intermitant samsung fault?

we can switch samsung lcd tele on but occasionally screen goes black but you can hear sound. tv is connected to sky. from what I can gather this is a fairly common fault so I guess my question is it a fault that I can sort or does it need to go to a repairer Allso does any one have any idea the repair should cost. Know that a bit like how long is piece of string but be nice to know price of part and general labour costs so can have rough idea not getting overcharged THANKS