Daewoo DT42-AI sound, no picture

[bobbuild]

Just after advice. We are a hotel and have 6 of these Daewoo tv's. Two of them have now suffered the same problem. Tv switches on sound is ok but totally dead screen. One is away being fixed, apparently it needs a "Sus board kit" needless to say this is costing an arm and a leg and is taking forever to arrive. I am assuming the second tv has the same problem. Is this a "known" fault with these sets in which case presumably the other 4 will go down eventually (they were all bought at the same time), and if so is there any point tackling Daewoo about it? The tvs are only just 2 years old!