
simone wrote:i have one question: the rubber band is stiff without breaks (is the original and i want to preserve it) so i would ask if you know a tip to soften this?Please let me know....
There's unfortunately not much you can do, as the flexibiliser has evaporated. For old computer equipment I use Ballistol Oil or (in case that doesn't help) Glycerine -- but that's only a temporary relief. There's no way to get the flexibiliser back into the rubber. If it's gone, the only thing that helps for sure is replacing the faulty part.
Did you consider buying a replacement strap for the F91? It's not exactly the same, but maybe close enough. I'm not sure though if the lug spacing is the same. If it's the same, I would just buy a whole F91. It should cost no more than 20 Euro and who knows? Maybe it will be a "classic" in 20 years
