing to recap it. It really is not hard... this was the first device I ever recapped, and I was never a good solderer. I'm better now than I was, though!

Edit: Don't forget to order low ESR caps for the router. That is what mine had, and I am told all motherboards, routers, etc., are going to use low ESRs. Ultra low ESRs were not recommended to me, though, as they have significantly shorter service lives than low ESR caps, even in the top tier of quality, and they're not needed in a router.

 

[vortexmak]

Thanks for the info on the capacitors.
Just an update on my original post, I bought three routers off Craigslist
Linksys EA 3500 $30
Netgear R6100 $30
Asus RT-AC66U $40

The Netgear had some problems maintaining a connection but the Linksys and Asus are working perfectly. A pretty good deal I'd say.

 

[Ascaris]

Given that the two Netgear routers I opened had poor quality caps, I would guess that the Netgear you got might need this too. It might be able to perform well too. My caps for the router and an LG monitor that had failed (deader than a doornail failed) cost $10 shipped... they're quite reasonable if you have the soldering setup already.

 

[System Error Message]

regarding nand flash, they are as reliable as ssds and have the same write endurance. many embedded devices focus on reading only rather than writing as they dont use page files, swap or disk cache unless it is for a long term such as configs.

 

[coxhaus]

I have bought a lot of used Cisco routers, wireless WAPs and switches without having any problems other than upgrading the firmware.

On a couple I had to TFTP an image on the device but all worked fine afterwards.