DSCN0434

16 Nixie Tubes. Burroughs B-7971. Driven by custom built driver cards.
Using 74LS TTL, and 74HC, and 4000 CMOS logic.
Uses 12-bit Primary and Scanning counters, driven by 4017 decade counter
based tube-selector counters running at 8 kHz and scanning successive groups of (16) memory addresses. Memory is a Dallas Semiconductor
DS-1220 nonvolatile 2K x 8 bit SRAM. Character generator is (2) 27C256
Eproms with addresses is parallel to form a 16-bit wide output.
Eprom addresses are ASCII chartacters, and Eprom outputs are used to activate the proper tube segments for each character. Both of those Eproms were coded by hand using dip switches back in year 2000.