KDJ11-B in a PDP-11/23 backplane?

[Patrick Finnegan]

David Betz declared on Thursday 16 September 2004 02:20 pm:
> Thanks for your response. Both of the backplanes you mention seem to
> be 8 slot backpanes. The box I have only looks like it has space for a
> 4 slot backplane like the H9270. Is there a four slot backplane with a
> Q22/CD slot?

Assuming you don't want to use PMI memory with the KDJ11, you could 
probably just remove (unsolder) the right half of the CPU slot, and 
solder some bus grant jumper wires on the back.  You can determine what 
lines need to be jumpered from an M9047, and it shouldn't take too much 
work with a dremel tool and soldering iron to remove the right half (two 
connectors) of the CPU slot.  This is, of course, assuming you're 
comforatable doing that.  If not, you can either get something with a 
4x8/4x9 Q22/CD backplane, or perhaps a 2x4 backplane (H9281-BA/QA).  The 
H9281-BA will need you to connect A18-A21 (top 4 address lines) through 
to each slot, as it's only Q18.  The H9281-QA should work unmodified.

However, I think it'll be hard to find any useful backplane, you'll 
probably either want to try to get something like a BA23, or modify the 
backplane you have.

Pat
-- 
Purdue University ITAP/RCS        --- http://www.itap.purdue.edu/rcs/
The Computer Refuge               --- http://computer-refuge.org