LG 42" LCD wierd picture

[stuhar]

Hi all I have a Lg 42 lcd that has got blank parts on both sides of the screen when first powered on but after 5 mins it goes ok but is leaving gosting from menu or previous channels until after about 10  to 15 mins then all is ok I have changed the lvds board and still the same all the backlights seam to be lit is there anything else appart from the mainboard that could be the culprit this tv is a labeled Vistron but all part are LG inside is maybe the power supply faulty untill warmed up! all caps look ok no bulging! the part I changed was LG 42LF65 - LVDS - 6870C-0146A - A-1-4 - 6871L-1136A - LC420WU2-SLB1 thanks all