One answer to this question suggests the following circuit to drive a LED from an open collector output of a 74LS47:
What is the purpose of the R1 resistor? What would happen if R1 would be missing?
I did a simulation, but could not find a different behavior regardless whether or not R1 was present.
(I could have added this question in the original question as a comment to the answer, but I did not want to make the already excessively long list of comments even longer. Therefore I created a separate question. I hope that is OK.)