Samsung 22 inch lcd tv problem after some time white display

Samsung 22 inch lcd tv model no la22b450c8 problem after some time white display 

Follow this step

  1. In this case first i will check panel voltage are coming are not .if panel voltage is not come then also white display are coming 
  2. If panel voltage ok then next step to check vgh ,vgl ,avdd,v com,etc . this voltage are not present then also white display is come . in this case this all voltage is coming but after some time it goes down 
  3. If all voltage are coming and goes down then check sorting on source PCB .In this case i will check but no any sorting is found on source PCB .
  4. Then next step to replace dc to dc ic . in this source PCB two five lag is is present which is responsible vgh ,vgl ,avdd,v com 
  5. Then i replace this two ic after replace my set is runing fine
  6. Image of this ic shown n fig.