I copied this out of MMM and posted it on another site as someone was having problems with blinds sticking and were going to tighten the tensioners, this cured it.
It is usually grime that has built up and not the tensioners. Do not use WD40 as it may mark the blinds. Rather than dismantling , as a first step try cleaning the guide rails and the plastic bearings supporting the roller, if you can reach them. They say ordinary household detergent (not washing up liquid) in a finger spray and an assortment of cheap artist brushes and old toothbrushes. If that does not work an aerosol solvent such as switch cleaner, or even clutch and brake cleaner fluid can be tried, but check on a small hidden area first.
After cleaning allow things to dry for a day or two and then lubricate with a suitable clear silicone lubricant such as Thetfords cassette toilet blade spray.
If cleaning has not effected a cure, retensioning the spring may be required.
It is usually grime that has built up and not the tensioners. Do not use WD40 as it may mark the blinds. Rather than dismantling , as a first step try cleaning the guide rails and the plastic bearings supporting the roller, if you can reach them. They say ordinary household detergent (not washing up liquid) in a finger spray and an assortment of cheap artist brushes and old toothbrushes. If that does not work an aerosol solvent such as switch cleaner, or even clutch and brake cleaner fluid can be tried, but check on a small hidden area first.
After cleaning allow things to dry for a day or two and then lubricate with a suitable clear silicone lubricant such as Thetfords cassette toilet blade spray.
If cleaning has not effected a cure, retensioning the spring may be required.
