BA11-P card cage
It held hex system unit backplanes, and could contain up to roughly seven standard size (4-slot) system units (the documentation formally specifies six), although the backplane used to hold the CPU was a 14-slot (for the -11/60) unit. The backplanes were mounted vertically, facing forward (like those in the later VAX-11/780.
It was one of the BA11 mounting boxes. It was mounted in an H9500 double-width low-boy corporate cabinet produced by DEC; the BA11-P's (up to two per M9500) swung out for full access, not on slides as with the other BA11's.
The BA11-P used one (optionally two) H7420 Power Supplies, which were separate units, permanently mounted directly in the H9500, below and behind the BA11-P; a power harness connected to the two. The power supply contained up to five DEC standard modular regulators; the harness ended in a power distribution panel containing standard DEC power distribution connectors.
- PDP-11/60 cabinet and power supply manual - the BA11-P is covered on pg. 4-7 (pg. 90 of the scanned version) through 4-18