I have a Sigma floppy disk controller which I believe to be for Qbus. The assembly number is 400255 rev B and S/N is 4331. It is a dual board and has a pair of 2901 bit slices and an assortment of bipolar PROMs. From the field guide, I found this entry: SDC-RXV31 Q Sigma floppy disk controller. Emulates RXV21/RX02. (Supports Mitsubishi M2696-63) I assume this is the one. Does anyone have a manual for this controller (copy or scan)? --tnx --tom