What was found
AFTER TAKEOFF, RETRACTED THE GEAR AND TURNED ON YAW DAMPER, GOT THE RUNAWAY TRIM TONE AND AIRPLANE TRIED TO CLIMB 5000 + FT PER MIN, PUSHED THE TRIM INTERRUPT SWITCH, TURNED TOWARD THE RUNAWAY AND DECLARED EMERGENCY, LANDED WITHOUT INCIDENT. DETERMINED THE MOST PROBABLE CAUSE WOULD BE FROM A FAILURE OF RELAYS K21 & K22. REPLACED BOTH RELAYS (PN 974.20.01.212) IAW AMM 24-00-00 AND WD 27-40-00. PERFORMED HORIZONTAL STAB TEST 27-40-00 AND AUTO PILOT CHECK 22-10-00 WITH NO DEFECTS NOTED. PERFORMED FLIGHT OPS CHECK IAW POH. SYSTEMS OPERATED WITHOUT DEFECT AND AIRCRAFT WAS DEEMED AIRWORTHY AND RETURNED TO SERVICE.