LG TV has sound but no backlight, power supply or bad Led's. How to troubleshoot

This 60 inch LG led tv has a defect of sound but no Picture. The model on this LG television is 60lb6300. The tv comes on with no Backlight but still has sound, or the backlight may even be flashing. Im going to troubleshoot and repair this set using my multimeter to check the LED+ voltage on the power supply board. LG 60LB6300 power supply board EAY63072201: https://www.ebay.com/itm/LG-60-60LB63... Please support are online store: https://bigdogelectronics.net/