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Dave Rants &
Raves |
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Bad Chinese
Capacitors
I’m seeing a
disturbing trend. For several years now I have seen many expensive electronic
products die an early death due to poorly constructed electrolytic capacitors.
Nearly all of these bad devices are made in China. Just last year I lost an
expensive 1 year old HP printer due to a bad capacitor. I traced the failure down to
one bad capacitor, which failed shorted. That shorted part killed a number of other
parts. So many parts were killed that repairing the printer was not practical.
A printer should last a lot longer than 1 year. |
| I’m now reading
that other people are seeing more and more of these vital components failing. Some
leak corrosive fluid. Some have budging cases and still others have actually burst
open. Electrolytic capacitors have been around for
some 100 years. They are found in almost every electronic product made. Their
100 year history has given manufactures plenty of time to get the process down to fine
art. In my early engineering life, seldom did these parts fail. I have owned
many TVs and radios which have continued working well past some 30 years. Now, it
seems that many products fail from defective capacitors in a very short period of time.
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The illustration below shows how the
classic electrolytic capacitor is made. Two aluminum foils are separated by a
paper spacer impregnated with a semi-liquid electrolytic material. The liquid
maintains an aluminum oxide insulator surface on the foils. The assembly is
rolled up like a jelly roll and pushed into an aluminum can. Rubber and plastic
seals the assembly. The oxide layer dramatically increases the surface area
between the two metal plates, which allows these devices to offer a sizeable amount of
capacitance in a small package.
Now, as some of the photos below illustrate, there
has been a rash of bad capacitors in expensive new electronic devices.
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| The Chinese seem to be
cutting corners and we all suffering from it. In another example below, they
have also been inserting smaller value capacitors inside larger aluminum cases.
This part will most likely fail in short order. |
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| Capacitor cover pealing
away |
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Bulging and leaking
capacitor |
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| Leaking Capacitors |
Leaking Capacitors |
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| Split-Open Capacitors |
Fake Chinese Capacitors |
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