My 9133, which originated this thread, is a 9133D, with a single controllerboard, one DS floppy and a ST419 15MB MFM disk, a disk which is clearly older than the ST225 ( it is similar in construction to a ST506 or ST412) First problem with the drive turned out to be severe head stiction. It is spinning now, so I might yet be able to coerce some life out of it. Jos