Capacitor Plague

As part of our completely overkill home network, I’ve got a couple of managed Linksys business-class switches (one SRW2016 and one SRW2048). They allow for me to do helpful things like VLANs, spanning tree, pretty graphs from SNMP data, and the like. Their web interfaces are crap, but aside from that, they’re fairly capable devices, and work well for the most part.

Well, let’s just say I had two switches. Now I’ve got, say, 1.25 switches. The SRW2048 has recently descended into uselessness, spending a good 20% of its time rebooting, locked up, and in other states where packets are not properly forwarded. It started occurring last week, and has accelerated in the past two days:

# zcat messages.1.gz | grep dist1 | grep "Cold Startup" | wc -l
6
# cat /messages | grep dist1 |  grep "Cold Startup" | wc -l
13

This makes me mildly annoyed, to put it mildly. The affected switch provides connectivity to most of my house. It services pretty much everything except for the server gear, which utilizes the SRW2016. Thinking that the switch might have been having issues with dust/animal hair clogging things up, making it overheat, or perhaps shorting something out, I opened the case up to see if I could give it a good cleaning. I was somewhat surprised to see a generally clean interior (nothing in our house is free of pet hair). What I did see was a fair number of bulging capacitors, and at least three or four that had visible signs of leaking dielectric compound. Lame.

If I had to guess, I’d say that my switch is infected by the capacitor plague, a rash of electronics issues caused by poor-quality components from a set of capacitor manufacturers. It’s been a general pain in the butt for almost a decade now, and it seems as though it’s now affected me as well.

The switch is valuable enough to me that I am thinking about purchasing a whole new set of the various capacitors present in the switch and attempting to replace them. They’re all fairly large, so I may actually be able to pull it off without melting the board or any other components attached to it.

EDIT: Of capacitors displayed in the following picture, 13 are either visibly leaking dielectric or have bulged. There are 33 capacitors visible on the board.

Capacitor ICU

  1. Check the voltage on those caps. Sometimes overvoltage can make them bulge. It makes the dielectric boil. I know. Once, at work, we made some noise emitting capacitors with a high voltage power supply. Popped a fluorescent tube overhead with one.

    • I’m not sure what they would even be rated for. I guess that would be part of figuring out what replacement parts to order, eh? 🙂

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