ByJohn S. McClenahen More repair work needs to be done on corporate balance sheets -- paying down debt and improving cash balances -- before companies will focus on increasing their capital spending. And that means, says David Rosenberg, Merrill Lynch & Co.'s chief North American economist, the U.S. economic recovery "might not begin to feel like one until well into 2004, perhaps even 2005." How have major economic sectors fared so far on balance-sheet repairs? Analyzing the S&P 500 companies, Rosenberg gives good marks to utilities and healthcare and his worst mark to industrials. Just slightly better than industrials, but still with weak balance sheets, are the energy, technology and materials sectors of the U.S. economy, he says.