Changing ENIAC's vacuum tubes, c. 1940s.
Fullsize image: https://s3-us-west-1.amazonaws.com/h...e_fullsize.jpg
https://s3-us-west-1.amazonaws.com/h...acuum_tube.jpg
Previously:
https://www.homemadetools.net/forum/...669#post174546
https://www.homemadetools.net/forum/...696#post174656
https://www.homemadetools.net/forum/...404#post150836
https://www.homemadetools.net/forum/...999#post168172
https://www.homemadetools.net/forum/...432#post166233
