This is only a preview of the March 1993 issue of Silicon Chip. You can view 44 of the 96 pages in the full issue, including the advertisments. For full access, purchase the issue for $10.00 or subscribe for access to the latest issues. Items relevant to "Low-Cost Audio Mixer For Camcorders":
Items relevant to "Test Yourself On The Reaction Trainer":
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Publisher & Editor-in-Chief
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ISSN 1030-2662
2
SILICON CHIP
Computer monitor reliability leaves
a lot to he desired
Over the last 20 years or so, the reliability of consumer electronics appliances has become almost legendary. As a result, many TV servicemen have
either retired or gone out of business. But there is one area where the overall
reliability leaves a great deal to be desired and this is in regard to video
monitors for personal computers.
While you would think that the enormous complexity of the new motherboards
or hard disc drives would make them suspect, it is the computer monitor
which, more often than not, is the first item to fail. This is despite the fact that
computer monitors are much simpler than the average colour TV set and the
· deflection circuitry is probably not working as hard. Yet computer monitors fail
often, usually in the power supply or deflection circuitry- actually there is not
much else to fail.
This is not a new phenomenon by any means and in the days when
monochrome monitors were standard, it was usually cheaper and much more
convenient to buy a new monitor than to repair a failed unit.
These days though, VGA and large screen monitors cannot be simply
discarded when they fail;. they must be repaired. When that time arrives, be
prepared for a large bill. Many authorised service centres only do board
exchange and the cost can range from a few hundred dollars to six hundred or
more. Even though the fault may be relatively simple to fix, the companies
concerned often have a deliberate policy of doing board-level repairs only and
the consumer really does pay through the nose. In one very well-known brand,
a resistor in the starting circuit of a monitor's switchmode power supply
regularly fails. The obvious and easy cure is to replace that resistor with one of
a higher rating and yet the company concerned has never made any move to
change it. In effect, you pay over $200 for a burnt out five-cent resistor.
The situation is made even more difficult because computer monitors are not
supplied with a circuit diagram and they always use Japanese or Asian parts
which are often difficult to_obtain. Nor will most importers even deign to sell a
service manual or circuit diagram. And if the company concerned goes out of
business you are really on your own.
It would be easy to conclude that there is a certain amount of unfair trading
going on in this field. That means that consumers should try to at least obtain
a circuit and preferably a service manual when they purchase their monitor. I
say that, knowing just how difficult it is in practice. It also leaves the way open
for importers to establish a more enlightened policy on this often unhappy
aspect of computing - their customers will love them for it.
Leo Simpson
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