Santa Clara-based Zycon Corp. said it has terminated its deal to be acquired by Dallas-based buyout firm Hicks Muse Tate & Furst after agreeing to be purchased by rival printed circuit board maker Hadco Corp. for about $205 million in cash. . . . Marina del Rey-based Thompson PBE Inc. said it will buy back up to 500,000 shares of its common stock. . . . American Express Co. bought a 51% stake in San Diego-based student loan broker Educational Funding Co. for undisclosed terms. . . . Los Angeles-based Times Mirror Co. agreed to sell its CRC Press Inc. unit to Information Ventures, a company owned by Warburg, Pincus Ventures and investor Mason Slaine, for undisclosed terms.