Page 104 - Testing Electronic Components

substitute all the suspected parts one by one and replaced with a good
working component.

I eventually found the caused of the power supply problem. Guess what?
It was the main power filter capacitor problems (220 microfarad 400
working voltage). After replacing the filter capacitor the fuse would not
blow when switch on and the power supply worked perfectly fine. I begin
my detective work to explore why this particular capacitor can caused the
fuse to blow even though the filter capacitor already confirmed working
with all my faithful meters.

The meters that I used to test the filter capacitor were analogue
multimeter, digital capacitance meter and the famous ESR meter. I
assumed that many of you who read this book already know how to
perform capacitor measurement with all the meters I’ve just explained in
previous section.

Using an analogue meter to measure this filter capacitor showed capacitor
is charging and discharging (meaning the pointer will flick up and then
gradually goes down), test with a digital capacitance meter showed
around 220 microfarad (still within the capacitor tolerance range) and
with the most powerful electrolytic capacitor tester which is the ESR
meter, it showed a low ESR reading which is also a good reading! Then,
how do I know if the filter capacitor is faulty since all the meters tested
ok on the filter capacitor?

What I’ve checked on the filter capacitor is just the value, ESR and the
charging and discharging test but another test you should not miss out
which is the capacitor dielectric or leakage test. Use this test only when
you want to check capacitors that have working voltage exceeding 250
volt. By using an analogue insulation meter you will be able to test the
capacitor leakage.

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