SENATE WANTS JAPAN SEMICONDUCTER PACT ENFORCED The U.S. Senate has unanimously called for President Reagan immediately to force Japan to live up to a pledge to stop dumping its microchips and open its markets to U.S. Chipmakers. The Senate voted 93 to 0 to urge Reagan to impose penalties on Japanese high-technology products containing semiconductors in retaliation for what it sees as Japan's violations of the semiconductor pact. While the measure does not bind Reagan to any action, Senate leaders said its adoption would warn Japan stiffer legislation would be considered if the violations continue. "We want to send a message to Japan to let it know how the Senate feels about this matter," Senate Democratic Leader Robert Byrd told the Senate. Senate Finance Committee chairman Lloyd Bentsen told the Senate the measure was not aimed at retaliation but at correcting Japan's unfair trade practices. A key House trade lawmaker, Representative Richard Gephardt also announced he would seek to force Japan and other countries with huge trade surpluses to slash their surplus by 10 pct a year for three years.