CORRECTED - UPDATE 3-KLA Tencor posts wider-than-expected loss

(Corrects first name of CEO in 2nd paragraph)

* Q3 adj loss 34 cents/share vs Street view loss 27 cents

* Q3 rev $309.6 mln, down 49 pct

* Sees Q4 adj loss 8-24 cents/share, revenue $270-$310 mln

* Shares up slightly in extended trade (Adds forecast, analyst comment, details, byline)

By Gabriel Madway

SAN FRANCISCO, April 23 (Reuters) - KLA-Tencor Corp (KLAC.O) posted on Thursday a wider-than-expected fiscal third-quarter loss after revenue tanked, as the chip equipment maker struggles with a steep falloff in demand.

However, new orders in the March quarter rose 13 percent from the previous period, but Chief Executive Rick Wallace cautioned that orders had been limited to a small number of customers. He does not expect significant customer investment in expanding capacity until 2010.

The company issued a forecast for the current quarter in the range of Wall Street's estimates, but KLA-Tencor said visibility remained poor and long-term demand difficult to predict.