IBM Type 31 Alphabetical Duplicating Keypunch available, Seattle area

Josh Dersch derschjo at
Tue Feb 11 18:14:47 CST 2020

On Tue, Feb 11, 2020 at 9:44 AM Al Kossow via cctalk <cctalk at>

> On 2/11/20 8:28 AM, Rick Bensene via cctalk wrote:
> > It has a label on it that says "BR 2412".
> Bunker-Ramo, originally Nuclear Data NDP-812

Yep.  12-bit machine, four accumulators, multiply/divide logic standard.
All built on a single large, wire-wrapped board stuffed with 9000-series
logic, using extremely poor quality wire-wrapped sockets.  The one in that
picture almost works properly after a week or three of cleaning and
debugging (the mul/div hardware screws up somewhere and I never tracked it
down).  Bigger issue is that my unit doesn't have any I/O devices at all,
so I'll have to build one.

The BR 2412 is basically identical to the ND-812, except the latter used
core memory and the former uses battery-backed SRAM.  (Big lead-acid
battery in there.)

> Hang in there, man.

- Josh

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