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

[bluesmoke]

hi sorry to be a pain but has any one any tips on this problem just a black lit up screen .
or ideas on the best way to fault find which board is at fault as all boards seem expensive so dont want to buy the wrong one and i dont trust some of the smashed screen sets on ebay as i have been conned before

[fix2003]

Check All outputs from the power board are correct VA, VS, 12V 5V 16,5V 9V M5V.
Are the Heatsinks on YSUS and ZSUS  cold ??
Check  fuses on each panel