On Wed, Jul 19, 2017 at 6:10 PM, Eric Smith via cctalk <cctalk@classiccmp.org> wrote: > I'm interested in the history of the logic design for the edge-triggered D > flip-flop, as used in the SN7474... > > Does anyone know what year the SN7474 was introduced, or have an early > datasheet for it (prior to the 1973 TTL Data Book For Design Engineers 1st > Edition?
I have no datasheet, but I have examples on DEC M-series FLIP-CHIP modules from my PDP-8/L, c. 1968. I am pretty sure I have examples with 1968 date codes and possibly 1967 date codes. I do find that when repairing DEC equipment of this vintage, the two most common parts to fail are the 7474s and the 7440s. Others have also written up their repair experiences and these two parts top the list for common failures. -ethan
