Yes, it is as you describe, several horizontally
rackmounted backplanes
with a dedicated PSU. I have a FS printset and a user manual.
Some pictures can be seen at
http://tinyurl.com/5w4l6uv
It l;ooks a lot like mine, but, of course ,it could have different
flip-chip cards or differnt wiring. I am _sure_ mine is a DX11
My lamp panel has LEDs like yours, it also has a panel over it to label
them. They basically show the values in the unibus-accessible registers.
You can use the same type of lamp panel with the RK11-C cotnroller
(obviosuly with differnet lablellign). I should move the panel from one
of my DX11s to my RK11-C (which get s a lot more use :-))
-tony