Leap to heavy industry tried again, modestly

South Korea has found out that money alone can't buy happiness or success - at least not in heavy industry.

Government planners in the mid-1970s saw the country's future prosperity in a rapid shift away from traditional light industries like textiles into the heavy-machinery sector.

Investment was poured into new factories filled with advanced equipment. Several hundred million dollars later, it become apparent that things weren't going as planned.

''The government was right to the extent that the machinery industry is the right one for us,'' Chong Hwan Choi, president of the Hyosung Heavy Industrial Corporation, said. ''But too many people thought that all you had to do was put up a nice building, install modern equipment, and wait for the profits to roll in. They saw only the quantity side and forgot the quality aspects.''

Hyosung, for instance, had three nightmarish years from 1979 to 1981, unable to make a decent profit because of a recession worsened by excessive competition and gross overcapacity. That at least has eased. Two other heavy electrical companies, Kolon and Sangyong, however, found their troubles too much to bear and have folded.

For now, Hyosung's effort is concentrated in Southeast Asia and the Middle East. Eventually, it wants to move into the advanced industrial countries. Mr. Choi sees the company's export weakness as partly a legacy of the overenthusiastic promotion of heavy industry before Korea was ready for it.

''But now morale is picking up and there has been a big increase in productivity. It's an exciting time to be in the business, and I'm glad I made the switch,'' he says.

Much of Hyosung's production is carried on in a relatively outdated suburban Seoul plant. The company, however, is planning to concentrate all its activities at Changwon, on the southern coast, where the government is developing an ambitious park for heavy industry.

Changwon is also just emerging from the woods after several disastrous years that typified what government officials today call the ''delusions of grandeur'' of the former regime.