11/73 into 11/03 chassis?

I'm not absolutely sure exactly what you have that's holding the '11/03 backplane'; if it's a standard BA11-M enclosure, the answer, sadly, is 'no'. The BA-23 uses the H9278-A backplane and H7864 power supply; the BA11-M uses the H9270-A and H780 backplane. The power connections between the first two are completely different from the latter pair; the first uses a long, single-width Molex-type connector, the latter uses bare wire ends to a terminal block on the backplane. Also, the H9270-A is a four-slot backplane, and the H9278-A (an eight-slot) almost certainly will not physically fit into the space for the former. If your '11/03 backplane' is a different kind of backplane, in some other kind of box (e.g. BA11-N or BA11-S), the answer, sadly, is still 'no', because they both also use terminal blocks for power. (Although if you have a BA11-S, you'd already be set, those are Q22 native.) Really, it's not that hard to upgrade an H9270-A (or the H9273-A in a BA11-N) to Q22 (I have done several of the latter); the transplant you speak of (were it possible) is on the same order of magnitude of work. Noel PS: In dragging my BA23 out to look at it, it dawned on me that I will probably never, ever use it - I now have several BA11-N/S boxes, and prefer them. (I don't need to run the later disks that need the BA23.) So if someone is interested in the either the BA23, or the spare H7864 I have for it, please let me know. I'll let either go for my original cost plus shipping.