If the voltage never rises above the initial secondary rail, the backlight boost IC or its driving MOSFET is faulty. Technical Tips for Component Repairs
The following table summarizes common issues for the tp.ms6486t.pb753 chassis platform, based on real technician experiences: tp.ms6486t.pb753 schematic
DVB-T/T2/S/S2/C or ATSC (depending on regional SKU) If the voltage never rises above the initial