Ken Shirriff's blog

Computer history, restoring vintage computers, IC reverse engineering, and whatever

Showing posts with label ibm1401. Show all posts

Showing posts with label ibm1401. Show all posts

An 8-tube module from a 1954 IBM mainframe examined: it's a key debouncer

IBM's vacuum tube computers of the 1950s were built from pluggable modules, each holding eight tubes and the associated components. I re...

Repairing a 1960s mainframe: Fixing the IBM 1401's core memory and power supply

A few weeks ago, I wanted to use one of the vintage IBM 1401 mainframe computers at the Computer History Museum, but the computer wasn't...

Repairing a 1960s-era IBM keypunch: controlled by mechanical tabs and bars

In this article I describe repairing an IBM 029 keypunch that wouldn't punch numbers. Keypunches were a vital component of punch card co...

Creating a Christmas card on a vintage IBM 1401 mainframe

I recently came across a challenge to print a holiday greeting card on a vintage computer, so I decided to make a card on a 1960s IBM 140...

Identifying the "Early IBM Computer" in a Twitter photo: a 405 Accounting Machine

The photo below of a "woman wiring an early IBM computer" has appeared on Twitter a bunch of times , and it stoked my curiosity:...

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