Does anyone use the Metered prism for the Pentacon SIX TL and could possible give some advice please?? I've recently obtained one but seem to be unable to get the meter to work correctly even though it is supposedly in full working order. Before I shout at the dealer (who unfortunately is overseas), some advice may be in order. It did initially appear to work but the readings were out - now it seems to stay at the same point whatever apperture/speed I set it at.

I have the original plain focusing screen on the camera - there is a suggestion on the online manual I saw for the prism that it won't work with this, is this likely to be the case? Also, this prism has rattled ever since I removed it from the box - seems to be somewhere around where the top left-hand corner (underneath where you check the meter), I suspect it shouldn't do this?? I've also read that its necessary to put the cap back on the viewfinder eyepiece when using the meter to avoid incidental light, is this correct? Any help appreciated before I through it out of the window!