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