Monday, December 21, 2009

Did you see a sign on my door that says "Dead capacitor storage"?

With apologies to Quentin Tarantino...

For a 10-year-old problem, the capacitor plague has been bizarrely present in my life recently.

It started a couple of weeks ago when a coworker offered me an LCD TV that was "flaky" as scrap (my scraphound predilections are by now legend among those who know me). Being the upstanding gent I am, I pointed out that it was probably bad caps, and I found and replaced the buggers for him.

A friend in Iowa sent me an e-mail, asking for help debugging a dead plasma he'd been gifted. He hasn't found bad caps yet but I'm fairly confident he will.

My PC was dead the other morning, when I got to work. Guess why?

A couple of months ago, I found a dead 17" LCD in the trash bin at the office. By now you should know how I fixed it.

A tweep I follow posted this article this morning.

This is fascinating for me in that it hits a number of points that people fail to understand about electronics:
  1. They wear out, but certain components are more likely than others to wear out, and fortunately, those components are easy to fix.
  2. There are two completely different realms for parts procurement. If you're dealing with quantities below, say, 1e6, you deal with the companies represented by distributors found in an Octopart or Findchips search. Above that, there is an entirely different group of manufacturers, and their components aren't cheaper because they grow on trees- they cut corners.
  3. OEMs don't care about long life, just long-enough life. If they save $1 per motherboard by using caps with a MTTF of 2000 hours rather than 10000 hours, and that gets them past their warranty period, that's fine with them.
  4. "High quality" electronics are not immune to this. ALL consumer goods (seriously, all of them) are dipping from the pool of cheap-o component makers. This is true from the $15 coffeemaker from Target up to a $2000 plasma TV, from brands like Coby all the way up to Dell servers.
  5. If you're making a product pulling from the Digi-key sourced manufacturers, the quality of component you're getting will be much higher. Replacing a burst cap with one from DK with similar specs is going to get you a long way.
I'm wondering how many otherwise perfectly good consumer electronics items are in landfills because of this issue.

So, take heed- most likely, a failed cap lurks in that dead PC, somewhere. It's an easy fix that can bring lots of valuable electronics into your life.

1 comment:

  1. Hi. A very telling post. Kudos!

    I recently resurrected 3 dead-as-a-doornail Dell LCD monitors. One of them had 1 dead cap in it; one had 3 dead caps in it. The third one, oddly enough, had no dead caps. In fact, I couldn't find anything wrong with it at all, and when I reassembled it, it came up running. Go figure.

    All of the bulging caps, btw, were 1000 uf, 10 VDC. I tend to replace them with caps that have slightly higher voltage rating; but I have been advised that there could be ESR and/or ESL issues with some designs, so it may not be a great idea to push the rating too high. 16VDC is quite sufficient.

    I could almost wonder why capacitors are the culprits so much of the time, but: resistors are unlikely to fail if not stressed, inductors are just pieces of wire & thus not likely to fail at all, and I guess most semiconductors have far greater MTTF than most electrolytic caps, especially cheap and/or underrated ones.

    I'll be keeping my eye out for more "dead" monitors, and perhaps "dead" computers as well.

    Best --
    jon

    ReplyDelete