LG 42PG3000 led goes green & back to red.

[tv john]

Hi guys  ,I have this plasma in for repair. At start up led turns green for a few seconds, relay clicks and then back to standby. The Va & Vs voltages rise with plug pl201 off on Y-SUS ,but both voltages fall rapidly and back to standby.
A post on another site mentioned the main pcb was to blame with a similar fault on a LG 50PG3000 model.
Aybody repaired  a 42PG3000 with these symptoms ?

Thanks John.