Maybe you have encounter power problem where once you activate the energy supply and the fuse blow? You've checked most of the components in the energy (primary) and secondary section and most of the components appears to be ok! Where's the fault? A fuse blown are generally caused by a shorted bridge rectifier, defective posistor, power transistor or FET, shorted primary winding of switch mode power transformer, shorted secondary diode and etc. But in this article I'm gone to show you another secret of electronic troubleshooting tips.
I acquired frustrated regarding where is the reason for power problem. Everytime when i activate the energy supply the fuse blow immediately (the fuse became dark color and this indicate that there surely is an important short circuit in the energy supply). I've checked most of the components in the energy supply and can't find to blame! What i really do is i desoldered most of the suspected parts 1 by 1 and replaced with a known good component. I eventually found the caused of the energy supply problem. Do you know what? It had been the main filter capacitor (220 microfarad 400 volt). After replacing the filter cap the energy supply worked perfectly fine. I begin my detective work to discover why this capacitor can caused the fuse to blow although i already confirmed it OK with my meters.
The meters that i used to check on the filter cap were analog meter, digital capacitance meter and esr meter. In this article i won't explain about how exactly to check on capacitor or testing capacitor and how capacitor work. I believed nearly all of you understand how to check capacitors and also generally using this sort of meters. Measured with analog it showed capacitor charging and discharge, with digital capacitor tester it showed around 220 microfarad and with esr meter it showed low esr reading!
This proved that the bad capacitor breakdown when under full operating voltage. Then, how do you confirm this filter capacitor is faulty? By utilizing an analog insulation tester. When i connect the faulty cap to the meter and press the go button-it showed a very low resistance and this is the proved of short circuit between the plate when voltage applied! There's nothing regarding bad electrolyte. A good capacitor will just showed a demand and discharge in the insulation meter like everyone else are checking a capacitor using analog multimeter. Available in the market there is quite several ranges that you can buy. It has the range of 50v, 100v, 250v, 500v, 1000v and even 5000v! If you intend to test a capacitor of 100 microfarad 160v then you definitely have to select 100v. If you choose 250v, it will blow your capacitor that's under test.
If you have the SENCORE TEST EQUIPMENT such as the sencore lc meter LC102 OR LC103, these meters have the capabilities of checking almost any capacitors with four tests:
-testing for capacitor values
-checking for leakage
-equivalent series resistance (ESR) and
-Dielectric absorption
It may check aluminum electrolytic capacitor, film capacitor, ceramic, high voltage capacitor and etc.
Conclusion-Different high voltage diode manufacturer produced different kind of quality of a capacitor. Possibly the bad capacitor that I encountered are from the lowest grade one. A capacitor failure when under load is extremely rare. Using ESR capacitor meter alone can solve most of the electrolytic capacitor problem.
