Help with my first Plasma TV repair on Panasonic TX-P42UT30B TV

[cheeky2]

Repaired quite a few LCD TVs however been given a Plasma to look at.
 When powered on the TV has only a green led showing on the unit!
 There is no other indicators ie flashing red leds on standby etc.
 The 5V standby is ok i have the service Manual however any help would be great!
 I have searched on the net without any success in finding a solution :(

 Thanks in advance :)