Cheap Electronics Suck!!! (Again!)

Discussion in 'General Electronics Chat' started by tom66, Apr 3, 2011.

  1. tom66

    Thread Starter Senior Member

    May 9, 2009
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    I went to my brother in law's house. He had a garage clean out. The rule was, anything I could grab, I could keep. That included an LCD monitor. A very nice Xerox 1280x1024 monitor. (not sure on diagonal size but it is big!) This monitor must have been £200+ new, as it was manufactured in 2005. So, this is the final part of my gaming PC, which has cost me so far £35 for a HDD. (Everything else was free. And there's a 5.1 PC surround system on the way too!)

    It doesn't work, though. You can plug it in and the blue power light will light up, then go out, and repeat this process. After a while, you do get more - the display starts working. It will display an image for a few seconds, but soon lines will form on the image and the display will go completely white. Here's a video.

    http://www.youtube.com/watch?v=-DhTFSTRwA8

    So, what do you think the problem is?

    It begins with "C" and ends in "apacitor". Yes, it's another case of cheap, bulging capacitors. When will manufacturers learn? Or do they know it will happen and they do it regardless so you buy a new monitor?

    [​IMG]

    These caps were well specified (470u 25V) for a 5V and 12V power supply. However, they are a cheap brand, which probably means their ESR and ripple current ratings were crap. They are also next to the schottky diodes for the power supply, which probably didn't help heat wise.

    Replacements have been ordered. All 470u 25V caps will be replaced with Panasonic 470u 25V.
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
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    One of the guys at the sidewalk sale sells only low ESR capacitors, the kind used in motherboards. He seems to do well.
     
  3. krazytech

    New Member

    Apr 3, 2011
    9
    0
    Hi
    Chinese caps Xunda do they have a high failure rate?
    Did you test with a ESR meter ? what is the normal ESR?
    Are you going to replace all of them or just the dome ones?

    also would it be better to spend the little extra to replace with a 470u 35V or 50V?
     
  4. Adjuster

    Well-Known Member

    Dec 26, 2010
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    Lots of equipment manufactured between 1999 and the mid-noughties suffered from the so-called capacitor plague. I would guess that many equipment manufacturers had no idea that there was a problem, at least not initially. It seems that a considerable volume of cr*pacitors got on to the market before the issue was noticed. http://en.wikipedia.org/wiki/Capacitor_plague

    As manufactured, the "bad caps" were not obviously faulty, and may not even have had particularly high ESR. The problem was long-term breakdown of the electrolyte, with generation of hydrogen gas. In time of course the performance did go bad, with rising ESR, bulging cans, leaks etc.

    I think it likely that the recent proliferation of new component manufacturers in Asian countries will lead to much more trouble of this kind. Until and unless a sensible attitude to quality evolves in these regions, a problem of poor quality / fake goods is likely to persist.

    Perhaps I am being prejudiced here, but I think that in some of the countries now becoming the workshops of the world corruption is so ingrained that it it may be difficult to imagine anything other than a decline into chaos. If this happens to destroy your PC it may be a nuisance, but what if it's your car brakes, the engine of the aircraft you fly in, or the control equipment for a nearby nuclear power plant?
     
  5. tom66

    Thread Starter Senior Member

    May 9, 2009
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    I'm going to replace all of them. The Xunda caps do have a high failure rate. I've seen several similar power supplies with the same failed capacitors, in varying degrees.

    I'll replace them with 470u 25V. This is because the supply has only 5V and 12V outputs (as well as a backlight.) So they are well spec'd, but they are cheap crap capacitors.
     
  6. krazytech

    New Member

    Apr 3, 2011
    9
    0
    Fake Goods.

    I have hear of this but have not seen them... Has anyone come across fake components?

    what are the brands to watch out for ? what brands do you trust?

    I did see the vblog on EEVblog about a one time Mirco already programed with another projects program.. the chips where even placed on a reel.
     
  7. tom66

    Thread Starter Senior Member

    May 9, 2009
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    This could be cap plague, I'm not sure. There is no electrolyte leakage, just a bulging top.

    I think Intel once said the faulty caps may have had a "500 hour" lifespan. That's ridiculous. No component should behave that way.

    You're not being prejudiced. I think the problem is not corruption on merely China's part, but on appliance manufacturers and OEMs. (The PSU is an OEM job.) If they don't buy cheap parts, they won't get cheap parts! (Unless they are counterfeit, but that can be avoided through careful checks of the supply chain.) But, if they did that, their products would last longer than they wanted. Designed To Fail.
     
  8. tom66

    Thread Starter Senior Member

    May 9, 2009
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    They aren't fake - they're just crap to begin with. Like a (car example) Lada vs. a Ford or something. But, it would be fake if they did this, for example.
     
  9. debe

    Well-Known Member

    Sep 21, 2010
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    These are faulty caps in a13month old set top box for digital TV, so they are still coming out of China.
     
  10. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    I like Bunnies Blog. Wanna guess where I got the ESD picture in the ESD article? He has commented on other counterfeit stuff coming out of China. He does a lot of manufacturing there, so spends a lot of time in China (he's American). He had a problem with SD cards, so went looking on the black market for obvious counterfeits. Best case there was an illegal 3rd shift running the lines that made the quality parts, but a lot of tracking information was bogus (and had to be). Worst case was a SD case with no chip inside, just a chunk of copper. He was puzzled by this, as the copper wasn't cheap. Personally I think is one of our modern day geniuses making money. I loved his take on digital copyright standards (DMIC?), and how they are routinely misapplied. One of the cases he testified on was Sony objecting to an dude jail breaking his PS3, which Sony found objectionable and tried (unsuccessfully) to get the guy thrown in jail for a long time.
     
  11. nsaspook

    AAC Fanatic!

    Aug 27, 2009
    2,908
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    It's totally crazy what they try to get away with.
    [​IMG]

    [​IMG]
     
  12. tom66

    Thread Starter Senior Member

    May 9, 2009
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    The scariest part is the lower WV cap in the higher WV casing. So what happens when it is used in the mains primary side of a power supply? Who knows... could be deadly.

    Interesting to compare my power board:

    [​IMG]

    with someone else's, which has also failed:

    [​IMG]

    Notice the missing zener? That's for the overvoltage protection. In conjuction with the fuse. The fuse blows if the voltage exceeds the zener breakdown. Manufacturer cut out a <1 cent zener diode to reduce costs, but it also makes the board lethal to the controller board if the voltage goes too high.
     
  13. tom66

    Thread Starter Senior Member

    May 9, 2009
    2,613
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    It's fixed!

    I installed 6 new 470u caps in it. (United Chemi-Con low ESR.)

    I ignored the 220u for now. I'll fix it if it becomes a problem.

    Anyway for a total less than £3 I have a massive 18" beast of a monitor working. I'm very happy!
     
  14. tom66

    Thread Starter Senior Member

    May 9, 2009
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    Ah crud, it didn't last. It's not coming on again, or it switches off while running. It also makes a whining noise. I suspect the 220u will need replacing. So I guess I'll be doing that....
     
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