ESR Meter- The Capabilities To Check Beyond Electrolytic
Capacitor
There is something good about esr meter because besides
electrolytic capacitor it can be use to measure other type of
capacitors such as the non polarity capacitor. From esr meter
specification, it is usually mentioned only checking the
electrolytic type. When i began to experiment with the Dick
Smith ESR Meter i found that it have the capabilities to check
other type of capacitors as well.
However it is limited to checking capacitor in the higher value
only such as .1uf(104), .22uf(224), 1uf(105) and etc. Lower
capacitance value don't get any reading from the esr meter due
to it can only read until 99 ohms. Perhaps other esr meter such
as the B & K esr meter have the range to check it.
You will even be surprised to see that the dick smith esr meter
can check the non-polarity capacitor in-circuit (without
removing the cap).
True case example-Monitor came in with display jumping
horizontally. You can see a bunch of horizontal black lines
across the top display (picture). From experienced it will tell
you that vertical section have problem. I begin to troubleshoot
the vertical section. Supply voltage checked ok, vertical driver
and oscillator IC replaced, all components connected or nearby
vertical driver and oscillator ic have been checked ok. By the
way I used digital capacitance meter to check the non-polarity
cap and esr meter to check the electrolytic cap. The problem is
still there and can't be solve!
When i use Dick Smith ESR Meter to compare the esr value of a
non-polarity capacitor located near the vertical driver ic, i
noticed that there is a big different in the esr value. The good
esr value for a .22uf non-polarity cap is between 6.5 to 7 ohm
but the spoilt one have a value of 14 ohm! Almost double the
value, that's why the display jump. The good thing is i
discovered the culprit while the capacitor still in the circuit
which mean this esr meter can check non-polarity cap in-circuit.
However my recommendation for you is to solder out one leg and
check unless you already have the experienced in checking
components on board. Replacing the cap solved the display
problem.
Conclusion-In order to accurately test a non-polarity capacitor,
besides checking the capacitance value and using analog meter to
check the charge and discharge to see if it has develop any
short circuit when under load, you are also required to check
the esr value as well.