return to main pagePhoto by Ken Shirriff, uncovering the unit by Anonymous
Hidden away, in a deep dark place in the 1402 card reader/punch, is a vacuum tube test amplifier (overdriven to be a switch) used to drive the neon tubes on the 2 test alignment rotating disks. One rotating disk for the card reader event timing, and one rotating disk for the card punch event timing.
Vacuum tubes in a 1402?? - indeed :-))
Evidently the directive, sometimes called "Solid State in '58", did not apply to test/alignment equipment. There is a suspicion that the vacuum tube test amplifier was well hidden to reduce customer/competitor comments and questions ;-))
For further details and usage, see - well, we gotta work that out ;-))