Rumba board

Guys

I have a rumba board with a problem

I though it had a faulty USB port but I replaced this with no effect

When I plug into laptop the power light flashes for a split second, that's all. Sometimes (possibly once in 100 tries) the laptop detects the board but again only for a split second.

I have swapped jumpers etc for USB power.

Anyone have any ideas or an up to date schematic?

My board is the one with the reset button behind the USB port

Thanks