What was found
EMERGENCY DECLARED - DESCENDING FROM FL400 - 1ST INDICATION WAS WX RADAR FAIL - FOLLOWED BY FLT DK EQ SMOKE AND LT RECIR FAN. THIS WAS FOLLOWED BY EQUIP OVHT. SMOKE LIGHT WAS ON. EADI'S LOST COLOR. MOMENTARILY SMELLED ELECTRICAL BURNING SMELL. T/S IAW FIM 21-58-00. FOUND FLIGHT DECK SMOKE DETECTOR TS5295 FAULTY. R & R DETECTOR TS5295 IAW MM 21-58-19-2. EQUIP COOLING SYS TESTS OK IAW MM 21-58-00-5. OPS TESTED WX RADAR IAW B757-34-43-00-5 PARA 2. OPS CHECK NORMAL. NO OTHER FAULTS OR DEFECTS NOTED.