What was found
MCN - MAJOR REPAIR - DURING C-20 CHECK GALVANIC CORROSION WAS FOUND ON UPPER AND LOWER SURFACE OF R-1 DOOR ENTRY WAY CREASE BEAM UPPER CHORD, UPPER LEG, FROM BS 305 TO BS 320, RBL 47, WL 209. MAINTENANCE REMOVED CORRODED UPPER ANGLE OF CREASE BEAM FROM BS 305 TO BS 320, RBL 47; FABRICATED A NEW REPLACEMENT ANGLE; INSTALLED REPAIR PART IAW B737-300 SRM 51-40-02 FIG 12 PG 1 & 45.