Reading capacitance on SM capacitor

Jun 16, 2005 3 Replies
N

Hi,



I'm looking at a laptop (Toshiba Sat 3000, to be specific) motherboard that having some SMD suspecting leaky capacitors; Some basic questions if someone can bring me up-to-date to the world of surface mount device, that would be nice:


  • There are four of them in parallel; ohm reading both way, in circuit, about 50 Ohm. They are around the power charging area, and the circuit having a blown fuse. Would this sound like a strong posibilty for leaky cap ? (I can take them out one by one for sure...)


  • The capacitors are the good size ones in the SMD world (6mmx4mmx3mm); There is + sign printed on one end, and the printed note say "220" on first line and "g14" the next line. Would that be 220 pF ? Seem little for that size...



Thanks for any advice.



Cheers,



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R

The best trick to use is heat one let of the capacitor in question, & smell for a "fishy" smell. Rono.

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E

The caps may or may not be shorted or leaky..... you should remove one leg so you can test them out of circuit. 220 MFd or 220 uF..... not

220pF electricitym
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J

The capacitors must be removed to properly test them. Most likely there are other components connected the capacitors, that are giving you the resistance reading. Caps should be tested with both an ESR meter, and a capacitance meter to truly have an idea of their performance.

Jerry G. ======

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