Pioneer PDP-LX5090 Kuro if hot & switched off,wont switch on again.

[bonesy]

Hi guy's,never repaired any Pioneer  Plasma's,this one belongs to a good friend .He tells me that the set switches on & works fine,but if switched off when hot,will not power back on. I've asked him to check for a blue light blink code,which will then give me a clue. I've read on the internet(I know,don't believe a word it say's) but there's more than one post about 8 flashes & a regulator on the AV signals board.Can anyone shed any light on this or is it rubbish?
Many thanks John.