What was found
ON CLIMBOUT FROM MKE EN ROUTE TO PHX THE NR 3 SLAT WOULD NOT RETRACT. AIRCRAFT RETURNED TO MKE WITHOUT FURTHER INCIDENT. MAINTENANCE TROUBLESHOT IAW BOEING 737-300 MM 27-88-00, REMOVED AND REPLACED M229, FLAP/SLAT POSITION MODULE P/N;65-52807-76 SN; D00880. ALSO REMOVED AND REPLACED L00351, LEADING EDGE FLAP TRANSIT LIGHT. TEAR DOWN REPORT OF THE LEADING EDGE FLAP/SLAT MODULE, SN D00880, CONFIRMS FAULT. THE UNIT FAILED THE ANNUNCIATOR TEST AND UPON TEARDOWN FOUND COLD SOLDER JOINT IN THE A22 BOARD. RE-SOLDERED BOARD AND RE-TESTED IAW BOEING OHM 27-56-40 REV 39.