What was found
ON TAXI OUT ELP, INBOARD FLAPS WOULD NOT EXTEND TO THE SELECTED POSITION OF 15 DEGREES. MX ADVISED TO RESET INBOARD T/E FLAP POSITION CB. RESET INDICATOR WENT FROM 0 DEGREES TO 20 DEGREES. TAXI BACK TO GATE. WENT TO APU AND FLAPS THEN INDICATED 15 DEGREES. T/S FLAP POSITION INDICATION SYSTEM FOR I/B TRAILING AFT FLAPS. FOUND TERMINALS ON FLAP C/B REPLACED I/B FLAP C/B FOUND PIN B2 RECESSED ON R 187 RELAY REPOSITIONED PIN B2. REPLACED R187 RELAY SWAPPED BUS PROTECT ION PANEL, NO HELP. REINSTALLED ORIGINAL BUS PROT PANEL. REMOVED AND REPLACED I/B FLAP BY-PASS VALVE IAW B727 MM 27-51-151. REMOVED CONNECTOR SHELLS ON I/B FLAP INDICATOR, LEFT AND RIGHT FLAP POSITION XMITTER, I/B FLAP BYPASS VALVE.