no backlight for lcd?

Hi

Been having issues with the lcd not working after a replacement (it did work for a couple of days)

So put another lcd in and still no joy? It does sometimes fire up when the board is lifted up and all held in place by hand.

However, while looking again, the sun was shining right on the screen and a could just about see all the text etc. So I'm now wondering why the backlight isn't working?

I have bought another lcd main flex cable. As sometimes it has fired up, so can't really be anything blown???

does anyone know what else I can test on the board?

Thanks