Posted by: Mike | April 28, 2009

How I fixed a broken Linksys SD2008

**UPDATE 4/28/2009**

Got another SD2008 in today.  The power light came on but no link/activity lights.  It had what looked like to be the same circuit board, however the 270uF 25V caps were in different locations. They were all swollen.  The 1000uF 25V caps were fine as they were on the previous one.  Used my last 4 270’s from the batch I bought to fix it and am writing this post across it now.  What took a great deal of time before took me about 15 mins this time.  Partly I was already set up, partly I knew I was best off using my $10 radio shack desoldering iron, adding a little solder to get more flux in there and then extracting much more cleanly.  Then work on the holes a bit.  Finally push the new caps through and solder all in place.

An easy fix.  I’ll keep my eyes open for dead out-of-warranty Linksys switches in the future.  I just bought a big batch of assorted low-voltage capacitors that should come in a week or so.

**ORIGINAL POST**

Lately I’ve noticed that the Linksys Gigabit switches we’ve sold last year are dying at an alarming rate.  Usually all ports will light up or some will not work.  I took one small 8 port (I have to say, most have been the rackmount 16’s), cracked it open, saw the problem and actually fixed it. Yay!

First the problem: on this one it would work for about 10 mins or so, get warm, and then all the lights would go green and nada.

Now we have to open the thing. On the back where the ports are you have to remove the plastic bezel.  There are two metal tabs holding it in on either side.  I used a small flathead to pry it out enough to pull the plastic bezel out one side at a time.  Next remove the plastic cover off the front.  I used the little plastic prying tools I use to take apart laptops, but a screwdriver would probably work here too.  Just press down on the metal casing enough to let the cover move forward.  Do this on the top and the bottom and it will slide off easily.  Next take the top and slide it off.  If you look on the sides you can see how the top and bottom interlock.  Finally remove the screws and you now can work on the circuit board.

On mine, two of the 470uF capacitors were swollen.  So I replaced all 4 of them.  I’ve marked them with red X’s in the photos.  Make sure to get the polarity right. It is nicely marked on the board.  If you forget just look at th smaller caps.  I had to add a little solder in order to remove the existing components.  This is one of those times my cheap $10 radioshack desoldering iron came in handy.  The two caps nearest the inside can be a little bit of a pain to get to and I never got mine to seat quite all the way down due to shoddy work on my part, but it fit fine back in the case and now works like a champ.

I’m shocked that Linksys was still suffering from this problem and have been generally unimpressed with the quality of their products the last two years, even for cheap network equipment.  But with about $5 worth of parts and a little bit of time I have a nice little switch to replace my aged 5 port 10/100 on my workbench.

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Responses

  1. Nice article, thanks. I too had one of these where the power light was on but no activity. After scanning your article I pulled mine apart and sure enough, the same 4 caps are swollen. Down to the sacred store tomorrow and with a little luck I’ll have a working gigabit switch tomorrow night 🙂

    It’s definitely a bit disturbing that Cisco are building these to fail just out of warranty.

  2. I fixed two units as well. Four capacitors were swollen in each unit (mine were 470 uF). I bought a lot of 24 Nichicon 470 uF 25 V for $10 incl shipping (maziz3). It is difficult to remove the solder from the hole even with Solderwick. I used a #60 drill in a small pin vise to hand drill them out. Pretty easy since the solder is soft. Thanks for the info. Just thought I would add some more.

  3. This article is so useful for me, I had the same problem and after check I found one of the 470uf capacitor was swollen. Plan to replace it soon.

  4. Thanks for the post. I too found this article very helpful. this swith is perfect for the home network.

  5. This worked excellent for me too. Thanks Mike!

  6. Perhaps you can tell me something that would be a huge help. I’ve an SD2008 with no power adapter. I do however have power supplies all over from amateur radio… so the question is, it the tip positive or negative? Also do you know if it is really sensitive since some actually put out 13.8 volts

    Rick

  7. Hello Mike,
    Your article was Great! I fixed 2 units so far with 470UF capacitors.
    Just had to say thanks for your post.

  8. Thanks alot for your article! I got two of these babies, both not working (power LED on, sometimes activity LEDs flickering). With your instructions peace of cake… 🙂
    I’d just recommend to mark the polarity before desoldering the defective caps.

  9. Hi Mike, thank you for reporting how to fix “yet-another-faulty-cap-issue”. (So far I’ve repaired several LCD monitors, power supplies and other devices by replacing swollen caps).
    I got a used SD2005 ver 2.1 yesterday, and my curiosity brought me here to find out how to disassemble it. My unit still has non-swollen caps – apparently because the chip produces less heat (and using lower current), compared to SD2008.
    My final word is to recommend using low-ESR (“switch mode grade”) caps whenever replacing capacitors in switch modes – otherwise you do as Linksys and build a ship that WILL sink ;o)


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