PDP 11/24 Wierd Unibus Setup

I've pretty much got this PDP-11/24 up and running, except for one confusing detail. There are some (what I consider to be) strange cards plugged into one section of the unibus. In this box, there are three seperate sections of bus. The one on the right has 9 slots, and contains the cpu, memory, dl-11, etc. The one on the left has 4 slots and contains the bus terminator, as well as the controller for the RA-80. It is joined to the right hand bus by an extension cable. The middle section of bus is the wierd one. It contains some kind of power supply cable and a bunch of single-height flip-chips. Here is the setup: 1 2 3 4 A Power B M205 M660 C M116 D M113 E M112 F Anyone have any ideas what this is for? Thanks.