Kevin, I was thinking about your system this morning. It ocurred to me that if you have an H7861 power supply (it's rated +5V @ 36A and +12V @ 5A, BTW), you may have most of the rest of the box it was originally fitted in. That PSU belongs (belonged?) to a BA-11S box, which looks like a BA-11M box as used for an 11/03, but was actually made for the PDP-11/23-plus and the (OEM) 11/73S. The original box would have had an H9276 backplane, and an AC power input box as well. Now, if you have the H9276 backplane, you have no worries about putting a 22-bit system in it, because it's not only designed for 22-bit systems, but has on-board terminators. It's a straight QQ-CD 4 x 9 "straight" backplane; all the slots have Q22 in slots A/B and CD-interconnect in C/D. -- Pete Peter Turnbull Dept. of Computer Science University of York