Linards Ticmanis schrieb:
I should add that I only had a 74HCT11 available as a replacement, which maybe is not close enough in timing to a real 74LS11 to accurately create the LD194 signal.
Generally, HCT (not HC!) is a perfect replacement for the old LS series. Same specification, but 10 times less power consumption.
However -- 74HCT AND today's 74LS (!) are faster than their 1977 counterparts. This may cause trouble with designs that rely on the propagation delay of the gates. In this case you will have to replace more parts to get the same race conditions for each signal involved.
Patrick