After two months of darkness, the Times Square "zipper" is back displaying headlines of the day's news. In May, the lights went out on the 369-ft electronic billboard that had operated continuously since 1928. Technicians replaced the 12,400 incandescent light bulbs with 235,000 light-emitting diodes, making it easier to read in bright sunlight. Dow Jones, which has operated the board since June 1995, said the refurbished board was clearer, faster and more reliable.