You will probably find that the main power supply board is failing, boards can be purchased of ebay for anywhere up to £120 which are refurbished, or cheaper ones from £40 up over, but be careful where you buy from, as off course you might be buying another board which has the same problem, check out sellers first, as this is a common fault, a repair kit can be bought from charles hyde and sons for these boards, for about £40, but this should only be done by a competent engineer, also if both lights stay green, and you still have sound, shows the media box is working ok, but if media box is showing red with no sound, the media box would probably just want the power supply resetting, to me though as your problem lies with the mainpower board, and not box or connecting lvds lead, this is a common problem on these sets, hope this helps,
idc1966, March 2010