dimanche 7 mars 2010

Using Dick Smith Esr Capacitor Tester

Using Dick Smith Esr Capacitor Tester or Meter to Check Ceramic and Non-Polarity Capacitors On Board

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A Dick Smith ESR Meter

The dick smith esr capacitor tester or meter besides can be used to check electrolytic capacitor, it can also measure the non-polarity one such as the Ceramic, Mylar, Film and so on. It is not mentioned in the meter’s manual that it can test the non-polarity caps. In fact this esr meter is specifically designed to check bad electrolytic capacitor only.

When I began to do some experiment with the Dick Smith esr capacitor tester i found that it have the capabilities to check the non-polarity cap as well. There’s only one disadvantage in testing the non-polar caps, where it can’t test non polarity capacitor in the lower capacitance value.

Any capacitance value lower then .1 microfarad (104), the meter will not show esr reading. This is due to that the dick smith esr meter can only read esr values until 99 ohms. Perhaps others high end ESR meter such as the B & K and Sencore lc103 capacitor tester have the special range to test it. You will even be surprised too to discover that the dick smith esr meter can test the non-polarity capacitor on board (in-circuit without taking out the capacitor from the board).
There was a Philips 17” Computer Monitor send for repair with the complaint of top part of the display jump horizontally. You could notice a bunch of horizontal black lines that appeared across the top display. Since the fault was jumping horizontally, so the caused of the problem would be in the vertical section.

The weird part was that there were no components found faulty in this section. The supply voltage, vertical output and oscillator ic and all surrounding components checked to be okay. Even the vertical yoke coil also in good condition. So where was the fault? For your information I used digital capacitance meter to check the non-polarity caps and esr meter to check the electrolytic capacitors.

The display jumping still looks very obvious and I’m almost giving up on this repair because it took me lots of my time. Every track and every component I have checked to be working fine and I’m still wondering why I still could not locate the culprit in this little section of vertical part.


I made my last attempt to tackle this problem by using the Dick Smith ESR Meters. I compared all the non-polarity capacitor esr value located surrounding the vertical output or driver ic. Finally I found a capacitor with the esr value very high. The normal value for a .22 microfarad non-polarity cap is between 6.5 to 7 esr ohm but the defective one have a value of 14 ohms! It is almost double in the esr value but the capacitance tested okay with a digital capacitance meter.

Because of out of normal esr ranges, the display jump. The good news is I discovered the bad capacitor while checking it on board. If you are a beginner, I strongly suggest that you remove one leg of the capacitor and test it. Once you have mastered the art of using the meter, you can begin to test non-polarity capacitor on board. Changing the faulty cap with a new one solved the display jumping problem.

Not long ago, a repair friend of mine sends me an Oven circuit board. Upon checking the esr value of the non-polarity capacitors, I found a capacitor esr value totally out. The value has gone too high and caused the board to stop working. The normal value of the capacitance is 824 (.82 microfarad) with a low 1.6 esr ohms, but the faulty one read 23 ohms esr value! Replacing the capacitor solved the problem.

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A good .82 microfarad ESR reading




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A Bad ESR Reading


If you really want to accurately test a non-polarity capacitor, besides measuring the capacitance value with a digital capacitance meter or using analogue multimeter to measure the charge and discharge function, I recommend also that you check it with a esr capacitor tester or meter as well. If you missed one capacitor (which is suppose to be faulty and you think it is good), the rest of your troubleshooting time is just a waste. Hope this article will inspire you to get a esr capacitor tester or meter to include to your range of troubleshooting tools. Happy repairing!