* Toshiba Q3 op profit Y29.3 bln vs Y8.67 bln year ago
* Keeps its full-year operating profit forecast of 260 bln yen
TOKYO Jan 31 (Reuters) - Japan's Toshiba Corp posted a rise in quarterly operating profit on Thursday, but missed forecasts as a weak global economy and a drop in sales of televisions and personal computers offset buoyant orders for new thermal power stations.
Toshiba, which makes NAND flash memory chips used in Apple Inc's iPhones, posted an operating profit of 29.3 billion yen ($322 million) in the October-December quarter, up from 8.67 billion yen last year, boosted by large infrastructure orders.
The result came in below an average forecast for a 47.6 billion yen profit estimated by four analysts polled by Thomson Reuters I/B/E/S.
However Toshiba, which cited the weak global economy as a drag on earnings, stuck to its full-year forecast for operating profit of 260 billion yen for the year ending March 31, helped by recovering prices for NAND memory chips.
Strong orders in its power division and infrastructure orders offshore boosted profits.
But the digital products division, home to the company's LCD TVs, fell to a 15.6 billion yen operating loss after logging a 10.6 billion yen loss in the same division last year. PC sales also declined due to eroding demand in the United States.
Toshiba is the world's No. 2 maker of NAND flash memory chips after Samsung Electronics Co Ltd.
The $18.4 billion company, whose sprawling business ranges from nuclear power to washing machines, is one of Japan's largest and the yen's recent weakness is likely to boost profits at the major exporter. More than half of Toshiba's revenue is made overseas.
The yen has weakened nearly 8.6 percent against the dollar since Prime Minister Shinzo Abe's party was voted into office on Dec. 16, promising to press for aggressive monetary easing from the central bank and saying it was committed to fight deflation.
Rivals Hitachi Ltd and Mitsubishi Electric Corp both report quarterly results early next week.
Shares in Toshiba ended down 1.3 percent at 406 yen ahead of the results. Toshiba's shares have gained 20 percent so far this year, outperforming a 7.2 percent rise on Tokyo's benchmark Nikkei.
A Reuters analysis shows that Toshiba is trading at a twelve month forward P/E of 11.6, whereas the benchmark Nikkei Index is trading at 12 month average forward P/E of 16.5.