The PDP-12 Minicomputer

The PDP-12 minicomputer that I have comes in three cabinets; the first cabinet is the PDP-12 minicomputer itself, with 8kW of core memory, two tape drives (TU55), and vector graphics display unit (VR14). See the Module Utilization chart for a listing of the cards.

The next two cabinets are joined together, and form the expansion cabinet. The left cabinet contains an additional 24kW of core memory in the top half, and the FPP-12 floating point unit in the bottom half. The right cabinet contains a TC58 tape controller (most of the top half), and a bunch of other cool modules, listed below.

The nice thing about the main cabinet is that the back of the cabinet swings out for easy servicing of the cards.

The main unit, without the tape drives or CRT or top fans, consumes 580W. The PDP-12 has been partially restored as of fall 2007.

Front View

Even more impressive than the PDP-8/I front panel is the front panel of the PDP-12. Well over 100 lights!

Power Supply

A close-up shot of the PDP-12's power supply. I will need to reform the capacitors before I can apply power to it (having learned from the PDP-8/I restoration). Luckily, the power supply seems to be very similar to the PDP-8/I's power supply. You can read about the restoration of this PDP-12 here.

Dual Tape Drives and Vector Display

This image is a detail of the back of the two tape drives (two top components) and the vector display (bottom component, VR14) in the PDP-12 main cabinet.

Notice the speaker (damaged) at the bottom right of the picture.

Right around the speaker are the various analog and digital I/O points (some controlled by relays) as seen from the front view. The hanging cables are all on my "todo" list.

Expansion Cabinet

The PDP-12 expansion cabinet as viewed from the left. Notice the top half containing the 24kW of core memory, and the bottom half containing the FPP-12 floating-point unit. Unfortunately, the FPP-12 looks like it might have been used as a source for spare modules; it's missing almost all of the modules in the last four rows (there are only 12 cards in the last four rows)!

This is a good view of the TC58 tape controller (top right-hand side).

On the bottom right-hand side, you see where a mouse has built a nest :-( -- luckily, I was able to vacuum out all of the material, but it looks like the mouse had chewed through a few of the 30 gauge wires, so I'll need to figure out how much damage was actually done to the CC02 (whatever that is!) on the bottom. Joy! :-(

The PDP-12 expansion cabinet as viewed from the right. The cabinet is organized as follows:

Back Left Back Right Front Left Front Right 8k of core (M97/MM8IA/5115) 8k of core (M26/MM8IB/0601163) 8k of core (MM8IA/901) FPP-12 (S/N 0700322) DW08A (S/N 707) DW08A (S/N 212) (empty backplane) PT08B (S/N 1630) DM01 (no serial number) DM01 (S/N 583) upside down 8k core (M26/MM8IB/1020) obviously used for spares PT08 (S/N 1634) DW08B (M22/DW08B/173) Power distribution bus (with 10 5-position connectors) (empty space) 854 (empty space) 854 H740D H740D TC58 front panel TC58 PT08 looks like an OMNIBus BA12 (S/N 65) CC02 (S/N N01)