I have a NEC multisync LCD 1810X that I bought on Ebay. It has started to refuse to come on and only works internmittently after being turned on and off several times. I know its not the cable as the No signal message doesn't even appear. The Power LED comes on, but usually there is no light visible from the backlight which can be see through the slits in the casing. If turned off and on again it will sometimes work eventually, and then continues fine until I switch back on again the next day when nothing appears again. Any idea what might be the matter?