Hello!
Perhaps you are right in that there are not supposed to be any L-shaped brackets for mounting the sheet-metal envelope. I got this suggestion from others as well.
The problem is that when I mounted it into the rack the holes (three by the way) didn't line up very well vertically with the rear rack post side holes.
Then the size of the screw is not the normal #10 pan head that DEC uses for most rack mounting. The nuts that are riveted into the envelope is #8 as far as I understand. The machine is 100km right now so I cannot check for sure, but looking at the picture and my remembrance of it gives that a #10 would not fit. It also has to a very short screw and perhaps a small shim in between the envelope and the rack post?
All this together made me think that there were to be brackets to hold the rear end of the envelope in place. Hence my question if anyone had one rack mounted already or perhaps know. The BA11-L manual doesn't give much information in this area.
However I did take another look at the drawing again and now I think I can see a screw in that area from the rear rack post into the envelope. It also mentions an item 54 (space enclosure) with a note #8 that says that there indeed is supposed to be a shim of some kind to handle the distance between the envelope and the rack post.
"8. Item #54 to be used A/R to take up any gap present between enclosure and cabinet uprights."
What is A/R?
Looking at the drawing it looks like that the screw head is on the inside of the envelope and that the nut is placed on the outer side of the rack post. But the drawing had perhaps not been updated for use of the riveted nuts?
I will make another try at this next time I get to my machines.