Backplane
The first item I purchased was an H9270 backplane and card cage combo. The unit started out life in 1981 as an H9270-A Q18 backplane in a BA11-ME PDP-11/03 expansion enclosure. At some point afterward, it was modified and turned into a Q22 backplane, apparently as a part of a processor upgrade to a PDP-11/23. It came with a cable guide, which will prove useful for protecting the wire wrap posts and it allows cables to be lashed to the back.
When I received the backplane, it was dirty and a little dinged up. The first thing I did was completely disassemble it and wash the backplane with contact cleaner. The card cage and related pieces has some of the dirt knocked off with fine steel wool, then a wash in warm soapy water. After everything was dry, I straightened the card cage and re-assembled the unit.
Before cleaning and repair:
Backplane after cleaning, installing the card guides and straightening the wire wrap posts. Most of the wire wrap work is the Q18 to Q22 modification. The rest is extending the SRUN signal from slot 1 to the front panel header, located in the upper left portion of the circuit board, above 1D.
Note that I later re-wrapped the backplane, becuase the pattern used would have resulted in termination issues. The new pattern is shown below.
After assembly:
