Philips TV sound but no picture

Trying to diagnose an issue with my Philips Ambilight TV (50PFT6510) that has recently decided not to display anything at all but I can hear sound and see the ambilights change etc.

I have tried both HDMI ports and the antenna input from a few different sources (Laptop, Virgin media Tivo box etc), as well as having tried a few different HDMI cables. All to no avail and the TV still only plays sound but no image.

I have checked the power board and main board over for any blown capacitors but can’t see anything obvious. I have also replaced the TCON board and re-seated any ribbon cables to and from this board.

Before this blank screen issue, we did have a dark strip on the TV that which indicated a row of LED’s on the backlight was not functioning. At this point, i’m trying to work out if its worth diving deeper and spending some money on a replacement main board or just get a new TV???

If anyone has any suggestions, can see anything else I may have overlooked or has a pretty solid idea of what it might be i’d love to know.

Thanks in advance,

Rich