Looks like the root cause was a loose cnnector behind the screen. This looks like poor design as there is nothing retaining it. Anyhow in the mean time the screen itself has developed a fault so I am looking at swapping it out. The one in there is a B140RW02 AUO (40-pin connector), does anyone know ...

Last time I looked, zero ohms is continuity. You weren't thinking "infinite ohms" were you?

D'oh! These 0402 components are ridiculous (and I work with them professionally too.) F3 and F19 are both OK - read 0 ohms. Given that there's an F19 one question is where are F1, F2, F4-6, F8-F18? Anyhow the hunt is still on for the fault. Is the boost convertor for the backlight on the motherboard?

Thanks first time I've seen F3 mentioned, previously it was F7 (which is OK)/.

F3 is indeed open circuit and it's on the top of the board so no need for much disassembly, if you can get the iron tip in there.

Thanks again.

What about this "LED Board"? I have a T430 with no backlight (you can see the dim logo on the screen). I found a LED board on ebay (e.g. part number 94V-0 CN0404) but it doesn't look man enough to be a DC-DC convertor (i.e. drive the backlight)? It only seems to have a few resistors, caps, diodes an...