lg 50pg6010 blanks screen

[bluesmoke]

hi  would some one be so kind to help me i have a lg 50pg6010 that powers up and you can hear a relay clicking  a few times on the main power board  but the set only powers up to a black screen with both back lights on but when the relay clicks the screen switches off then back to black it does this a few times before just staying on and black
im not really familar with plasma's so really need a nudge int he right direction if possible
i can't see any bulged caps and all fuses seem ok
im getting 5v and 3v at the control board i have tried unplugging the ysus board but the set just displayed the red standby light any help would be great thanks dave