The shock news comes a week after Moody's downgraded its credit rating on Sony to junk, saying the maker of Bravia televisions and PlayStation game consoles had more work to do in repairing its battered balance sheet.
Japan's embattled electronics sector, including Sharp and Panasonic, has faced serious challenges from foreign rivals such as US giant Apple and South Korea's Samsung as they were outplayed in the smartphone and low-margin television business.
The deal with Japan Industrial Partners was reportedly worth between 40 billion yen (USD 400 million) and 50 billion yen. No financial details were disclosed.
Citing "drastic changes" in the computer market, Sony said it would concentrate on its lineup of smartphones and tablets and "cease planning, design and development of PC products". The firm is a small player in the global PC business.
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Sony chief Kazuo Hirai said the moves were aimed at "accelerating the revitalisation and growth of our electronics business".
Sony said the TV business would not be profitable in the current fiscal year to March, in which it expects to lose 110 billion yen. The bulk of those losses are tied to restructuring costs.
Sony has pinpointed digital imaging, video games and mobile as the units which it hopes will lead a turnaround in its core electronics business.
Unlike Panasonic, which has abandoned consumer smartphones, Sony has seen buoyant sales of its Xperia offering and record sales for its new PlayStation 4 console.
But Hirai, who has led a sweeping restructuring including asset sales that saw the USD 1.0 billion sale of Sony's Manhattan headquarters, has shrugged off pleas to abandon the ailing television unit. Today, he said Sony would strengthen its focus on the high-end TV business.