While I'm sure that you've probably satisfied your curiosity by now or written it off as a vagary of the market, here's some more information:

http://www.ttmtech.com/news/press_releases/current/pr_080411...

This is TTM's press release covering what happened. The specific relative information is also posted below.

Due to a non-cash asset impairment charge of $48.1 million, we recorded an operating loss for the second quarter of $8.5 million compared to operating income of $45.7 million in the first quarter. Excluding the asset impairment charge, operating income for the second quarter was $39.6 million.

And:

The second quarter impairment charge primarily related to equipment at a plant that was acquired in 2007. While we previously had reduced the carrying value of some of these assets during purchase accounting, weaker than expected performance at this facility led us to record an additional impairment in the second quarter. This equipment is not suited for the advanced technology demands of our current customers.

This, along with a revised (lower) guidance, caused the stock price to tumble. Also keep in mind that if a stock does something very strange (like lose 26% of its share price in a few days) the best place to look for answers will generally be the Press Release or Financial Reports section of that company's website.