Electrolytic Capacitor Have The Highest Failure Rate
I have replaced more electrolytic capacitors than any other electronic components in electronic repair. The reason why it has the highest failure rate was because electrolytic capacitors contains electrolyte (one kind of chemical) and this electrolyte can dry up and will leak when it is overheated by higher voltage than the capacitor itself can handle. Resistors do not have life span not like electrolytic capacitors. E-caps got to be use fresh once they are out from the factory! If you keep the e-cap for too long, the electrolyte in it will dry up and cause many troubles in electronic circuits.
It is wise to invest on ESR meter which can test e-caps in or off board. Although some e-caps shows leaking underneath, the esr meter may still test good on such capacitor. This is because the leaking of electrolyte haven’t reach to a level where the ESR meter considered it as bad cap. The more you use ESR meter the more you would understand its capacibilities. If you haven’t buy any of the esr meter, you may get one by clicking here.