No ball was dropped in Times Square from 1942 through 1943 because of wartime blackouts.
The Times Square Ball tradition was suspended for two New Year's Eves during World War II. New York City followed blackout rules designed to reduce the chance that illuminated coastal cities could help enemy aircraft or ships navigate. As a result, the lights and public spectacle associated with the ball drop could not proceed normally.
People still gathered in Times Square during those years, but the midnight moment was marked by silence and bells rather than a descending illuminated ball. The ball-drop tradition resumed after the war, beginning again for the transition into 1944.
This interruption is sometimes misremembered as a change to the ball's design or as a smaller drop. The key fact is that there was no ball drop at all in 1942 and 1943. The annual event later returned and became one of New York City's most recognizable celebrations.