Train doors not proven closed at front M1 car. TC opened and closed once to clear fault. Fault recur red at PNR1. Staff(PNR) pushed closed front M1 car A1 door b ut to no avail. Staff(PNR) isolated front M1 car A1 door in ~~~~~ RSD found 1612 A1 door control panel faulty, causing train doors to be not proven closed. Replaced door control panel. Performed door cyclic test ok.