My SMBS (ATX) is damaged, please help me

I've an smbs it is not working now.. i don't know what 've happened.. please help me few necessary thing i've to give kind attention for repairing smbs. Can u suggest me what are the recent problems occurring in SMBS. What are the method to trouble shoot it.

please help me

I would suggest that you either purchase a new SMPS in lieu of trying to replace the defective one. They are too complex for the most part for beginner techs to be servicing. If you don't repair it properly, it could ruin your entire PC. For what a new supply costs these days, it's good insurance to just buy a new one. You can also check with a computer repair shop that may have used, good working units available at a reduced cost.