What was found
PDX - DURING PUSHBACK FOR FLIGHT 2471, NR 2 ENGINE WILL NOT START. AIRCRAFT RETURNED TO THE GATE. MAINTENANCE PLACED ON MEL 80-11-3 RSI 346266. MAINTENANCE REPLACED THE STARTER CONTROL VALVE ON 10/24 WITH NO HELP. MEL CONTINUED. ON 10/25 THE K32 RELAY ON THE PCB4 WAS REPLACED WITH NO HELP. REPLACED THE NR 2 ENGINE FADEC WITH NO HELP. REPLACED THE STOP SWITCH ON THE START CONTROL PANEL IN THE COCKPIT. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE. MEL CLEARED.