I collected a dvd no power from a friend, and checked it i discovered that its fuse and bridge rectifier are blown also d capacitor swell up when i change all these components and i switched it on it blow another ic, the 3 by 4 ic so i changed it and changed the str w6053 ic too.
Then i use bulb test in other to avoid components being damaged again, so when i switched it on the bulb the not light on but the power pack is giving a huming like hissing noise i checked the output voltage but no voltage. Pls what can be the causes of the noise?, the noise is around the switch mode transformer. The dvd home theater is LG model no: HT357SD.
Try remove the ac cable and discharge the big filter cap then quickly touch on the power section to see which component is the hottest. The hottest one is the cause of the problem. If there is no hot component probably you may have to check all the components in the power side. If all checked to be good then put in a new power IC and retest.