Summary Box: hip shortage set off by recession makes smart phones more scarce

THE SHORTAGES: Customers must wait for some smart phones including HTC Corp.'s EVO 4G and Motorola Inc.'s Droid X. Manufacturers expect delays through the year.

MISSING PARTS: It's generally a problem with a component here and there, but if just one of the 20 to 30 critical chips that go into a smart phone is unavailable, the whole production line falters.

THE REASON: Manufacturers that produce these chips scaled back investment and capacity during the recession. Now, they can't scale up production fast enough.