Pacific Scientific Co.

Although fourth-quarter net income at Pacific Scientific Co. of Anaheim rose 11% from the year-ago period, profits for the full year sank 54% as demand for what was once the company’s principal product line continued to slump.

The maker of precision industrial and electronic instruments said quarterly net income for the three-month period ended Dec. 31 was $2 million, up from $1.8 million reported for the same period in 1983. Revenues during the quarter rose 27.7% to $24 million from the $18.8 million in the previous year.

For the year, Pacific Scientific reported net income of $7 million, down from the $10.8 million earned during 1983. Annual revenues for 1984, however, grew to a record $92.2 million from $81.4 million in 1983, a 13% increase. Revenue amounts for both 1983 and 1984 exclude the Industrial Sales Division that was sold last October to a group of its managers for an undisclosed price.

Pacific Scientific attributed the decline in 1984 profits to a continued drop in the sales of highly profitable mechanical shock arrestors, which protect pipes in nuclear power plants from earthquake damage. Sales of arrestors--which dropped to $10.1 million in 1984 from $32.6 million the year before--were hard hit by a slowdown in the construction of nuclear power plants, the company said.

Despite the declining sales of arrestors, the company managed to boost overall revenue during 1984 by acquiring Honeywell Inc.’s Motor Products unit last February. The new motor and control division brought in $26.9 million in additional revenue in 1984. Profit margins on the division’s lines of specialty motors is lower than the margin on arrestors, the company said.

Richard V. Plat, senior vice president of finance and administration, said Pacific Scientific expects the demand for the arrestors to “hold flat or decline� during 1985.

To offset the drop, the company is seeking to diversify through further acquisitions, Plat said. The company’s activities revolve around three main activities: electronic instruments, motors and controllers and aerospace products.

As the company experienced changes in its product during 1984, it also experienced changes in management. In late August, the company announced the resignation of Stephen J. Toth as president and chief executive officer.

Toth was replaced by Harry R. Goff, who said in a statement that the company’s three main product lines have “niches with good growth prospects in which we have established positions of leadership.�