By Dan Gallagher, MarketWatch

SAN FRANCISCO (MarketWatch) -- Tech stocks took a hard hit on Friday morning as a disappointing jobs report sparked a broad-market selloff, and warning from F5 Networks sank several other stocks in the telecommunications equipment space.

The Nasdaq Composite Index (RIXF) slid by 1.3% to 3,183 while the Philadelphia Semiconductor Index (SOX) slumped 1.6% and the Morgan Stanley High-Tech Index fell by 2.2%. The Dow was off by more than 150 points after job gains came in at their lowest level in 9 months.

Another major weight on the tech sector came from F5 Networks (FFIV), which slid nearly 19% to $73.80 after the company lowered its earnings and revenue outlook for the second fiscal quarter, citing weaker sales to telecom customers.

At least four brokers downgraded the stock following the warning. The warning also took down other telco equipment stocks; Juniper (JNPR) fell nearly 6%, while JDSU (JDSUD) and Cisco Systems (CSCO) shed more than 2% each in early trades.

Hewlett-Packard (HPQ) fell 1% after announcing that Chairman Ray Lane was stepping down following a weak showing of shareholder support at last month's annual meeting.

Zynga (ZNGA) said venture capitalist John Doerr of Kleiner Perkins has joined its board of directors.

Amazon.com (AMZN) CEO Jeff Bezos made a "significant investment" in the Business Insider website, according to an internal memo released by Business Insider CEO Henry Blodget. Bezos was part of a group that invested $5 million in the site.

One of the morning's few gainers was Facebook (FB), which rose nearly 1% to $27.32. Argus Research upgraded the social network to a buy rating after Facebook unveiled its Home mobile phone software at an event on Thursday.

"We see Facebook Home as a way for the company to strengthen its presence in mobile computing without jumping into the hardware business or even developing its own operating system," analyst Joseph Bonner wrote in a note to clients.

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(END) Dow Jones Newswires

04-05-13 1141ET