it's working but something happened inside like this~what's that??

wow!!!

help me out~~~

Looks like an electrolytic capacitor has blown it's top!

The question is why?

it happened b4 i got it
but i dun know will it affect anything

Looks like the caps are dry after all these years.
Just replace them all

henry
those caps appear to be nothing more than "snubber" capacitors in the ac supply. just clip them out of the circuit and leave them out. they are not necessary at all.
good luck with it
danny