403? Is that a VisionMaster 17" by any chance? If so then yeah, that's exactly the same monitor model I had all the trouble with. The monitor is at my mum's house now so I can't actually check what model it was.

The first one I had was the dud pixel one. Then I had one that refused to show anything in text mode. I think the next was the one that would suddenly go all purple and cut out until it had a chance to cool down. The one after that had issues with warming up as the picture size would increase by about 5cm from cold.

It was the gall of the engineer that got to me. The engineer was pretty much accusing me of not knowing how to plug the monitor in and how they would test fine on his test bench which meant I was lying etc... Needless to say, I've never bought any of their quality products since.