WASHINGTON, Feb 15 - U.S. industrial output slipped again in January, the Federal Reserve said on Friday in a report that still offered some hints of stabilization in the hard-hit manufacturing sector. The Fed said output of the nation's factories, mines and utilities fell 0.1 percent in January, its sixth straight fall following a revised 0.3 percent slip in December. Capacity in use fell to 74.2 percent, the lowest level since April 1983. However, manufacturing output, which makes up the bulk of industrial production, was flat in January -- the first month since July that factory output had not fallen. Overall production excluding motor vehicle assemblies was also flat. The numbers were exactly in line with Wall Street expectations. Analysts polled by had forecast production to fall by 0.1 percent overall and capacity in use to dip to 74.2 percent.