Can you explain the problem in a bit more detail? However I'd imagine curved screens are always going to be tricky.
What motors are fitted? I've got Vetus Pantographs and they have been faultless in 5 years. If you replace I'd recommend these.
Thanks Adam, I think the problem is basically the motors fitted which I think are Spanish are just not up to the job and burn out very quickly I think because of the shape of the screen making movement difficult . Although this is contradicted by the fact that they tend to flop,off the screen very easily if hit by the slightest bit of water coming over the top. Space to fit is tight so I will be limited by replacement options. I wondered if it is possible to get ones with a longer shaft to offset the effect of the inclined screen.
Peter