Michael Gardi's Precision CRT Type 30 Replica Goes Great with a PiDP-1

Vintage computing enthusiast Michael Gardi has built an accessory for a Digital PDP-1 replica, to add a little verisimilitude to its usage: a 2:3-scale DEC Precision CRT Type 30 display unit.

"When Oscar Vermeulen released his PiDP-8/I reproduction I knew that I had to have one," Gardi explains of the project's origins. "When I got mine assembled I thought it would be cool to connect to it through a period-ish terminal so I created a 2:3 Scale VT100 reproduction. Now Obsolescence Guaranteed has released their new PiDP-1 Replica. I thought I would make a 2:3 scale DEC Precision CRT Display Type 30 reproduction to go with it."

The Digital Equipment Corporation (DEC) Programmed Data Processor-1 (PDP-1) minicomputer launched in 1959 with 4,096 words of magnetic-core memory, a 187kHz CPU, and punched paper tape storage at a hefty $120,000 — equivalent to $1.34 million today. For that, at least, it came bundled with something of a luxury for systems of the era: a cathode-ray tube (CRT) display, allowing for more interactivity than a teletype terminal and leading directly to the development of Steve Russell's 1962 simulation game Spacewar!.

The PDP-1 launched DEC's rise in the microcomputer market, but at 1,600lbs the chunky machine isn't exactly desk-friendly — unlike Vermeulen's PiDP-1, a scale replica running an emulator on Raspberry Pi hardware. While Vermeulen has replicated the PDP-1 itself, though, it relies on the user's own display — which is where Gardi's scale replica of the DEC Type 30 comes in.

"The 19 inch CRT inside the Type 30 was used primarily for radar screens. Not many of those kicking around any more," Gardi notes, "or for that matter CRTs of any size." As a result, the scale replica uses a more modern LCD — square-format, hidden with a bezel replicating the circular display of the real Type 30. "Pretty happy with the overall look. I like the colors. I think it's a pretty close approximation to the front three inches of a real Type 30 (at 2:3 scale)."

More information on the project is available on Gardi's Hackaday.io page.