Other model numbers include LN40A550P3F and LN40A550P3FXZC.
Opening the back encountered 3 bulged caps on the power supply. I replaced 3 additional caps for good measure.
CM804, CM806 – 1000uF/25V
CM809, CM812 – 100uF/10V
CM810 – 470uF/10V
CM808 – 220uF/25V
CM813 – 47uF/50V not replaced, not bulged, didn’t have this value in stock
The TV powered up fine with the new capacitors.