Generally, equipment made in Taiwan (electronic or machine types) are much
better quality than similar equipment made in China, IMO.
There are likely to be instances of circuit boards manufactured in China,
which are then assembled into a finished product elsewhere (Taiwan, USA or
other) which are no better than the Chinese equivalents though.
IMO, the only difference between a good and bad poduct, is if the
manufacturer designs and produces with a conscience.. not many operate in
this way, with very little or no quality control built into their production
facilities.

Looking at capacitor manufacturers' specifications will generally indicate
why even good quality capacitors fail. The bottom line is that the caps
aren't rated to meet aerospace or military ratings. Most quality
electrolytics have a rating of 2000 hours when properly placed on a board,
not beside a 5W power resistor in a heated area with very poor ventilation.
Equipment and even individual component design specs don't include
manufacturing defects or design changes, and most every product made today
has an attached disclaimer of: specifications subject to change without
notice.

When discount store consumer equipment lasts more than 2 years, that's about
the best that can be expected, depending upon the type/level of usage and/or
abuse.
For service that would be comparable to commercial use, one should buy
better equipment than the retail stores have to offer, or expect to pay the
equivalent cost of high grade equipment, by replacing cheaper equipment.
I know there are many exceptions that have lasted far longer than 2 years,
but they were typically made when manufacturing standards were higher than
today.

A better time to evaluate/examine equipment internally, would be before it's
put into service, instead of when it quits working.
If the internal design looks badly done, put the device at an unimportant
station, give it away to a employee (or raffle), or just sell it.
There are businesses that can provide testing and failure analysis for
electronic equipment.

Making equipment more compact leaves little space for airflow and/or heat
dissipation. Power supplies used to be separated from most of the signal
sections.
In new equipment, about the only time bare board is seen is when it's in the
lower priced version of that particular model, with less features, so some
components have been omitted.
I looked at a Acer 15.5" PC LCD monitor at a store yesterday that was about
as thick as 2 or 3 common paper tablets, and the PSU was internal.

As mentioned before, from a repair/servicing standpoint, one should only buy
quality components from a distributor that maintains a fresh inventory
direct from the manufacturer.
Not buying replacement caps in great quantities which will just sit in a
drawer for a year, should ensure that they won't start to develop faults
before they're installed.
Old stock electrolytics are likely to be inferior products. Many quality
brands of electrolytics are marked with date codes.

I've wonder how many technicians actually test new electrolytics before
installing them. Excessive internal leakage, for example, is as serious a
fault as high ESR.

--
Cheers,
WB
..............


"D Yuniskis" wrote in message
...
Hi,

[Apologies if this appears as a repost -- it hasn't
shown up on my server in the better part of a day]

I've been repairing lots of "defective" LCD monitors
for a local non-profit. Of course, many boil down to
bad electrolytics from those notorious Taiwanese
manufacturers.

[I'd like to avoid rehashing that subject as I am sure
there's nothing *new* that anyone can add -- and, it's
not the nature of my question, here!]

What I would like to know is which circuit topologies
tend to aggravate this problem. From my casual
observations (I've done most of my repairs without
the benefit of any design documentation), the failing
components either seem to be proximate to heat sources
*or* in configurations where they see high ripple
currents (suggesting this is a problem with the
devices' ESR -- internal heating).

My observations come from a few *hundred* samples
from different manufacturers, different models,
different subassembly manufacturers, etc.

Does anyone have any *definitive* answers about this?
And, long-term remedies? (i.e., does replacement with
a good, high temp, low ESR cap *solve* the problem or
just kick it down the road?)

Are there lessons to be learned when *designing* these
types of circuit topologies to avoid these failure
modes? (besides picking good vendors)