In the process of getting Dave Dunfield a door button for his Seimens 8 incher, I went through my whole stack of 8 inch drives and parts. I "found" a couple of SA-851s that, while the serial number plate says they are 115 volt, 60 Hz, are in fact built with the 50Hz drive pulley. You can put them next to a "normal" SA-851 and see that the pulley is a different size and I just confirmed it by putting a diskette in one, powering it up, putting a scope on the index signal and seeing that (on 60 Hz power) it is turning at 432 RPM a 20 percent increase over the 360 rpm it should be turning at. Other than that little problem, the drives seem to mostly function, that is, they seek, report track zero, etc. They appear to have seen very little use (probably because they don't fully work). Anyway, they weigh a ton (like most 8 inch drives) but is there anyone within reasonable shipping charges of Washington, DC that could use them and would want to work out a trade? Alternatively, it just occurred to me that maybe I could just exchange pulley wheels with someone? Bill S.