Toshiba Corp. posted a wider-than-forecast operating loss after the troubled electronics conglomerate wrote down the value of its Westinghouse power unit. The preliminary operating loss was 690 billion yen ($6.2 billion ) in the 12 months ended March, compared with a forecast loss of 430 billion yen, the Tokyo-based company said Tuesday. Analysts were projecting, on average, a loss of 417 billion yen, according to estimates compiled by Bloomberg. Toshiba, which makes everything from computers to nuclear power equipment, is trying to recover from an accounting scandal that has forced the sale of assets and executive resignations. Total sales were 5.5 trillion yen for the fiscal year, below the company’s earlier forecast for 6.2 trillion yen.