1950s IBM 700 Series Pluggable Logic Module
This 1950s pluggable module is from an IBM 700 Series Mainframe Computer (most likely the 701). Each tube acts as a yes/no logic gate (or bit) and served before ‘memory’ as we know it since the tubes could not actually hold its choice for any length of time. This particular example came from someone who used to work at the IBM museum in the States during the 1970s and kept it when they were throwing it away.
It is in nice original condition and the vacuums tubes still clearly display their IBM logos. The unit has some tarnishing from age and light corrosion to the top. I think this adds to its sense of age.
Great for display.