Key Tronic (KTCC) sank 12% late Tuesday after the contract electronics manufacturer posted a fourth-quarter sales drop.The Spokane, Wash., company made $7.1 million, or 71 cents a share, for the quarter ended July 1, up from the year-ago $2.8 million, or 28 cents a share. Latest-quarter earnings were boosted by a $5 million tax benefit. Sales fell to $52.5 million from $53.2 million a year earlier. The company said it expects to make 12 to 16 cents a share for the fiscal first quarter on sales of $50 million to $53 million. It also expects a $500,000 charge on due diligence and related expenses incurred in connection with a potential acquisition that the company decided not to complete. Shares sank 79 cents late Tuesday to $6.02.