Internal speakers not working. Dell inspiron E1505 internal speakers are not working. I hear sound

Question

Dell inspiron E1505 internal speakers are not working. I hear sound when i use headphones. I checked all diagnostic test, reinstalled drivers, in vol control panel advanced settings its already sp mute button is unchecked. It was working fine till the day i was using laptop, TV and Iron box on single phase of 3 phase electricity. and it got trip ......since then not working