137 focus screen
Thank you all for the info,not sure where to go with this old girl now,had a quote a while ago to do seals,mirror cushion,new screen service and clean a trace of fungus out of the viewfinder that was £85+parts+carriage+vat the time the final bill totalled up I think I could source a nice secondhand RTS etc,trouble while very tatty it's working perfectly mechanically and optically,got to seriously think this through it's always operated in sub zero and extreme dessert temps in very arduous conditions so I have a soft spot for it! It's seen a few lenses come and go but is built like a brick,don't make them like this any more thats for sure,Anyway many thanks for all your help really appreciated.Andy