how do i fix my subwoofer

wanky

Member
2008-01-03 12:01 pm
i bought a home speaker system second hand and it has really bad distortion throught the subwoofer channel, all the other speakers work fine. I opened it up and found 2 bulging and dried up capacitors with my ESR meter so I replaced them but the problem still remains. I dont know much about amps what else should i look for with this distortion .f rom what I see its using LM1875T amps for the speakers and using IRFP150 & IRFP9150 for the subwoofer, could these be stuffed? how do i test them?
thanks for help :D
 

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wanky

Member
2008-01-03 12:01 pm
i replaced the cap but no difference. i measures voltages of the mosfets while playing audio and they dont change at all

IRFP150 Vgs 3.2v Vds is 49.4v
IRFP9150 Vgs -2.9v Vds -48.9v

should the voltages be the same? also shouldnt gate voltage go higher than that? plz help im trying to learn